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  • 201.
    Högström, Gabriel
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    High aerobic fitness in late adolescence is associated with a reduced risk of myocardial infarction later in life: a nationwide cohort study in men2014In: European Heart Journal, ISSN 0195-668X, E-ISSN 1522-9645, Vol. 35, no 44, p. 3133-3140Article in journal (Refereed)
    Abstract [en]

    AIMS: Cardiovascular disease is the leading cause of morbidity and mortality worldwide, and signs of atherosclerosis are present in all large arteries already in adolescence. We investigated the association between high physical fitness in late adolescence and myocardial infarction (MI) later in life.

    METHODS AND RESULTS: The study cohort comprised 743 498 Swedish men examined at the age of 18 years during conscription 1969-84. Aerobic fitness (Wmax) and muscle strength at conscription were measured using standardized methods. Myocardial infarctions occurring in the cohort were tracked through national registers. During a median follow-up period of 34 years, 11 526 MIs were registered in the cohort. After adjusting for age, body mass index (BMI), diseases, education, blood pressure, and socio-economic factors, one standard deviation increase in the level of physical fitness (Wmax) was associated with an 18% decreased risk of later MI [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.80-0.85]. The beneficial effects of Wmax were significant across all recognized BMI groups, ranging from lean (BMI < 18.5) to obese (BMI > 30) (P < 0.05 for all). However, obese men (BMI > 30) in the highest fourth of Wmax had a higher risk of MI than did lean men (BMI < 18.5) in the highest (HR 4.6, 95% CI 1.9-11.2), and lowest (HR 1.7, 95% CI 1.2-2.6) fourth of Wmax.

    CONCLUSIONS: We report a significant graded association between aerobic fitness in late adolescence and MI later in life in men. However, obese men with a high aerobic fitness had a higher risk of MI than lean men with a low aerobic fitness.

  • 202.
    Högström, Gabriel
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Body composition and performance: influence of sport and gender among adolescents2012In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 26, no 7, p. 1799-1804Article in journal (Refereed)
    Abstract [en]

    Body composition is well known to be associated with endurance performance amongst adult skiers, however the association among adolescent cross-country and alpine skiers is inadequately explored. The study sample was comprised of 145 male and female adolescent subjects (aged 15-17 years), including 48 cross-country skiers, 33 alpine skiers, and 68 control subjects. Body composition [%body fat, %lean mass, bone mineral density (g/cm2)] was measured with a dual-emission X-ray absorptiometer, and pulse and oxygen uptake were measured at three break points during incremental performance tests to determine physical fitness levels. Female cross-country and alpine skiers were found to have significantly higher %lean mass (mean difference = 7.7%, p < 0.001) and lower %body fat (mean difference = (8.1%, p < 0.001) than female control subjects. Male cross-country skiers were found to have lower %body fat (mean difference = 3.2%, p < 0.05) and higher %lean mass (mean difference = 3.3%, p < 0.01) than male alpine skiers and higher % lean mass (mean difference = 3.7%, p < 0.05) and % body fat (mean difference = 3.2%, p < 0.05) than controls. The present study found strong associations between %lean mass and the OBLA and VO2 max weight adjusted thresholds among both genders of the cross-country skiing cohort (r = 0.47-0.67, p < 0.05) and the female alpine skiing cohort (r = 0.77-0.79, p < 0.001 for all). The present study suggests that body composition is associated with physical performance already in adolescent athletes.

  • 203.
    Högström, M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, H
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, R
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thorsen, K
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, P
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Current physical activity is related to bone mineral density in males but not in females.2007In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 28, no 5, p. 431-436Article in journal (Refereed)
  • 204.
    Högström, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Relationship between vitamin D metabolites and bone mineral density in young males: a cross-sectional and longitudinal study.2006In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 79, no 2, p. 95-101Article in journal (Refereed)
  • 205.
    Högström, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Retinol, retinol-binding protein 4, abdominal fat mass, peak bone mineral density, and markers of bone metabolism in men: the Northern Osteoporosis and Obesity (NO2) Study.2008In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 158, no 5, p. 765-770Article in journal (Refereed)
    Abstract [en]

    CONTEXT: The association between retinol and bone mineral density (BMD) in males after puberty has not been fully investigated previously. OBJECTIVE: To investigate the association between retinol, retinol-binding protein-4 (RBP-4), BMD (g/cm(2)), abdominal fat mass, and markers of bone metabolism in young men. DESIGN: Longitudinal study. PARTICIPANTS: Seventy-eight healthy males with a mean age of 22.6+/-0.7 years at baseline. A follow-up was conducted in 73 of the participants 2.0+/-0.4 years later. MAIN OUTCOME MEASURES: Associations between serum concentrations of retinol and RBP-4, and BMD of the total body, lumbar spine, and hip, serum concentrations of osteocalcin, and carboxy terminal telopeptide of type 1 collagen (CTX), were investigated. RESULTS: Both retinol and RBP-4 showed an inverse relationship with that of osteocalcin (r=-0.23 to -0.25, P<0.05). Levels of RBP-4 (r=0.26, P=0.02) and osteocalcin (r=-0.23, P=0.04) were also related to abdominal fat mass, and the relationship between RBP-4, retinol, and osteocalcin disappeared after adjusting for this influence of abdominal fat mass. Neither retinol nor RBP-4 concentrations were associated with BMD at any site, CTX as baseline, or changes in BMD during the 2-year follow-up period. Levels of RBP-4 showed a strong association with levels of retinol (r=0.61, P<0.001). CONCLUSION: We found a negative association between the bone formation marker osteocalcin with retinol and RBP-4. The association disappeared when adjusting for the influence of abdominal fat mass. Neither retinol nor RBP-4 were associated with peak BMD in young men.

  • 206.
    Högström, Magnus
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    n-3 Fatty acids are positively associated with peak bone mineral density and bone accrual in healthy men: the NO2 Study2007In: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, ISSN 0002-9165, Vol. 85, no 3, p. 803-807Article in journal (Refereed)
    Abstract [en]

    Background:Knowledge of the influence of nutritional intake on bone health is limited. Polyunsaturated fatty acids have been suggested to influence bone growth and modeling in humans, although data are sparse.

    Objective:The objective was to investigate the role of fatty acids in bone accumulation and the attainment of peak bone mass in young men.

    Design:The cohort studied consisted of 78 healthy young men with a mean age of 16.7 y at baseline. Bone mineral density (BMD; in g/cm2) of total body, hip, and spine was measured at baseline and at 22 and 24 y of age. Fatty acid concentrations were measured in the phospholipid fraction in serum at 22 y of age.

    Results:Concentrations of n−3 fatty acids were positively associated with total BMD (r = 0.27, P = 0.02) and spine BMD (r = 0.25, P = 0.02) at 22 y of age. A positive correlation between n−3 fatty acid concentrations and the changes in BMD at the spine (r = 0.26, P = 0.02) was found between 16 and 22 y of age. Concentrations of docosahexaenoic acid (DHA, 22:6n−3) were positively associated with total BMD (r = 0.32, P = 0.004) and BMD at the spine (r = 0.30, P = 0.008) at 22 y of age. A positive correlation was also found between DHA concentrations and the changes in BMD at the spine (r = 0.26, P = 0.02) between 16 and 22 y of age.

    Conclusion:The results showed that n−3 fatty acids, especially DHA, are positively associated with bone mineral accrual and, thus, with peak BMD in young men.

  • 207.
    Janaudis-Ferreira, Tania
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Henriksson-Larsn, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lundgren, Rune
    Wadell, Karin
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Differences in training effects following training with and without supplemental oxygen in patients with COPD2009In: Advances in Physiotherapy, ISSN 1403-8196, E-ISSN 1651-1948, Vol. 11, p. 186-192Article in journal (Refereed)
  • 208.
    Janaudis-Ferreira, Tania
    et al.
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Physiotherapy.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lundgren, Rune
    Wadell, Karin
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Physiotherapy.
    Mechanisms of improved physcical performance after training with and without oxygen in patients with chronic obstructive pulmonare disease2007Conference paper (Other academic)
  • 209. Jianwei, Ju
    et al.
    Shizhang, Zhou
    Tiquan, Zhu
    Ji-Guo, Yu
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Yali, Shi
    Jingmin, Wang
    Effects of Chinese medicine supplementation on exercise capacity in mice1998In: Chinese journal of sports medicine, ISSN 1000-6710, Vol. 17, no 02, p. 158-161Article in journal (Refereed)
    Abstract [zh]

    动物试验表明中药“强身液”可提高机体抗氧化能力及抗氧化酶活性,降低脂质过氧化水平,具有外源性自由基防御物质的作用和提高机体各种能力的功效。人体试验表明该制剂具有提高运动能力,消除运动后疲劳与紧张情绪的作用。

  • 210.
    Johansson, Cecilia
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Jonsson, Mari
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Marttila, Marko
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Persson, David
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Fan, Xiao-Long
    Skog, Johan
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Frängsmyr, Lars
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Wadell, Göran
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Arnberg, Niklas
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Adenoviruses use lactoferrin as a bridge for CAR-independent binding to and infection of epithelial cells2007In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 81, no 2, p. 954-963Article in journal (Refereed)
    Abstract [en]

    Most adenoviruses bind to the coxsackie- and adenovirus receptor (CAR). Surprisingly, CAR is not expressed apically on polarized cells and is thus not easily available to viruses. Consequently, alternative mechanisms for entry of coxsackievirus and adenovirus into cells have been suggested. We have found that tear fluid promotes adenovirus infection, and we have identified human lactoferrin (HLf) as the tear fluid component responsible for this effect. HLf alone was found to promote binding of adenovirus to epithelial cells in a dose-dependent manner and also infection of epithelial cells by adenovirus. HLf was also found to promote gene delivery from an adenovirus-based vector. The mechanism takes place at the binding stage and functions independently of CAR. Thus, we have identified a novel binding mechanism whereby adenovirus hijacks HLf, a component of the innate immune system, and uses it as a bridge for attachment to host cells.

  • 211.
    Johansson, Jonas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    The complexity of exercising in the fasted state2010Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The current study investigated the effects of 60 minutes of moderate exercise performed by endurance-trained men in the fed and the fasted state. The aim was to compare and evaluate the effects of the two trials, both during the 1-hour cycle ergometer test and also during the following 5,5-hour rest period. Seven healthy and well-trained men volunteered to participate in the study. Pre-testing with a maximal cycle-ergometer test was done to determine the workload prior to the main trials. Subjects arrived at the main experiments in the fasted state, and whether they were doing their fasted or fed state trial, they either received a small carbohydrate-rich meal or remained in the fasted state. They performed a cycle-ergometer test for 60 minutes with workloads ranging from 55-70% of their maximal performance during pre-testing and afterwards they received identical meals and remained in a resting position throughout the rest of the day. The current study measured FFA, RER, insulin, glucose, lactate, oxygen uptake (VO2), body temperature and heart rate. The concentrations of FFA were significantly higher during the exercise in the fasted state, mainly during the actual cycle ergometer test and 90 minutes post-exercise. There was no significant difference in the use of substrate (RER) between the two trials and the insulin concentration was significantly higher post-exercise during the fed trial. The glucose concentration was significantly higher during the fasted trial, mainly during the cycle ergometer test. There were no significant differences on body temperature, lactate, VO2 or heart rate. It is concluded that, even while having a significant FFA release during and immediately post-exercise, well-trained males does not gain any significant advantage in fat oxidation when performing moderate interval-based (55% to 70% VO2max) exercise in the fasted state.

  • 212.
    Jonasson, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    A comparison between MOXUS modular metabolic system and AMIS 20012014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Introduction: There are various different methods to measure VO2 max in people. The Douglas Bag method is still seen as a criterion method, however, in recent years there has been a rise in the use of automatic gas analyzers that provide information in real time. It is only a few studies that have looked at gas analyzers during high intensity.

    Purpose: The purpose of the present study was to compare the MOXUS modular metabolic system with the AMIS 2001. Nine participants, age 29 ± 10 years, completed three VO2 max tests via The Bruce Treadmill Protocol. Two tests were measured via the MOXUS system and one via the AMIS. These were conducted in a random order. The VO2, VC02, VE and RQ were compared between tests.

    Results: At low intensities there was no significant difference between gas analyzers, however at maximum intensity the AMIS recorded higher VO2 (p<0, 01), VCO2 (p<0,001), VE (p<0, 05) and RQ (p<0,001). Between the two tests measured with the MOXUS system, there were no significant differences at maximum intensity.

    Discussion: The higher values measured via the AMIS system can perhaps be explained by differences in sensitivity to high ventilations. If there is a difference in ventilation there will obviously be a difference in VO2 and VCO2. The fact that RQ was also significantly higher at maximum intensity shows that the AMIS measures a greater difference between VO2 and VCO2 than the MOXUS system. The CV value for MOXUS between the two tests was very high in comparison to other studies, this can be because there was a relatively large difference in how well trained the participants were.

  • 213.
    Jonasson, Mats
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Sjöberg, Felicia
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Att behandla ARTROS: En jämförelse mellan olika behandlingssteg för artros i knäleden2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Osteoarthritis is a chronic progressive disease which can be accomplished by primary and secondary factors. Pain, stiffness and loss of mobility in the joint are the most common symptoms. Osteoarthritis is explained as an imbalance between the demands on the joint and its ability to fulfill them. This mostly affects the knee joint and individuals of all ages. Individuals who practice sports, especially contact sports, are at higher risk of developing osteoarthritis at a young age. Today, nothing that can stop the progression of osteoarthritis, and it is therefore important to treat the disease in order to relieve pain, improve knee function and increase the life quality.

     

    To relieve the pain that may occur in osteoarthritis is for instance paracetamol, orthopedic devices and NSAIDs successful treatments. In case of very severe pain, cortisone can be used. Even weight reduction, glucosamine intake and regular exercise have positive effects. The latter not only reduces pain, but also improves life quality, knee function and may slow the disease process. In the treatment of secondary osteoarthritis, exercise in combination with glucosamine intake is the most used methods.

    There are three steps in the treatment of osteoarthritis, these are: a) basic treatment, b) adjunctive treatment, and c) surgical treatment. The basic treatment is used for mild osteoarthritis and consists of training, education and weight reduction. Adjunctive treatment is used when the basic treatment is not adequate and includes such as orthopedic devices and medicines. The last option for severe osteoarthritis is surgical procedures, which are arthroscopy, osteotomy, local treatment and arthroplasty.

    The primary treatments for osteoarthritis of the knee joint are exercise, followed by glucosamine intake, arthroplasty and weight reduction. For mild to moderate osteoarthritis is exercise the best treatment, both in terms of efficiency and cost.

  • 214.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Eccentric training in the treatment of tendinopathy2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chronic painful tendinopathies are common, not only in sports and recreationally active people, but also among people with a sedentary lifestyle. Both the lower and upper limbs are affected. There is lack of knowledge about the etiology and pathogenesis to tendinopathy, and many different treatments options have been presented. Unfortunately, most treatments have not been tested in scientific studies. Conservative (non-surgical) treatment has since long shown unsatisfactory results and surgical treatment is known to give unpredictable results.

    The aim of this thesis was to evaluate new models of painful eccentric training for the conservative treatment of different chronic tendinopathies. After promising results in a pilot study, using painful eccentric calf muscle training in patients with chronic mid-portion Achilles tendinopathy, we investigated if these results could be reproduced in a larger group of patients with both mid-portion and insertional Achilles tendinopathy (study I). After 12 weeks, 89% of the patients with pain from the mid-portion were satisfied and back in previous activities. In the group with insertional Achilles tendinopathy the results were poor. A new model for eccentric training was designed for patients with insertional Achilles tendinopathy. The eccentric calf muscle training was done from tip-toe to floor level (study II). With this new regimen 67% of the patients were satisfied and back in previous activities. The next step was to investigate the effects of painful eccentric quadriceps training on patients with jumper´s knee/patellar tendinopathy (study III). Two different training protocols were used. Eccentric training performed on a 250 decline board showed promising results with reduced pain and a return to previous activities, while eccentric training without the decline board had poor results. In a following prospective study, patients with jumper´s knee/patellar tendinopathy were randomised to either concentric or eccentric painful quadriceps training on a 250 decline board (study IV). After 12 weeks of training, there were significantly better results in the group that did eccentric training. In a pilot study (study V), we investigated painful eccentric deltoideus and supraspinatus muscle training on a small group of patients on the waiting list for surgical treatment of subacromial impingement syndrome. After 12 weeks of training, 5 out of 9 patients were satisfied with the results of treatment and withdrew from the waiting list for surgery.

    In conclusion, the present studies showed good clinical results with low risks of side effects and low costs. Thus, we suggest that painful eccentric training should be tried in patients with Achilles and patellar tendinopathy before intratendinous injections and surgery are considered. For patients with chronic painful impingement syndrome, the results of our small pilot study are interesting, and stimulates to randomised studies on larger materials.

  • 215.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Superior results with eccentric compared to concentric quadriceps training in patients with jumper's knee: a prospective randomised study2005In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 39, no 11, p. 847-850Article in journal (Refereed)
  • 216.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Sunding, Kerstin
    Fahlström, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Cook, Jill
    New regimen for eccentric calf muscle training in patients with chronic insertional Achilles tendinopathy: results of a pilot-study2008In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 42, no 9, p. 746-749Article in journal (Refereed)
  • 217.
    Jonsson, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Wahlström, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Ohberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Eccentric training in chronic painful impingement syndrome of the shoulder: results of a pilot study2006In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 14, no 1, p. 76-81Article in journal (Refereed)
  • 218. Kalawy, Hatem
    et al.
    Stålnacke, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Fahlström, Martin
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Professionell Development. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Öhberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Linetsky, Felix
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    New objective findings after whiplash injuries: High blood flow in painful cervical soft tissue: An ultrasound pilot study2013In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 4, no 4, p. 173-179Article in journal (Refereed)
    Abstract [en]

    Background

    The presence of high blood flow in the structurally abnormal and painful regions of tendinosis, but not in the normal pain-free tendons, was recently confirmed by colour Doppler (CD) ultrasound (US). Biopsies from the regions with high blood flow demonstrated the presence of sympathetic and sensitive nerve fibres juxtapositioned to neovessels. Grey-scale US and CD are reliable methods used to evaluate structural homogeneity, thickness, and blood flow in the peripheral tendons. The aim of this study was to utilize CD to qualitatively evaluate for the presence of abnormal high blood flow in paravertebral tissues after whiplash injuries in patients with chronic neck pain.

    Methods

    Twenty patients with chronic neck pain after whiplash-associated disorder (WAD) and 20 pain-free control subjects were included in the study. The same experienced radiologist performed all grey-scale US and CD examinations.

    Results

    More regions with high blood flow were observed in the patient group than in the control group. At all levels, the high blood flow pattern was detected at the enthesis of the spinous processes and bilaterally juxtapositioned to the facet joints.

    Conclusion

    All regions identified by the patients as painful and tender corresponded to the positive high blood flow found during the CD examination.

    Implications

    These findings document increased blood-flow/neovascularisation at insertions of neck muscles which may indicate that there are pathological neovascularisation with accomanying pain- and sympathetic nerves, similar to what has been found in Achilles-tendinosis. These findings promise that similar treatments that now is successful with Achilles tendinosis, may be effective in the WAD-painful muscle insertions of the neck.

  • 219.
    Kalezic, Ivana
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Experimental studies of spinal mechanisms associated with muscle fatigue2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Muscle fatigue is ubiquitous in every day life.Muscle fatigue might be considered as an altered state of motor behaviour, which impairs motor performance. By contrast, muscle fatigue could also be considered a positive phenomenon, which protects muscle tissue from damage that might be incurred to it by overuse.

    The principal aim of the thesis was to explore some of the mechanisms of muscle fatigue at the spinal level in animal models.The activation of multiple motor units of a single calf muscle may influence contractile properties of its neighbouring, otherwise inactive units, providing evidence for spatial spreading of fatigue between different muscle parts. The release of metabolites, their action on inactive muscle units and the effects of local hypoxia are the most likely causes. Fatigue-induced metabolite shift in the interstitium provokes excitation and/or sensitisation of high-threshold afferent fibers, with complex effects on the spinal premotoneuronal network involved in the modulation of motoneuronal output. This was examined by studing the intrasegmental lamellar distribution of the lumbar spinal interneurons following fatiguing contractions of the triceps surae muscle. Furthermore, fatigue of calf muscles enhanced the activity of fusimotor neurons to these muscles irrespective of the regime of muscle activity (isometric vs. lengthening) in conditions that simulate locomotion. Altered fusimotor activity, through increased or maintained muscle spindle afferent responsiveness may be advantageous, providing support to the skeletomotor activity and enhanced information about muscle periphery to higher nervous centres. The particular effects of interneuronal network at motor input (presynaptic inhibition system) and output (recurrent inhibition system) stages were then addressed. Fatigue of triceps surae muscle induced a suppression of the monosynaptic reflex. The intensity of presynaptic inhibition increased, while the intensity of recurrent inhibition decreased. Post fatigue-evoked changes in monosynaptic reflexes and presynaptic inhibition indicate the possibility that high-threshold afferents inhibit group Ia terminals pre-synaptically, which would allow fatigue-induced signals from the muscle to reduce the relevance of proprioceptive feedback. Besides intrasegmental, intersegmental spreading of nociceptive signals was explored. Activation of sensory afferents from dorsal neck muscles by capsaicin induces powerful activation of interneurons located in the cervical spinal cord, as well as a widespread activation of cells in lumbar spinal cord segments.

    The results confirm the pivotal role of small diameter muscle afferents in the orchestration of segmental responses to fatigue and show complex interactions that may lead to limited accuracy of motor output. They also depict processes that may be related to, and even become precursors of chronic muscle pain.

  • 220.
    Kalezic, Ivana
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Bugaychenko, Larisa A.
    Department of Movement Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Kiev, Ukraine.
    Kostyukov, Alexander I.
    Department of Movement Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Kiev, Ukraine.
    Pilyavskii, Alexander I.
    Department of Movement Physiology, Bogomoletz Institute of Physiology, National Academy of Sciences, Kiev, Ukraine.
    Ljubisavljevic, Milos
    Department of Neurophysiology, Institute for Medical Research, Belgrade, Serbia and Montenegro.
    Windhorst, Uwe
    Centre for Musculoskeletal Research, University of Gävle.
    Johansson, Håkan
    Centre for Musculoskeletal Research, University of Gävle.
    Fatigue-related depression of the feline monosynaptic gastrocnemius-soleus reflex2004In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 556, no 1, p. 293-296Article in journal (Refereed)
    Abstract [en]

    In decerebrate cats, changes in the monosynaptic reflex (MSR) of gastrocnemius-soleus (G-S) motoneurones were studied after fatiguing stimulation (FST) of the G-S muscles. Monosynaptic reflexes were evoked by stimulation of Ia fibres in the G-S nerve and recorded from a filament of ventral root (VR) L7. FST (intermittent 40 s(-1) stimulation for 10-12 min) was applied to the distal part of the cut VR S1. FST reduced MSR amplitudes to 0.64 +/- 0.04 (mean +/-s.e.m.) of the prefatigue values. The suppression remained stable for approximately 25 min and then MSR amplitudes gradually returned towards the normal. To test for the involvement of presynaptic and recurrent inhibition, MSRs were conditioned by stimulation of the nerve to the posterior biceps and semitendinosus (PBSt) muscles or a filament of VR L7, respectively. The intensity of presynaptic inhibition (reduction of the normalized value of MSR amplitude during conditioning) increased from 0.19 +/- 0.02 in prefatigue to 0.44 +/- 0.04 within a 5.3-18.2 min interval after FST, followed by a recovery. In contrast, the intensity of recurrent inhibition first diminished from 0.23 +/- 0.02 in prefatigue to 0.15 +/- 0.01 within 15.6-30.1 min after FST and then gradually recovered. Both primary afferent depolarization and the intensity of antidromic discharges in primary afferents increased with the presynaptic inhibition intensity. These results demonstrate a fatigue-related suppression of Ia excitation of synergistic motoneurones, probably arising from the activation of group III and IV afferents. The effects could in part be due to increased presynaptic inhibition, while recurrent inhibition plays a minor role.

  • 221.
    Kalezic, Ivana
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pilyavskii, AI
    Maisky, VA
    Kostyukov, AI
    Windhorst, U
    Johansson, H
    Distinctive pattern of c-fos expression in the feline cervico-lumbar spinal cord after stimulation of vanilloid receptors in dorsal neck muscles2004In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 364, no 2, p. 94-97Article in journal (Refereed)
    Abstract [en]

    In the present study, c-fos expression in the spinal cord has been used as a marker of neuronal activation induced by capsaicin-sensitive sensory afferents from the dorsal neck muscles in cats (n = 6). The number of Fos-immunoreactive neurons, which were revealed using the avidin-biotin-peroxidase method, was significantly increased in the cervical and lumbar spinal cord. In contrast to the control group (n = 3), 2 h after intramuscular capsaicin injection, c-fos expression was more extensive ipsilaterally to the injected side in the C3-C6 segments, and bilaterally in the L4-L6 segments. Most labeled neurons in the cervical spinal cord were small and giant cells, predominantly located in the middle and lateral parts of lamina I and, additionally, at the neck of the dorsal horn (lamina V), i.e., within the zones of termination of high-threshold muscle afferents. The widespread distribution of labeled cells throughout the cervical cord within the intermediate zone (lamina VII) coincided with the sites of last-order premotor interneurons and cells of origin of long crossed and uncrossed descending propriospinal pathways to the lumbar spinal cord. These findings suggest possible mechanisms for spreading of nociceptive signals between cervical and lumbar regions.

  • 222.
    Kalezic, Ivana
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Centre for Musculoskeletal Research, University of Gävle, Umeå, Sweden.
    Steffens, Heinz
    Institute of Physiology, University of Göttingen, Göttingen, Germany.
    Changes in Tetrodotoxin-Resistant C-Fibre Activity during Fatiguing Isometric Contractions in the Rat2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 9, p. e73980-Article in journal (Refereed)
    Abstract [en]

    It is by now well established that tetrodotoxin-resistant (TTX-R) afferent fibres from muscle in the rat exhibit a multisensitive profile, including nociception. TTX-R afferent fibres play an important role in motor control, via spinal and supraspinal loops, but their activation and function during muscle exercise and fatigue are still unknown. Therefore, the specific effect of isometric fatiguing muscle contraction on the responsiveness of TTX-R C-fibres has been investigated in this study. To quantify the TTX-R afferent input we recorded the cord dorsum potential (CDP), which is the result of the electrical fields set up within the spinal cord by the depolarisation of the interneurons located in the dorsal horn, activated by an incoming volley of TTX-R muscle afferents. The changes in TTX-R CDP size before, during and after fatiguing electrical stimulation of the gastrocnemius-soleus (GS) muscle have been taken as a measure of TTX-R C-unit activation. At the end of the fatiguing protocol, following an exponential drop in force, TTX-R CDP area decreased in the majority of trials (9/14) to 0.75 +/- 0.03% (mean +/- SEM) of the pre-fatigue value. Recovery to the control size of the TTX-R CDP was incomplete after 10 min. Furthermore, fatiguing trials could sensitise a fraction of the TTX-R C-fibres responding to muscle pinch. The results suggest a long-lasting activation of the TTX-R muscle afferents after fatiguing stimulation. The role of this behaviour in chronic muscle fatigue in connection with pain development is discussed. Accumulation of metabolites released into the interstitium during fatiguing stimulation might be one of the reasons underlying the C-fibres' long-lasting activation.

  • 223.
    Kalezic, Nebojsa
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Noborisaka, Yuka
    Nakata, Minori
    Crenshaw, Albert G
    Karlsson, Stefan
    Lyskov, Eugene
    Eriksson, Per-Olof
    Umeå University, Faculty of Medicine, Department of Odontology.
    Cardiovascular and muscle activity during chewing in whiplash-associated disorders (WAD)2010In: Archives of Oral Biology, ISSN 0003-9969, E-ISSN 1879-1506, Vol. 55, no 6, p. 447-453Article in journal (Refereed)
    Abstract [en]

    More intense response to chewing in WAD might indicate pronounced vulnerability to dynamic loading of the jaw-neck motor system with increased autonomic reactivity to the test. Premature termination and autonomic involvement without EMG signs of muscle fatigue may indicate central mechanisms behind insufficient endurance during chewing.

  • 224.
    Karlsson, Robin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Barn och ungdomars deltagande i skolidrott och föreningsidrott – en jämlikhetsfråga?: En värdering av kunskapsläget och förslag till aktion för barn och ungdomars hälsa.2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Children and adolescents have the right to be equally teaches and coached in physical education (PE) at school and to be equally treated as all children in sports clubs. Physical activity can be described as all kind of movements that preformed during physical activity. Physical activity can improve physical fitness as well as it has positive effect on concentration, self-esteem and to work towards goals and getting better at planning for the school homework’s. The recommended amount of physical activity for children and adolescents, started by established health organizations, is about 60 minute’s physical activity per day, to prevent unhealthy physical states and to promote current and long term health. However the level of physical activity on children´s leisure time has decreased dramatically in recent decades. This can be explained by increased time spending indoor with computer games, TV and social media through new technologies that been developed in recent decades. This means that physical activity trough PE-classes in school and by participating in sports club. Here, the government in Sweden through the national sports federation (RF), has invested a large amount of money to increase the number of youth participating in physical activities and sports through two economic stakes called Idrottslyftet and Handslaget (www.rf.se). However, these interventions have recently been evaluated with discouraging results. An important question to explore by the future research is whether the children and adolescents who are most inactive during leisure time are the same who are least active and involved in PE-classes in school. In this case, it is urgent that the children and adolescents who are in very high need of physical activity are seen and coached during PE-classes.

     

    This essay is focused on the PE in school and children´s and adolescent’s physical activity and sports at leisure time, all in view of health and equal rights.      

     

    Keywords: Idrottsföreningar, samarbete, samverkan, föreningsidrott, skolidrott, Handslaget, Idrottslyftet, GIH, physical activity, spontanidrott, Children, adolescents, Community Interventions,

  • 225.
    Karlsson, Robin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Finns det någon variation i CMJ som återföljs av förändringar i någon av pulsvariationerna och handstyrkan?2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Introduction

    Successful training is a key for athletes to make progress in their development. Training must not just involve overload, but also must prevent the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement without severe psychological or lasting other negative symptoms. Too much hard exercise or too little sleep can cause overtraining, a condition in which the subject can prevent to be away from the sport for several weeks or months. Previous studies have detected that it is important to avoid overtraining. A reliable method is currently not available to detect the warning signs in time to prevent it.

    AIM:  When physical performance deteriorates with overtraining is the purpose of the current study to determine whether impaired explosive strength performance (CMJ) is related to the change in HRV and static strength (grip strength) between the best and worst test day during one season.

    Purpose and Methods: Variation in CMJ was investigated in eight elite floorball players (four women and four men). Heart rate variability (HRV) was measured using a heart rate monitor. The subjects were in supine position for ten minutes and changed into a standing position for eight minutes when HRV was recorded. After the mentees had performed HRV recording, three CMJ jumps and grip strength test was made where the best result was noted. This jump and grip strength was done to check upper and lower body strength.

    Results: Significant differences were detected in CMJ, HRV, but not in grip strength. In HRV occurred the significance of all the variables, but the most obvious differences were detected in average heart lying/standing and resting heart rate.

    Conclusions: Significant differences were detected in CMJ, HRV but not in the grip strength. Impaired explosive strength (CMJ) is related to changes in HRV, but not static strength.

    Keywords: Heart rate variability, Overreaching, Overtraining.  

  • 226.
    Karlsson, Sjöström, Victoria, Erik
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Metabola syndromet kopplat till fysisk aktivitet och konditionsstatus2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    The development and onset of diseases such as cardiovascular disease (CVD) and Type 2 diabetes are closely linked to genetics and lifestyle factors including physical activity and diet. A cluster of metabolic disorders called the metabolic syndrome (MetS) is a high-risk factor in developing these diseases. Acording to the International diabetes institute, one fourth of the worlds adult population has MetS. These individuals are twice as likely to die from CVDs compared to individuals without MetS. Physical activity (PA) and exercise has been shown to provide a number of positive effects that are considered to reduce the risk of developing sickness and premature mortality among both men and women of all ages, independent of other risk factors.    

    Therefore our objective with this litterature-study was to establish the components of MetS, the relationship between PA, cardiorespiratory fitness and MetS, and the effects of exercise on MetS through intervention-studies.

     

    Results: There are several components included in MetS and to be diagnosed with it you have to have at least three of the following: Abdominal obesity, hypertriglyceridemia, hypertension, abnormal glucose levels and/or low levels of HDL cholesterol. Close connections can be found between PA and CRF, and there are strong indications that an increase in PA and/or CRF have positive effects on the various components in MetS. This is supported by numerous intervention-studies with physical exercise targeting metabolic factors included in MetS.

     

    Conclusion: The results indicate that PA and CRF have an important role to play in the prevention and treatment of the various components included in MetS. These variables can also, to some degree, predict the risk of developing MetS.  

     

    Key words:

    Metabolic syndrome, physical activity, cardiorespiratory fitness, relationship

  • 227.
    Koivumäki, Maria
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Barefoot versus shod running: a review on running economy and biomechanical differences2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 228.
    Korotkov, A.
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Ljubisavljevic, M.
    Thunberg, J.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Kataeva, G.
    Roudas, M.
    Pakhomov, S.
    Radovanovic, S.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lyskov, E.
    Medvedev, S.
    Johansson, H.
    Changes in human regional cerebral blood flow following hypertonic saline induced experimental muscle pain: a positron emission tomography study2002In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 335, no 2, p. 119-123Article in journal (Refereed)
    Abstract [en]

    A positron emission tomography imaging study was performed on 16 healthy volunteers to reveal changes in cortical activation during acute muscle pain induced by intra-muscular injection of hypertonic saline into the left triceps brachii muscle. Changes in regional cerebral blood flow (rCBF) were measured with the use of [(15)O] labelled water during 'Rest1', 'Needle' (insertion of a needle without injection), 'Rest2' and 'Pain' conditions. Differences in rCBF were found in the comparison of Pain and Needle, and Pain and Rest2 conditions, revealing activation of the contralateral insula and putamen. The results are discussed with respect to possible differences in brain processing of muscle and cutaneous noxious inputs.

  • 229.
    Korotkov, Alexander
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Brain processing of experimental muscle pain and its interrelation with proprioception and muscle fatigue: positron emission tomography study2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chronic muscle pain is a significant medical and social problem and better understanding of the pathophysiological mechanisms involved is an important requirement for further development of diagnostics, treatment and rehabilitation methods. Experimental imaging studies have investigated functional neuroanatomy of different pain components. However, several aspects of brain mechanisms underlying brain processing of muscle pain remain unclear.

    The general goal of the present thesis was to study functional brain anatomy of systems underlying perception of muscle pain, processing of proprioceptive information and maintenance of fatiguing muscle contractions with an emphasize on their possible interrelations.

    Four series of experiment were carried out. Using an injection of hypertonic saline (HS) into the m. triceps to induce pain comparable with clinical muscle pain a significant activation of insula and putamen as well as decrease of activity in the temporal and occipital cortex in comparison with control stimulation were revealed. An advanced model of prolonged muscle pain were provided by the infusion of the HS during 20 minutes into m. erector spinae A complex dynamics of brain activity during the habituation to nociceptive stimulation was shown: initial activation of insula changed to decrease of activity in this and several other cortical areas. A conjunction analysis identified activations jointly significant in both experiments (despite localization of HS nociceptive stimulation) in the right insula, occipital and left parietal cortical areas. The study of brain activity in response to different modalities of prorioceptive inputs – passive movements, kinesthetic illusions and muscle vibration showed corresponding different patterns of activation in motor and somatosenory areas and temporal areas. Finally, the study of sustained isometric muscle contractions of various force levels and durations revealed that muscle fatigue is associated with contralateral activation of the motor and somatosensory areas and temporal areas and bilateral activation in the supplementary motor areas and cingular cortex, indicating that increased efforts needed to maintain required force and its eventual breakdown with fatigue might induce activation of additional cortical areas. Analysis of data obtained in all experimental series revealed that insula, secondary somatosensory and auditory areas are activated during both perception of muscle pain and processing of somatosensory afferentation.

    In conclusion, this thesis has elucidated brain processing of muscle pain showing distributed, bilateral patterns comprised of activated structures predominantly attributed to the medial pain system and deactivated structures. Furthermore, initial and late phases of tonic muscle pain are associated with different brain reactions, namely initial activation of the insula followed by a significant bilateral decrease of activity at the late stage. Area of brain cortex located near lateral sulcus and comprised of secondary somatosensory cortex, posterior part of the insula and adjacent auditory cortex is engaged in the perception of muscle pain and processing of somatosensory afferentation as well as maintenance of fatiguing muscle contractions.

  • 230.
    Korotkov, Alexander
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Radovanovic, Sasa
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Ljubisavljevic, Milos
    Lyskov, Eugene
    Kataeva, Galina
    Roudas, Marina
    Pakhomov, Sergey
    Thunberg, Johan
    Medvedev, Sviatoslav
    Johansson, Håkan
    Comparison of brain activation after sustained non-fatiguing and fatiguing muscle contraction: a positron emission tomography study.2005In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 163, no 1, p. 65-74Article in journal (Refereed)
    Abstract [en]

    The concept of fatigue refers to a class of acute effects that can impair motor performance, and not to a single mechanism. A great deal is known about the peripheral mechanisms underlying the process of fatigue, but our knowledge of the roles of the central structures in that process is still very limited. During fatigue, it has been shown that peripheral apparatus is capable of generating adequate force while central structures become insufficient/sub-optimal in driving them. This is known as central fatigue, and it can vary between muscles and different tasks. Fatigue induced by submaximal isometric contraction may have a greater central component than fatigue induced by prolonged maximal efforts. We studied the changes in regional cerebral blood flow (rCBF) of brain structures after sustained isometric muscle contractions of different submaximal force levels and of different durations, and compared them with the conditions observed when the sustained muscle contraction becomes fatiguing. Changes in cortical activity, as indicated by changes in rCBF, were measured using positron emission tomography (PET). Twelve subjects were studied under four conditions: (1) rest condition; (2) contraction of the m. biceps brachii at 30% of MVC, sustained for 60 s; (3) contraction at 30% of MVC, sustained for 120 s, and; (4) contraction at 50% of MVC, sustained for 120 s. The level of rCBF in the activated cortical areas gradually increased with the level and duration of muscle contraction. The fatiguing condition was associated with predominantly contralateral activation of the primary motor (MI) and the primary and secondary somatosensory areas (SI and SII), the somatosensory association area (SAA), and the temporal areas AA and AI. The supplementary motor area (SMA) and the cingula were activated bilaterally. The results show increased cortical activation, confirming that increased effort aimed at maintaining force in muscle fatigue is associated with increased activation of cortical neurons. At the same time, the activation spread to several cortical areas and probably reflects changes in both excitatory and inhibitory cortical circuits. It is suggested that further studies aimed at controlling afferent input from the muscle during fatigue may allow a more precise examination of the roles of each particular region involved in the processing of muscle fatigue.

  • 231. Kostyukov, AI
    et al.
    Kalezic, Ivana
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Serenko, SG
    Ljubisavljevic, M
    Centre for Musculoskeletal Research, National Institute for Working Life - Umeå.
    Windhorst, U
    Centre for Musculoskeletal Research, National Institute for Working Life - Umeå.
    Johansson, H
    Centre for Musculoskeletal Research, National Institute for Working Life - Umeå.
    Spreading of fatigue-related effects from active to inactive parts in the medial gastrocnemius muscle of the cat2002In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 86, no 4, p. 295-307Article in journal (Refereed)
    Abstract [en]

    In the medial gastrocnemius muscle of the decerebrate cat, the spatial spread of fatigue between active and inactive muscle parts was studied. Conditioning fatiguing stimulation (CFS) was applied to a part of the muscle to test whether it had an effect on the contraction efficiency in an unstimulated part. To exclude somato-sympathetic reflexes during CFS, a full rhizotomy of the lumbo-sacral spinal cord was performed. The same ipsilateral ventral root, either L7 or S1, was divided into seven filaments, one of which was used for the test stimulation, and four or five for CFS. The CFS consisted of 12 s sessions of distributed stimulation of five (or four) filaments at a rate of 40 s(-1), the sessions were repeated, every 40 s, 15 or more times. The test consisted of 12 s of regular stimulation at a rate of 10 s(-1), preceded and followed by a single stimulus. The tests applied just after CFS showed a strong decline of both tension and electromyogram (EMG), amounting to only [mean (SD)] 0.45 (0.18) and 0.51 (0.19) (n = 15), respectively, of the corresponding values in the tests before CFS. It thus turned out that depressive fatigue-related effects could spread within the muscle. At the same time, control reactions recorded in the lateral gastrocnemius during stimulation of its cut nerve did not change. Subsequent repetitions of the tests usually revealed a tendency towards restoration. The EMG reactions recovered more quickly than tension. The depression of EMG after CFS was accompanied by a slowing of the constituent M-waves; their latencies decreased during restoration. Distinct changes in the systemic blood pressure were observed during CFS. These changes were usually correlated well with muscle tension changes. The factors possibly underlying the observed effects may include diffusion of metabolites from active to inactive muscle fibres, lowering of the efficiency of neuro-muscular transmission due to squeezing of efferent motor terminals and changes in outer metabolite content, as well as local hypoxia due to increases in intramuscular pressure.

  • 232. Kristoffersen, Mads
    et al.
    Öhberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Johnston, Christopher
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Neovascularisation in chronic tendon injuries detected with colour Doppler ultrasound in horse and man: implications for research and treatment2005In: Knee Surg Sports Traumatol Arthrosc, ISSN 0942-2056, Vol. 13, no 6, p. 505-508Article in journal (Refereed)
  • 233. Larsson, Anders
    et al.
    Svensson, Michael B
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Ronquist, Göran
    Åkerfeldt, Torbjörn
    Life style intervention in moderately overweight individuals is associated with decreased levels of cathepsins L and S in plasma2014In: Annals of Clinical and Laboratory Science, ISSN 0091-7370, E-ISSN 1550-8080, Vol. 44, no 3, p. 283-285Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Adipose tissue cells produce cathepsins L and S, which have proatherogenic effects. Obesity is strongly linked to atherogenesis, cardiovascular morbidity, and mortality. OBJECTIVE: The aim of the present study was to see if life style interventions/weight reduction could decrease cathepsin L and S levels in blood plasma. METHOD: Study subjects (n=31) were recruited to a life style intervention program aiming at increased physical activity, more healthy eating habits, and weight reduction for most of the participants. Blood samples were collected at inclusion and after 4 and 8 weeks. RESULTS: Cathepsin L was significantly reduced at 4 weeks (p<0.0001) and 8 weeks (p=0.0004). A similar reduction was also seen for cathepsin S at 4 weeks (p=0.03) and 8 weeks (p=0.008). No significant change in fractalkine values was observed at 4 weeks (p=0.58), but a significant increase was apparent at 8 weeks (p=0.0002). CONCLUSION: The intervention program resulted in significant reductions of cathepsin L and S levels in plasma after 4 and 8 weeks of intervention.

  • 234.
    Larsson, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pulsjakten: En fyra månaders träningsintervention2012Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I dagens stillasittande samhälle, där individer är allt mindre fysiskt aktiva till följd av alla moderna bekvämligheter ökar risken för en rad sjukdomstillstånd som potentiellt kan leda till en förtidig död. Den svenska befolkningen blir allt fetare och rör på sig i mindre utsträckning. Något som skulle kunna ändras om vi visste vad som motiverar till fysisk aktivitet.

    I denna studie genomgick 113 personer, anställda på Länsförsäkringar, ett enkelt steptest. Efter testet hade de sedan fyra månader på sig att träna innan de genomgick ett återtest, som var en exakt kopia på test ett, för att se hur stor förändring som gick att få genom träning gällande puls och vikt. Deltagarna delades in i tre grupper utefter hur mycket de ökade sin träningsmängd mellan testen: en kontrollgrupp, en grupp med liten ökning av den fysiska aktiviteten och en grupp med en stor ökning av den fysiska aktiviteten. Det visade sig att ökad träning var av betydelse för att förbättra konditionen. Personerna i gruppen med stor ökning hade en större pulssänkning än de andra grupperna men det fanns även en sänkning av pulsen för gruppen med liten ökning av den fysiska aktiviteten. I gruppen med liten ökning av den fysiska aktiviteten fanns även en viktminskning.

  • 235.
    Larsson, P U
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Wadell, K M E
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Jakobsson, E J I
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Burlin, L U
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, K B
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Validation of the MetaMax II portable metabolic measurement system.2004In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 25, no 2, p. 115-123Article in journal (Refereed)
  • 236.
    Larsson, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Burlin, Lennart
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Jakobsson, Erkki
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Analysis of performance in orienteering with treadmill tests and physiological field tests using a differential global positioning system.2002In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 20, no 7, p. 529-535Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine the physiological responses to orienteering by examining the interrelationships between the information provided by a differential global positioning system (dGPS) about an orienteer's route, speed and orienteering mistakes, portable metabolic gas analyser data during orienteering and data from incremental treadmill tests. Ten male orienteers completed a treadmill threshold test and a field test; the latter was performed on a 4.3 km course on mixed terrain with nine checkpoints. The anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio, onset of blood lactate accumulation and peak oxygen uptake (VO2peak) were determined from the treadmill test. Time to complete the course, total distance covered, mean speed, distance and timing of orienteering mistakes, mean oxygen uptake, mean relative heart rate, mean respiratory exchange ratio and mean running economy were computed from the dGPS data and metabolic gas analyser data. Correlation analyses showed a relationship between a high anaerobic threshold and few orienteering mistakes (r = - 0.64, P < 0.05). A high threshold of decompensated metabolic acidosis and VO2peak were related to a fast overall time (r = -0.70 to -0.72, P < 0.05) and high running speed (r = 0.64 to 0.79, P < 0.05 and P < 0.01, respectively), and were thus the best predictors of performance.

  • 237.
    Larsson, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, K
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Body composition and performance in cross-country skiing.2008In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 29, no 12, p. 971-5Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the relationships between body composition and performance in cross-country skiing. Ten male college-aged elite cross-country skiers (17.9 yrs; S 1.0 yrs) participated in a 5.6-km cross-country skiing time trial and in dual energy X-ray absorptiometry (DXA, Lunar DPX-L, Madison, WI, USA) body composition measurements. A differential global positioning system (dGPS, GPS 12 CX, Garmin Int. Inc., Olathe, KS, USA; RXMAR 2, Aztec SA, Strasbourg, France) was used to compute speed in different sections of the course. Spearman correlation analyses were applied. Total body weight and absolute lean body mass were significantly related to final time (r = - 0.721; p < 0.05 and - 0.830; p < 0.01, respectively). Absolute lean arm mass (kg) was negatively correlated to final time (r = - 0.648; p < 0.05) and the relative lean arm mass was significantly related to speed mainly in uphill sections (r = 0.636 to 0.867; p < 0.05 to p < 0.01). We suggest that large amounts of lean body mass, especially in the arms, seem to be of great importance for cross-country skiing performance.

  • 238. Larsson, Peter
    et al.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Combined metabolic gas analyser and dGPS analysis of performance in cross-country skiing.2005In: J Sports Sci, ISSN 0264-0414, Vol. 23, no 8, p. 861-70Article in journal (Refereed)
  • 239.
    Larsson, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    The use of dGPS and simultaneous metabolic measurements during orienteering.2001In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 33, no 11, p. 1919-1924Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The Global Positioning System (GPS) is a satellite-based system for navigation. With this system, it is possible to pinpoint a subject's location on earth and to display the speed of movement. With the use of differentiation (dGPS), the accuracy of the GPS position and speed measurements can be improved. Our purpose was to investigate whether it would be possible to relate dGPS data with physiological variables in a field test and thus achieve a more controlled field test and hence improve the value of sport-specific testing. METHODS: 10 male orienteers were equipped with a portable metabolic gas analyzer and a differential Global Positioning System (dGPS). A field test was performed on a 4.3-km orienteering course. Oxygen uptake, carbon dioxide excretion, and heart rate were determined every 10 s. Speed was calculated by Doppler shift every 2 s and by differences in dGPS time and position. Validation of dGPS position, distance, and speed measurements was made on two fixed positions and on a 115-m straight asphalt road. RESULTS: The orienteers' route was visualized by the dGPS equipment. Detailed analysis of running speed in different sections of the course was made possible. Further, it was possible to relate each physiological data to the location of the subject. The correlation coefficient between speed measured by dGPS and speed measured by chronometry was r = 0.9995-0.9996. The mean errors of distance and position measurements were 0.04-0.7% and 1.94-2.13 m, respectively. CONCLUSION: dGPS was shown to be a method that could give detailed information about a subject's speed and position. It was further demonstrated that physiological variables could be related to dGPS data.

  • 240.
    Larsson, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Olofsson, P
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Jacobsson, Erkki
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Burlin, Lennart
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Clinical Physiology.
    Physiological predictors of performance in cross-country skiing from treadmill tests in male and female subjects.2002In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 12, no 6, p. 347-353Article in journal (Refereed)
    Abstract [en]

    In order to study which parameter that best corresponds to performance during cross-country skiing, seven male and nine female cross-country skiers were tested with treadmill tests. Parameters measured or computed by metabolic gas measurements were the anaerobic threshold (AT), threshold of decompensated metabolic acidosis (TDMA), the exercise intensity where the Respiratory exchange ratio reaches 1.0 (R = 1) and peak oxygen (O2) uptake (VO2peak). Onset of blood lactate accumulation (OBLA, 4 mmol.l-1 blood lactate) was also measured. The various parameters were measured in percentage of maximal heart rate, percentage of peak O2 uptake, VO2 ml.kg-1.min-1, VO2 ml.min-1.kg-2/3 and VO2 l.min-1. Results from four large competitions were also collected to rank the subjects. With correlation analysis, it was revealed that in male subjects a high OBLA was associated with good ranking results (r = (-0.829) - (-0.964); P < 0.05-0.001). In female subjects, the best association with competition results was found for R = 1 (r = (-0.715) - (-0.810); P < 0.05). Concerning VO2 measurements, for male subjects the unit l.min-1 is suggested to be used and for female subjects either the units l.min-1, ml.min-1.kg-2/3, or ml.kg-1.min-1 could be used when predicting performance in cross-country skiing. In conclusion, treadmill tests can be used for the prediction of performance in cross-country skiing. Further, various parameters from treadmill tests in men and women are best used as predictors of performance in cross-country skiing.

  • 241.
    Larsson, Petter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Fysiologiska kvaliteter hos manliga tävlingscyklister och effekten av högintensiv intervallträning2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract Road cycling is well established and has always been described as a highly endurance sport. To be able to compete in such a demanding sport the physiology of the athletes needs to be greatly developed. This review will focus on high intensity interval training and its impact on the physiological characteristics of competitive road cyclists. The main difference between different levels of competitive road cyclists seems to be the capacity to maintain a high sub maximal power output over a long period of time in order to succeed. High intensity interval training, from 30 seconds to 5 minutes, leads to improved VO2peak, aerobic peak power and time trial performance. The intensities used during these intervals are all based on the cyclists aerobic power output. Despite these findings, very few researches have studied the impact of interval training among professional road cyclists. Future research should therefore make us of mobile power meter units as a part to implement professional road cyclists in studies concerning interval training. In that way the cyclists will be able to train under their regularly routine in their ordinary training environment. Keywords: Competitive road cyclists, interval training, physiological characteristics, power meter. 

  • 242.
    Li, Ming G
    et al.
    Umeå University, Faculty of Medicine, Integrative Medical Biology. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Increased bone turnover as reflected by biochemical markers in patients with potentially unstable fixation of the tibial component.2004In: Arch Orthop Trauma Surg, ISSN 0936-8051, Vol. 124, no 6, p. 404-9Article in journal (Refereed)
  • 243.
    Lind, Bengt
    et al.
    Umeå University, Faculty of Medicine, Radiation Sciences, Diagnostic Radiology.
    Ohberg, Lars
    Umeå University, Faculty of Medicine, Radiation Sciences, Diagnostic Radiology.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Sclerosing polidocanol injections in mid-portion Achilles tendinosis: remaining good clinical results and decreased tendon thickness at 2-year follow-up.2006In: Knee Surg Sports Traumatol Arthrosc, ISSN 0942-2056, Vol. 14, no 12, p. 1327-32Article in journal (Refereed)
  • 244.
    Lindberg, Ann-Sofie
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Firefighters' physical work capacity2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The overall aim of this thesis was to identify valid, simple, and inexpensive physical tests that can be used for evaluation of firefighters’ physical work capacity. Paper I included fulltime- and part-time firefighters (n = 193), aged 20-60 years. Perceived physical demands of firefighting work tasks were ranked, and comparisons between subject groups rating were done with the Mann Whitney U-test and Binominal test. Papers II and III included male firefighters and civilian men and women (n = 38), aged 24-57 years. Laboratory and field tests of aerobic fitness, muscle strength and endurance, balance, and simulated firefighting work tasks were performed. Physical capacity comparisons between subject groups were done and bivariate correlations between physical tests and work capacity in the simulated firefighting work tasks analyzed. Paper IV included the same subjects as in Paper II-III (training-set), and additional 90 subjects (prediction-set), aged 20-50 years. Laboratory and field tests of aerobic fitness, muscle strength and endurance and balance, and simulated firefighting work tasks were included. Data from the training-set was used to build models for prediction of firefighters’ physical work capacity, using multivariate statistic. The prediction-set was used to externally validate the selected models. Several work tasks were rated as physically demanding and significant differences (p < 0.05) in ratings were found between full-time and part-time firefighters (Paper I). Significant differences were found between subject groups in physical capacity, and work capacity (p < 0.01) (Paper II-IV). Both laboratory and field tests were significantly (p < 0.01) correlated with work capacity time (Paper II-III). The prediction (R2) and predictive power (Q2) of firefighters’ work capacity (Carrying hose baskets upstairs, Hose pulling, Demolition at or after a fire, Victim rescue, and Carrying hose baskets over terrain) was R2 = 0.74 to 0.91, and Q2 = 0.65 to 0.85, and the external validation ranged between R2: 0.38 to 0.80 (Paper IV).

    In conclusion, rowing 500 m (s), maximal handgrip strength (kg), endurance bench press (n), running 3000 m (s and s scaled to body weight) upright barbell row (n) and standing broad jump (m) together provides valid information about firefighters’ physical work capacity. 

  • 245.
    Lindberg, Ann-Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Gavhed, Desiree
    Karolinska Institutet.
    Oksa, Juha
    Antti, Henrik
    Multivariate statistical assessment of predictors of firefighters' muscular and aerobic work capacityArticle in journal (Refereed)
  • 246.
    Lindberg, Ann-Sofie
    et al.
    Winternet, Boden.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Hammarström, Daniel
    Högskolan Dalarna, Falun.
    Oksa, Juha
    Finnish Institute of Occupational Health, Oulu Centre of Expertise for Health and Work Ability Physical Work Capacity team Aapistie.
    Tonkonogi, Michail
    Högskolan Dalarna, Falun.
    Maximal work capacity and performance depends warm-up procedure and environmental but not inspired air temperatures2012In: Journal of Exercise Physiology - Online, ISSN 1097-9751, E-ISSN 1097-9751, Vol. 15, no 1, p. 40-46Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to compare peak (VO2 peak) and maximal (VO2 max) oxygen uptake, physical performance, and lactate accumulation [la-] in warm versus cold environments. The influence of inhaled air temperature and different warm up modes on these variables as well as arterial oxygen saturation (SaO2%) and pulmonary function were also studied. Two studies were performed. In study A, 10 males performed maximal exercise tests on a bicycle at +20°C and -12°C. In study B, 8 elite cross-country skiers performed maximal cross-country skiing tests at +13.7ºC. Different warm up modes (continuous and intermittent) and different temperatures of the inhaled air (-8°C and +13°C) were used.  In study A, we found significantly higher VO2 peak, peak carbon dioxide (VCO2 peak), peak ventilation (VE peak) and respiratory exchange ratio (RER) in +20°C compared to -12°C. In study B, we found significantly lower SaO2% at the end compared to the beginning of the maximal performance test. Time to exhaustion (Tex) was significantly longer using intermittent warm up irrespectively of inhaled air temperature. In conclusion, we found that VO2 max was affected by different environmental temperatures but not by different temperatures of the inhaled air and that intermittent warm up increased Tex without affecting VO2 max.

  • 247.
    Lindberg, Ann-Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Winternet, Boden, Sweden.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Winternet, Boden, Sweden.
    Oksa, Juha
    Gavhed, Desiree
    Self-rated physical loads of work tasks among firefighters2014In: International Journal of Occupational Safety and Ergonomics, ISSN 1080-3548, E-ISSN 2376-9130, Vol. 20, no 2, p. 309-321Article in journal (Refereed)
    Abstract [en]

    Objectives: The present study sought to identify firefighters' rated physical demands for the most frequently occuring work tasks and to determine if the ratings differed between full-time and part-time firefighters to help create a basis for the development of physical employment tests for firefighters.

    Methods: An extensive questionnaire was completed by 125 and 68 firefighters in 2000 and 2010, respectively. The data were analysed with the Mann-Whitney U test and binominal test and ranked on the basis of the responses in each category.

    Results: Significant differences were seen between the full-time and part-time firefighters. The work tasks rated as the most physically strenous in terms of aerobic fitness, muscle strength, work posture and body control by most responders were smoke diving upstairs (carrying a hose), victim rescue in different ways, carrying a stretcher over terrain and pulling a hose.

    Conclusions: Physically strenous work tasks should be included in the end-point performance variables used to select physical performance tests for firefighters. The part-time firefighters with no experience in several of the work tasks suggests that work-related exercises are important if both groups of firefighters are expected to do similar work.

  • 248.
    Lindberg, Ann-Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Oksa, Juha
    Physical Work Capacity-team, Finnish Institute of Occupational Health, Oulu, Finland.
    Gavhed, Désirée
    Department of Women’s and Children’s Health, Karolinska Institute.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Field tests for evaluating the aerobic work capacity of firefighters2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 7, p. e68047-Article in journal (Refereed)
    Abstract [en]

    Working as a firefighter is physically strenuous, and a high level of physical fitness increases a firefighter's ability to cope with the physical stress of their profession. Direct measurements of aerobic capacity, however, are often complicated, time consuming, and expensive. The first aim of the present study was to evaluate the correlations between direct (laboratory) and indirect (field) aerobic capacity tests with common and physically demanding firefighting tasks. The second aim was to give recommendations as to which field tests may be the most useful for evaluating firefighters' aerobic work capacity. A total of 38 subjects (26 men and 12 women) were included. Two aerobic capacity tests, six field tests, and seven firefighting tasks were performed. Lactate threshold and onset of blood lactate accumulation were found to be correlated to the performance of one work task (rs = -0.65 and -0.63, p<0.01, respectively). Absolute (mL·min(-1)) and relative (mL·kg(-1)·min(-1)) maximal aerobic capacity was correlated to all but one of the work tasks (rs = -0.79 to 0.55 and -0.74 to 0.47, p<0.01, respectively). Aerobic capacity is important for firefighters' work performance, and we have concluded that the time to row 500 m, the time to run 3000 m relative to body weight (s·kg(-1)), and the percent of maximal heart rate achieved during treadmill walking are the most valid field tests for evaluating a firefighter's aerobic work capacity.

  • 249.
    Lindberg, Ann-Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Winternet, Boden.
    Oksa, Juha
    Physical Work Capacity Team, Finnish Institute of Occupational Health, Oulu, Finland.
    Malm, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Laboratory or field tests for evaluating firefighters' work capacity2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, p. e91215-Article in journal (Refereed)
    Abstract [en]

    Muscle strength is important for firefighters work capacity. Laboratory tests used for measurements of muscle strength, however, are complicated, expensive and time consuming. The aims of the present study were to investigate correlations between physical capacity within commonly occurring and physically demanding firefighting work tasks and both laboratory and field tests in full time (N = 8) and part-time (N = 10) male firefighters and civilian men (N = 8) and women (N = 12), and also to give recommendations as to which field tests might be useful for evaluating firefighters' physical work capacity. Laboratory tests of isokinetic maximal (IM) and endurance (IE) muscle power and dynamic balance, field tests including maximal and endurance muscle performance, and simulated firefighting work tasks were performed. Correlations with work capacity were analyzed with Spearman's rank correlation coefficient (rs). The highest significant (p<0.01) correlations with laboratory and field tests were for Cutting: IE trunk extension (rs = 0.72) and maximal hand grip strength (rs = 0.67), for Stairs: IE shoulder flexion (rs = −0.81) and barbell shoulder press (rs = −0.77), for Pulling: IE shoulder extension (rs= −0.82) and bench press (rs = −0.85), for Demolition: IE knee extension (rs = 0.75) and bench press (rs = 0.83), for Rescue: IE shoulder flexion (rs = −0.83) and bench press (rs = −0.82), and for the Terrain work task: IE trunk flexion (rs = −0.58) and upright barbell row (rs = −0.70). In conclusion, field tests may be used instead of laboratory tests. Maximal hand grip strength, bench press, chin ups, dips, upright barbell row, standing broad jump, and barbell shoulder press were strongly correlated (rs≥0.7) with work capacity and are therefore recommended for evaluating firefighters work capacity.

  • 250.
    Lindblad Berkhout, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. TNO Work and Employment, Polarisavenue 151, 2130 AS Hoofddorp, The Netherlands.
    Hendriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Bongers, Paulien
    The effect of using a laptopstation compared to using a standard laptop PC on the cervical spine torque, perceived strain and productivity2004In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 35, no 2, p. 147-152Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to assess the effect of using a laptopstation and a laptop PC and how this difference in work set-up affected the mechanical load on the neck (C7-Th1 segment). the subjective evaluation of strain on the neck and productivity. Ten healthy male students at Umea University, Sweden with in average of 10 years of PC work experience and ail average of 18 months of laptop PC work experience participated in the study. For each research subject measurements were divided into two parts; sitting working at the ErgoQ laptopstation in test situation A, and sitting working at a conventional laptop PC, test situation B. Each part took 4 h and was scheduled on two consecutive days. Photography and biomechanical analysis was used to calculate the torque at the neck. To examine perceived strain the Borg Scale was used and to assess performance a productivity score was calculated. The results in the study demonstrated a significant (p<0.05) difference with the use of the laptopstation resulting in decreased torque at the C7-Th1 segment, less perceived strain at the neck and a higher productivity score. A conclusion, the results of the study confirm the importance of adjustable work tools that recognize anthropometric differences and biomechanics to meet the needs of individual customers during continuous visual display terminal work.

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