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Malm, Christer B.
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Publications (10 of 47) Show all publications
Jakobsson, J. & Malm, C. (2019). Maximal Lactate Steady State and Lactate Thresholds in the Cross-Country Skiing Sub-Technique Double Poling. International Journal of Exercise Science, 12(2), 57-68
Open this publication in new window or tab >>Maximal Lactate Steady State and Lactate Thresholds in the Cross-Country Skiing Sub-Technique Double Poling
2019 (English)In: International Journal of Exercise Science, ISSN 1939-795X, Vol. 12, no 2, p. 57-68Article in journal (Refereed) Published
Abstract [en]

The response of blood lactate concentration (BLC) to exercise is a commonly used approach to set training intensities and to determine the anaerobic threshold, which are important in evaluation of endurance exercise performance. The maximal lactate steady state (MLSS) is defined as the highest workload or BLC that can be maintained without continual lactate accumulation over time. The aim of this study was to investigate MLSS in the cross-country skiing sub-technique double poling and to assess the validity of a fixed blood lactate threshold (OBLAand the 45° tangent of the lactate curve). Eight well-trained cross-country skiers (age = 27.6±8.8 years [mean±SD], body mass = 73.9±6.2 kg, height = 179.3±7.0 cm) performed an incremental test to determine OBLA and Individual Anaerobic Threshold (IAnT) and several constant workload tests of 30 min to determine the MLSS. Lactate concentration at MLSS in double poling was 6.7±1.3 mmol·L-1 which was significantly higher compared to OBLA(p<0.001) and IAnT (p<0.01). Despite significant correlations in velocities between MLSS-IAnT and MLSS-OBLA(r=0.95/0.95, p<0.001), significant (p<0.01) differences between MLSS (21.4±2.8 km·h-1) versus IAnT (20.6±3.6 km·h-1) and OBLA(19.9±3.0 km·h-1) was observed. It was concluded that both OBLA and IAnT underestimate MLSS in double poling. A fixed value of 7 mmol·L-1 would be more appropriate in lactate testing of cross-country skiers using the double poling technique, yet dissuaded because of intra-individual variations. Direct determination of MLSS is the recommended approach for useful exercise thresholds, important for training interventions in elite cross-country skiers.

Keywords
Onset of blood lactate, exercise test, submaximal exercise, exercise intensity, exercise prescription, lactate kinetics, anaerobic threshold
National Category
Sport and Fitness Sciences
Research subject
Sports Medicine
Identifiers
urn:nbn:se:umu:diva-155369 (URN)
Available from: 2019-01-14 Created: 2019-01-14 Last updated: 2019-01-14Bibliographically approved
Malm, C. B., Jakobsson, J. & Isaksson, A. (2019). Physical Activity and SportsReal Health Benefits: A Review with Insight into the Public Health of Sweden. Sports, 7(5), Article ID 127.
Open this publication in new window or tab >>Physical Activity and SportsReal Health Benefits: A Review with Insight into the Public Health of Sweden
2019 (English)In: Sports, ISSN 2075-4663, Vol. 7, no 5, article id 127Article, review/survey (Refereed) Published
Abstract [en]

Positive effects from sports are achieved primarily through physical activity, but secondary effects bring health benefits such as psychosocial and personal development and less alcohol consumption. Negative effects, such as the risk of failure, injuries, eating disorders, and burnout, are also apparent. Because physical activity is increasingly conducted in an organized manner, sport's role in society has become increasingly important over the years, not only for the individual but also for public health. In this paper, we intend to describe sport's physiological and psychosocial health benefits, stemming both from physical activity and from sport participation per se. This narrative review summarizes research and presents health-related data from Swedish authorities. It is discussed that our daily lives are becoming less physically active, while organized exercise and training increases. Average energy intake is increasing, creating an energy surplus, and thus, we are seeing an increasing number of people who are overweight, which is a strong contributor to health problems. Physical activity and exercise have significant positive effects in preventing or alleviating mental illness, including depressive symptoms and anxiety- or stress-related disease. In conclusion, sports can be evolving, if personal capacities, social situation, and biological and psychological maturation are taken into account. Evidence suggests a dose-response relationship such that being active, even to a modest level, is superior to being inactive or sedentary. Recommendations for healthy sports are summarized.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
youth, adolescent, elderly, quality of life, relative age effect, exercise, strength and cnditioning
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-161470 (URN)10.3390/sports7050127 (DOI)000470957300032 ()31126126 (PubMedID)
Available from: 2019-07-09 Created: 2019-07-09 Last updated: 2019-07-09Bibliographically approved
Nilsson, R., Lindberg, A.-S., Theos, A., Ferguson, R. A. & Malm, C. (2018). Aerobic Variables for Prediction of Alpine Skiing Performance: A Novel Approach. Sports Medicine International Open, 2(4), E105-E112
Open this publication in new window or tab >>Aerobic Variables for Prediction of Alpine Skiing Performance: A Novel Approach
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2018 (English)In: Sports Medicine International Open, ISSN 2367-1890, Vol. 2, no 4, p. E105-E112Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to investigate the predictive power of aerobic test results and anthropometric variables on FIS-ranking of junior elite alpine skiers. Results from twenty-three male and female adolescent elite alpine skiers from two seasons were included in the multivariate statistical models. Physical work capacity was determined by V̇O2peak, blood lactate concentration ([HLa]b), and heart rate (HR) during ergometer cycling. Anthropometric variables were body stature, body weight and calculated BMI. No significant correlation between competitive performance and aerobic work capacity or anthropometric data was observed neither in male nor female adolescent skiers. Pre-season physical tests and anthropometric data could therefore not predict end-season FIS-ranking. The best regression (R2) and prediction (Q2) models of FIS slalom (SL) and giant slalom (GS) rank reached R2=0.51 to 0.86, Q2=−0.73 to 0.18, indicating no valid models. This study could not establish V̇O2peak and other included variables as predictors of competitive performance. When combining results from commonly used tests for alpine skiers, and applying multivariate statistical models, investigated tests seems of limited used for athletes, coaches, and ski federations. Performance-specific pre-season tests must be developed and validated for prediction of performance and guidance of exercise training.

Place, publisher, year, edition, pages
Georg Thieme Verlag KG, 2018
Keywords
exercise testing, athletic performance, FIS points, multivariate statistics, V̇O2max
National Category
Sport and Fitness Sciences
Research subject
Sports Medicine
Identifiers
urn:nbn:se:umu:diva-154284 (URN)10.1055/a-0655-7249 (DOI)30539126 (PubMedID)
Available from: 2018-12-14 Created: 2018-12-14 Last updated: 2019-05-22Bibliographically approved
Malm, C. & Isaksson, A. (2017). Idrott: en viktig faktor för fysisk och psykisk hälsa. In: JohanFaskunger, Paul Sjöblom (Ed.), Idrottens samhällsnytta: en vetenskaplig översikt av idrottsrörelsens mervärden för individ och samhälle (pp. 21-39). Stockholm: Riksidrottsförbundet
Open this publication in new window or tab >>Idrott: en viktig faktor för fysisk och psykisk hälsa
2017 (Swedish)In: Idrottens samhällsnytta: en vetenskaplig översikt av idrottsrörelsens mervärden för individ och samhälle / [ed] JohanFaskunger, Paul Sjöblom, Stockholm: Riksidrottsförbundet , 2017, , p. 229p. 21-39Chapter in book (Other academic)
Place, publisher, year, edition, pages
Stockholm: Riksidrottsförbundet, 2017. p. 229
Series
FoU-rapport ; 2017:1
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-153080 (URN)978-91-87385-19-3 (ISBN)
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2019-01-16Bibliographically approved
Malm, C. B., Khoo, N. S., Granlund, I., Lindstedt, E. & Hult, A. (2016). Autologous Doping with Cryopreserved Red Blood Cells - Effects on Physical Performance and Detection by Multivariate Statistics. PLoS ONE, 11(6), Article ID e0156157.
Open this publication in new window or tab >>Autologous Doping with Cryopreserved Red Blood Cells - Effects on Physical Performance and Detection by Multivariate Statistics
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2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 6, article id e0156157Article in journal (Refereed) Published
Abstract [en]

The discovery of erythropoietin (EPO) simplified blood doping in sports, but improved detection methods, for EPO has forced cheating athletes to return to blood transfusion. Autologous blood transfusion with cryopreserved red blood cells (RBCs) is the method of choice, because no valid method exists to accurately detect such event. In endurance sports, it can be estimated that elite athletes improve performance by up to 3% with blood doping, regardless of method. Valid detection methods for autologous blood doping is important to maintain credibility of athletic performances. Recreationalmale (N = 27) and female (N = 11) athletes served as Transfusion (N = 28) and Control (N = 10) subjects in two different transfusion settings. Hematological variables and physical performance were measured before donation of 450 or 900 mL whole blood, and until four weeks after re-infusion of the cryopreserved RBC fraction. Blood was analyzed for transferrin, iron, Hb, EVF, MCV, MCHC, reticulocytes, leucocytes and EPO. Repeated measures multivariate analysis of variance (MANOVA) and pattern recognition using Principal Component Analysis (PCA) and Orthogonal Projections of Latent Structures (OPLS) discriminant analysis (DA) investigated differences between Control and Transfusion groups over time. Significant increase in performance (15 +/- 8%) and VO2max (17 +/- 10%) (mean +/- SD) could be measured 48 h after RBC re-infusion, and remained increased for up to four weeks in some subjects. In total, 533 blood samples were included in the study (Clean = 220, Transfused = 313). In response to blood transfusion, the largest change in hematological variables occurred 48 h after blood donation, when Control and Transfused groups could be separated with OPLS-DA (R-2 = 0.76/Q(2) = 0.59). RBC re-infusion resulted in the bestmodel (R-2 = 0.40/Q(2) = 0.10) at the first sampling point (48 h), predicting one false positive and one false negative. Over all, a 25% and 86% false positives ratio was achieved in two separate trials. In conclusions, autologous re-infusion of RBCs increased VO2max and performance as hypothesized, but hematological profiling by multivariate statistics could not reach the WADA stipulated false positive ratio of <0.001% at any time point investigated. A majority of samples remained within limits of normal individual variation at all times.

National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-123974 (URN)10.1371/journal.pone.0156157 (DOI)000377564000009 ()27284981 (PubMedID)
Available from: 2016-07-07 Created: 2016-07-07 Last updated: 2018-06-07Bibliographically approved
Lindberg, A.-S., Wiklund, K., Andersson, M. & Malm, C. B. (2016). Firefighters' fit for duty score-model: Book of Abstracts. In: 21st Annual Congress of the European College of Sport Science: Crossing borders through sport science: . Paper presented at ECSS 2016 - 21st Annual Congress of the European College of Sport Science: Crossing borders through sport science, Vienna, Austria, Juli 6-9, 2016. ECSS, Article ID 2322.
Open this publication in new window or tab >>Firefighters' fit for duty score-model: Book of Abstracts
2016 (English)In: 21st Annual Congress of the European College of Sport Science: Crossing borders through sport science, ECSS , 2016, article id 2322Conference paper, Published paper (Other academic)
Abstract [en]

Physical capacity has previously been deemed important for firefighters’ physical work capacity, and evaluation of fitness for duty is common in the pre-hiring process. Various methods have been used to establish cut-off limits, i.e. normative data or expert judges. In accordance with government regulation, both full-time and part-time firefighters in Sweden have to pass a medical examination and a test of physical work capacity for permission to execute smoke diving. The physical work capacity test is a pass or fail test: dressed in firefighting protective clothes and breathing apparatus (total weight 24 ± 0.5 kg), six minutes walking with the incline at 8 degrees and treadmill speed of 4.5 km/h is performed. Inclusion of additional physical tests and appropriate cut-off limits is a decision taken by each individual municipality. The aim of the present study was to create a score model for evaluation of fitness for duty in the pre-hiring process of firefighters. Methods A total of 128 (64 men and 64 women) subjects: full-time firefighters, part-time firefighters and civilians, were included. Subjects performed five simulated firefighting work tasks and a selected battery six of physical tests including; 500 m rowing, grip strength, endurance bench press, track running 3000 m, standing broadjump and upright barbell row. The combined information from subjective evaluated cut-off limits, breakpoint estimation, checkpoint estimation and percentiles were used to create a score-model MO-PM30 Performance: Mixed Session 424 21ST ANNUAL CONGRESS OF THE EUROPEAN COLLEGE OF SPORT SCIENCE for evaluation of fit for duty. Results The models yielded various cut-off limits on the same physical test, depending on the work task investigated, but all tests were scored on a 1-11 scale. Consequently, the maximum total score was 66 and the minimum total score was 6. The recommended minimum total score of six tests is 36. Discussion In this study we created a score-model for evaluation of firefighters’ fit for duty in the pre-hiring process. When pre-hiring physical tests are performed, an easily conducted battery of physical tests is important in order to reduce costs but still maintain high validity and reliability. The score-model is easy to understand, performance gives the same score irrespectively of age and sex and makes it possible for the aspirants to prepare for the included physical tests. Since a specific physical test differs in importance in the prediction of simulated work task performance, the lack of performance in one physical test may not be fully compensated with a higher performance in another physical test. Simplifying and generalizing a method makes it practically usable at the detriment of accuracy on an individual level.

Place, publisher, year, edition, pages
ECSS, 2016
National Category
Sport and Fitness Sciences Other Physics Topics
Identifiers
urn:nbn:se:umu:diva-127283 (URN)
Conference
ECSS 2016 - 21st Annual Congress of the European College of Sport Science: Crossing borders through sport science, Vienna, Austria, Juli 6-9, 2016
Available from: 2016-11-04 Created: 2016-11-04 Last updated: 2019-06-14Bibliographically approved
Carlsson, M., Carlsson, T., Wedholm, L., Nilsson, M., Malm, C. & Tonkonogi, M. (2016). Physiological demands of competitive sprint and distance performance in elite female cross-country skiing. Journal of Strength and Conditioning Research, 30(8), 2138-2144
Open this publication in new window or tab >>Physiological demands of competitive sprint and distance performance in elite female cross-country skiing
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2016 (English)In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 30, no 8, p. 2138-2144Article in journal (Refereed) Published
Abstract [en]

The purpose was to investigate the relationship between elite females' competitive performance capability in sprint and distance cross-country skiing and the variables of gross efficiency (GE), work rate at the onset of blood-lactate accumulation (OBLA4mmol), maximal oxygen uptake (V[Combining Dot Above]O2max), maximal speed (Vmax), and peak upper-body oxygen uptake (V[Combining Dot Above]O2peak). Ten elite female cross-country skiers (age 24.5 ± 2.8 years) completed treadmill roller-skiing tests to determine GE, OBLA4mmol, and V[Combining Dot Above]O2max using the diagonal-stride technique as well as Vmax and V[Combining Dot Above]O2peak using the double-poling technique. International Ski Federations ranking points for sprint (FISsprint) and distance (FISdist) races were used as competitive performance data. There were correlations between the FISsprint and the V[Combining Dot Above]O2max expressed absolutely (p = 0.0040), Vmax (p = 0.012), and V[Combining Dot Above]O2peak expressed absolutely (p < 0.001) and as a simple ratio-standard (p = 0.049). The FISdist were correlated with OBLA4mmol (p = 0.048), V[Combining Dot Above]O2max expressed absolutely (L·min) (p = 0.015) and as a simple ratio-standard (p = 0.046), and V[Combining Dot Above]O2peak expressed absolutely (p = 0.036) and as a simple ratio-standard (ml·min·kg) (p = 0.040). The results demonstrate that the physiological abilities reflected by V[Combining Dot Above]O2max and V[Combining Dot Above]O2peak are indicators of competitive sprint and distance performance in elite female cross-country skiing. In addition, the ability to generate a high Vmax indicates the performance in sprint races, whereas the skier's OBLA4mmol reflects the performance capability in distance races. Based on the results, when evaluating the performance capacity of elite female cross-country skiers, it is recommended to use physiological variables that reflect competitive performance.

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2016
Keywords
lactate threshold, (V) over doto(2)max, double poling, maximal speed, women
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-102885 (URN)10.1519/JSC.0000000000001327 (DOI)000380752800009 ()26808846 (PubMedID)
Note

Originally included in thesis in submitted form.

Available from: 2015-05-08 Created: 2015-05-08 Last updated: 2018-06-07Bibliographically approved
Larsson, H., Tegern, M., Monnier, A., Skoglund, J., Helander, C., Persson, E., . . . Aasa, U. (2015). Content Validity Index and Intra- and Inter-Rater Reliability of a New Muscle Strength/Endurance Test Battery for Swedish Soldiers. PLoS ONE, 10(7), Article ID e0132185.
Open this publication in new window or tab >>Content Validity Index and Intra- and Inter-Rater Reliability of a New Muscle Strength/Endurance Test Battery for Swedish Soldiers
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2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 7, article id e0132185Article in journal (Refereed) Published
Abstract [en]

The objective of this study was to examine the content validity of commonly used muscle performance tests in military personnel and to investigate the reliability of a proposed test battery. For the content validity investigation, thirty selected tests were those described in the literature and/or commonly used in the Nordic and North Atlantic Treaty Organization (NATO) countries. Nine selected experts rated, on a four-point Likert scale, the relevance of these tests in relation to five different work tasks: lifting, carrying equipment on the body or in the hands, climbing, and digging. Thereafter, a content validity index (CVI) was calculated for each work task. The result showed excellent CVI (>= 0.78) for sixteen tests, which comprised of one or more of the military work tasks. Three of the tests; the functional lower-limb loading test (the Ranger test), dead-lift with kettlebells, and back extension, showed excellent content validity for four of the work tasks. For the development of a new muscle strength/endurance test battery, these three tests were further supplemented with two other tests, namely, the chins and side-bridge test. The inter-rater reliability was high (intraclass correlation coefficient, ICC2,1 0.99) for all five tests. The intra-rater reliability was good to high (ICC3,1 0.82-0.96) with an acceptable standard error of mean (SEM), except for the side-bridge test (SEM%>15). Thus, the final suggested test battery for a valid and reliable evaluation of soldiers' muscle performance comprised the following four tests; the Ranger test, dead-lift with kettlebells, chins, and back extension test. The criterion-related validity of the test battery should be further evaluated for soldiers exposed to varying physical workload.

Place, publisher, year, edition, pages
Public library science, 2015
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-107299 (URN)10.1371/journal.pone.0132185 (DOI)000358197600087 ()26177030 (PubMedID)
Available from: 2015-08-24 Created: 2015-08-21 Last updated: 2018-06-07Bibliographically approved
Lindberg, A.-S., Oksa, J., Antti, H. & Malm, C. (2015). Multivariate Statistical Assessment of Predictors of Firefighters' Muscular and Aerobic Work Capacity. PLoS ONE, 10(3), Article ID e0118945.
Open this publication in new window or tab >>Multivariate Statistical Assessment of Predictors of Firefighters' Muscular and Aerobic Work Capacity
2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 3, article id e0118945Article in journal (Refereed) Published
Abstract [en]

Physical capacity has previously been deemed important for firefighters physical work capacity, and aerobic fitness, muscular strength, and muscular endurance are the most frequently investigated parameters of importance. Traditionally, bivariate and multivariate linear regression statistics have been used to study relationships between physical capacities and work capacities among firefighters. An alternative way to handle datasets consisting of numerous correlated variables is to use multivariate projection analyses, such as Orthogonal Projection to Latent Structures. The first aim of the present study was to evaluate the prediction and predictive power of field and laboratory tests, respectively, on firefighters' physical work capacity on selected work tasks. Also, to study if valid predictions could be achieved without anthropometric data. The second aim was to externally validate selected models. The third aim was to validate selected models on firefighters' and on civilians'. A total of 38 (26 men and 12 women) + 90 (38 men and 52 women) subjects were included in the models and the external validation, respectively. The best prediction (R-2) and predictive power (Q(2)) of Stairs, Pulling, Demolition, Terrain, and Rescue work capacities included field tests (R-2 = 0.73 to 0.84, Q(2) = 0.68 to 0.82). The best external validation was for Stairs work capacity (R-2 = 0.80) and worst for Demolition work capacity (R-2 = 0.40). In conclusion, field and laboratory tests could equally well predict physical work capacities for fire-fighting work tasks, and models excluding anthropometric data were valid. The predictive power was satisfactory for all included work tasks except Demolition.

National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-102366 (URN)10.1371/journal.pone.0118945 (DOI)000351183500054 ()25775243 (PubMedID)
Available from: 2015-05-28 Created: 2015-04-23 Last updated: 2018-06-07Bibliographically approved
Carlsson, T., Carlsson, M., Hammarström, D., Rønnestad, B. R., Malm, C. B. & Tonkonogi, M. (2015). Optimal Formula V̇O 2max -to-mass ratio for performance among elite male cross-country skiers. Open Access Journal of Sports Medicine, 6, 353-360
Open this publication in new window or tab >>Optimal Formula V̇O 2max -to-mass ratio for performance among elite male cross-country skiers
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2015 (English)In: Open Access Journal of Sports Medicine, ISSN 1179-1543, E-ISSN 1179-1543, Vol. 6, p. 353-360Article in journal (Refereed) Published
Abstract [en]

The aim of this study was 1) to validate the 0.5 body-mass exponent for maximal. oxygen uptake [Formula: see text] as the optimal predictor of performance in a 15 km classical-technique skiing competition among elite male cross-country skiers and 2) to evaluate the influence of distance covered on the body-mass exponent for [Formula: see text] among elite male skiers. Twenty-four elite male skiers (age: 21.4±3.3 years [mean ± standard deviation]) completed an incremental treadmill roller-skiing test to determine their [Formula: see text]. Performance data were collected from a 15 km classical-technique cross-country skiing competition performed on a 5 km course. Power-function modeling (ie, an allometric scaling approach) was used to establish the optimal body-mass exponent for [Formula: see text] to predict the skiing performance. The optimal power-function models were found to be [Formula: see text] and [Formula: see text], which explained 69% and 81% of the variance in skiing speed, respectively. All the variables contributed to the models. Based on the validation results, it may be recommended that [Formula: see text] divided by the square root of body mass (mL · min(-1) · kg(-0.5)) should be used when elite male skiers' performance capability in 15 km classical-technique races is evaluated. Moreover, the body-mass exponent for [Formula: see text] was demonstrated to be influenced by the distance covered, indicating that heavier skiers have a more pronounced positive pacing profile (ie, race speed gradually decreasing throughout the race) compared to that of lighter skiers.

Keywords
allometric scaling, cross-country skiing, maximal oxygen uptake, pacing
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-146868 (URN)10.2147/OAJSM.S93174 (DOI)26719730 (PubMedID)
Available from: 2018-04-20 Created: 2018-04-20 Last updated: 2018-10-10Bibliographically approved
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