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Publications (10 of 13) Show all publications
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
Theos, A., Gortsila, E. & Maridaki, M. (2017). Effects of Training Surface on Physiological Characteristics of Prepubescent Female Volleyball Players. International Journal of Pediatric Health Care & Advancements, 4(5), 48-53
Open this publication in new window or tab >>Effects of Training Surface on Physiological Characteristics of Prepubescent Female Volleyball Players
2017 (English)In: International Journal of Pediatric Health Care & Advancements, ISSN 2572-7354, Vol. 4, no 5, p. 48-53Article in journal (Refereed) Published
Abstract [en]

Purpose: The present study investigated the effects of different training surfaces on physiological characteristics of prepubescent female volleyball players.

Method: 45 prepubescent girls (age: 11.1 ± 0.5 years) were separated in groups S (N=15) and H (N=15) that consisted of volleyball players, while group C (N=15) consisted of girls that had no volleyball training experience. Groups S and H participated in a 10-week volleyball training program including sprints, jumps and technical exercises, while group C executed only technical skills exercises. Group S trained on sand surface, while groups H and C trained on hard surface indoors. Aerobic capacity (20m shuttle run), agility (Illinois test), countermovement (CMJ) and squat jump (SJ) as well as 10m sprint test were conducted before, in the middle (5th week) and after the end of the training program for groups S and H. Group C was tested only before and after the training period.

Results: Aerobic capacity, agility, jumping and sprinting ability were significantly (p<0.01) improved in groups S and H even from the 5th week of training. Group S achieved greater improvements than group H in all tested variables.

Conclusion: Training on sand surface seems to promote training adaptations improving the physiological characteristics of prepubescent female volleyball players.

Place, publisher, year, edition, pages
Delaware, USA: SciDoc Publishers, 2017
Keywords
Children, Team Sport, Aerobic Capacity, Jumping Ability
National Category
Sport and Fitness Sciences
Research subject
literature for children and adolescents
Identifiers
urn:nbn:se:umu:diva-145550 (URN)10.19070/2572-7354-1700014 (DOI)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09Bibliographically approved
Giannopoulos, A., Yeung, C.-Y. C. & Theos, A. (2017). Quantification of Cell Generated Forces: A Tool to Assess Functionality. Journal of Orthopedic Research and Therapy (8), Article ID JORT-168.
Open this publication in new window or tab >>Quantification of Cell Generated Forces: A Tool to Assess Functionality
2017 (English)In: Journal of Orthopedic Research and Therapy, ISSN 2575-8241, no 8, article id JORT-168Article in journal, Editorial material (Refereed) Published
Keywords
tissue development, cell-matrix interactions
National Category
Sport and Fitness Sciences
Research subject
cell research
Identifiers
urn:nbn:se:umu:diva-145548 (URN)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09Bibliographically approved
Krooks, D., Johansson, M. & Theos, A. (2016). Cancer cachexia and the effects of physical activity. Gavin Journal of Orthopedic Research and Therapy (3), Article ID J125.
Open this publication in new window or tab >>Cancer cachexia and the effects of physical activity
2016 (English)In: Gavin Journal of Orthopedic Research and Therapy, ISSN 2575-8241, no 3, article id J125Article in journal (Refereed) Published
Abstract [en]

Physical activity is, among other things, characterized by an increased quality of life and several physiological positive results such as hypertrophy and counteracting atrophy. Cachexia has been proven to degradate muscle proteins and seems to be a death contributing factor during cancer.Cachectic muscles are resistant to anabolic effects, and this knowledge combined with the many proven positive outcomes on muscle hypertrophy by exercise led this study to investigate the previous studies conducted on this subject further. The Ubiquitin-Proteasome System (UPS) plays a significant role in protein degradation, more specifically the E3 ubiquitin ligases MuRF-1 (Muscle RING Finger protein-1) and MaFbx (Muscle atrophy F-box), which are FoxO (forkhead box-O) transcription factors. The UPS can be inhibited by substrates upregulated by physical activity, such as IGF-1 (Insulin-like Growth Factor-1) and PGC-1α (Peroxisome proliferator-activated receptor gamma coactivator 1-alpha). In conclusion, there are a lot of pathways in both cancer cachexia and physical activity that border on each other, but the molecular mechanisms are complex and not always clear.

Place, publisher, year, edition, pages
Lisle: Gavin Publishers, 2016
Keywords
muscle hypertrophy, muscle atrophy, protein degradation
National Category
Sport and Fitness Sciences
Research subject
Physiology
Identifiers
urn:nbn:se:umu:diva-139075 (URN)
Available from: 2017-09-06 Created: 2017-09-06 Last updated: 2018-06-09Bibliographically approved
diva2:1189417
Open this publication in new window or tab >>Effect of Training Surface on Agility and Passing Skills of Prepubescent Female Volleyball Players
2013 (English)In: Journal of Sports Medicine & Doping Studies, ISSN 2332-7839, E-ISSN 2161-0673, Vol. 3, article id 128Article in journal (Refereed) Published
Abstract [en]

The purpose of the present study was to investigate the effect of different training surfaces (hard or sand surface) on agility and passing skills of prepubescent female volleyball players. 45 prepubescent girls (age: 11.1 ± 0.5 years) participated in this study and were separated in three groups. Groups S (N=15) and I (N=15) consisted of volleyball players, while group C (N=15) consisted of girls that had no volleyball training experience. All groups participated in a 10-week (3 days/week) volleyball training program that included technical and passing skills exercises. The program of groups S and I also included jumping and sprinting exercises. The training program of group S was conducted on sand surface, while groups I and C trained on hard surface. Measurements of agility (T-test and 505-test) and passing skills were conducted on both hard and sand surface before, in the middle (5th week) and after the end of the training program for groups S and I. Group C was tested only on hard surface before and after the training period. Data were analyzed using two-way ANOVA for independent samples. Agility T-test and 505-test were significantly (p<0.001) improved in all three groups after the 10-week training program. Agility improvement of group S was significantly (p<0.001) greater than the other two groups (I and C), regardless of the surface (hard or sand) that the test was executed. Group S achieved greater improvements than the other two groups in passing skills too. All three groups were significantly (p<0.001) improved in overhead and forearm passing accuracy after the 10-week training period, but it was group S that achieved the greatest improvement, regardless of the (hard or sand) that the test was executed. In conclusion training on sand surface could be a useful and effective tool for improving agility and passing skills in prepubescent female volleyball players

Keywords
T-test, 505-test, Sand surface, Overhead pass, Forearm pass
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-145560 (URN)10.4172/2161-0673.1000128 (DOI)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09Bibliographically approved
Philippou, A., Maridaki, M., Theos, A. & Koutsilieris, M. (2012). Cytokines in muscle damage. Advances in Clinical Chemistry, 58, 49-87
Open this publication in new window or tab >>Cytokines in muscle damage
2012 (English)In: Advances in Clinical Chemistry, ISSN 0065-2423, E-ISSN 2162-9471, Vol. 58, p. 49-87Article in journal (Refereed) Published
Abstract [en]

Multiple cellular and molecular processes are rapidly activated following skeletal muscle damage to restore normal muscle structure and function. These processes typically involve an inflammatory response and potentially the consequent occurrence of secondary damage before their resolution and the completion of muscle repair or regeneration. The overall outcome of the inflammatory process is potentially divergent, with the induction of prolonged inflammation and further muscle damage, or its active termination and the promotion of muscle repair and regeneration. The final, detrimental, or beneficial effect of the inflammatory response on muscle repair is influenced by specific interactions between inflammatory and muscle cell-derived cytokines that act as positive and/or negative regulators to coordinate local and systemic inflammatory-related events and modulate muscle repair process. A crucial balance between proinflammatory and anti-inflammatory cytokines appears to attenuate an excessive inflammatory reaction, prevent the development of muscle fibrosis, and adequately promote the regenerative process. In this review, we address the interactive cytokine responses following muscle damage, in the context of induction and progression, or resolution of muscle inflammation and the promotion of muscle repair.

National Category
Sport and Fitness Sciences
Research subject
Physiology
Identifiers
urn:nbn:se:umu:diva-145556 (URN)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09
diva2:1189411
Open this publication in new window or tab >>Subdivision of molecularly-classified groups by new gene signatures in breast cancer patients
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2012 (English)In: Oncology Reports, ISSN 1021-335X, E-ISSN 1791-2431, Vol. 28, no 6, p. 2255-2263Article in journal (Refereed) Published
Abstract [en]

Gene expression patterns as well as gene interactions are under investigation for their involvement in tumour heterogeneity. The molecular classification of breast cancer based on hormone receptor expression, grade and HER2 receptor levels, is indicative but not adequate enough to complete the prognostic data. The objectives of this study were to validate the prognostic value of 19 genes, solely, and as parts of classifiers (sets of genes), in breast cancer patients and to determine whether the expression of these genes and classifiers is correlated with breast cancer molecular classification. Gene expression was examined in the blood of 88 breast cancer patients and 50 healthy controls using multiplex quantitative real-time PCR. Patients with a second primary malignancy showed a statistically significant difference when compared with: i) patients with a single breast cancer, for an 8-gene classifier (p<0.02); and ii) healthy individuals (classifier FBX033, FLJ339115) (p<0.01), with respect to gene expression. The classifier ENY2, USP38 was associated with the development of primary breast cancer. A newly established classifier (ENY2, USP38, RPS7, Osbpl-1 and ETF1) indicated a statistically significant association with HER2 subtype patients, compared to patients with a different molecular classification (p<0.04). The gene FLJ33915 was differentially expressed in a subgroup of HER2-positive patients with infiltrated axillary lymph nodes (p<0.028). We validated the prognostic value of 4 classifiers for primary and second primary malignancy. Evidence of a classifier predicting the HER2 subtype and the gene FLJ33915 which subdivides HER2 subtype patients is also presented.

National Category
Cancer and Oncology
Identifiers
urn:nbn:se:umu:diva-145558 (URN)10.3892/or.2012.2018 (DOI)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09
Bogdanis, G. C., Papaspyrou, A., Souglis, A., Theos, A., Sotiropoulos, A. & Maridaki, M. (2011). Effects of two different half-squat training programs on fatigue during repeated cycling sprints in soccer players. Journal of Strength and Conditioning Research, 5(7), 1849-1856
Open this publication in new window or tab >>Effects of two different half-squat training programs on fatigue during repeated cycling sprints in soccer players
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2011 (English)In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 5, no 7, p. 1849-1856Article in journal (Refereed) Published
Abstract [en]

This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal half-squat strength increased significantly in both groups (p < 0.01), but this increase was significantly greater in the S-group compared with the H-group (17.3 ± 1.9 vs. 11.0 ± 1.9%, p < 0.05). Lean leg volume (LLV) increased only in the H-group. Total work over the 10 sprints improved in both groups after training, but this increase was significantly greater in the second half (8.9 ± 2.6%) compared with the first half of the sprint test (3.2 ± 1.7%) only in the S-group. Mean power output (MPO) expressed per liter of LLV was better maintained during the last 6 sprints posttraining only in the S-group, whereas there was no change in MPO per LLV in the H-group over the 10 sprints. These results suggest that resistance training with high loads is superior to a moderate-load program, because it increases strength without a change in muscle mass and also results in a greater improvement in repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players.

Place, publisher, year, edition, pages
Wolters Kluwer, 2011
Keywords
hypertrophy, maximal strength, running economy, fatigue
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-145552 (URN)10.1519/JSC.0b013e3181e83a1e (DOI)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09
Philippou, A., Armakolas, A., Panteleakou, Z., Pissimissis, N., Nezos, A., Theos, A., . . . Koutsilieris, M. (2011). IGF1Ec Expression in MG-63 Human Osteoblast-like Osteosarcoma Cells. Anticancer Research, 31(12), 4259-4265
Open this publication in new window or tab >>IGF1Ec Expression in MG-63 Human Osteoblast-like Osteosarcoma Cells
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2011 (English)In: Anticancer Research, ISSN 0250-7005, E-ISSN 1791-7530, Vol. 31, no 12, p. 4259-4265Article in journal (Refereed) Published
Abstract [en]

AIM: The insulin-like growth factor 1 (IGF1) gene gives rise to multiple transcripts, using an elaborate alternative splicing mechanism. The aim of this study was to shed light on the expression and role of the IGF1 system in human MG-63 osteoblast-like osteosarcoma cells.

MATERIALS AND METHODS: The expression of the IGF1Ea, IGF1Eb and IGF1Ec isoforms was characterized using reverse transcription polymerase chain reaction (RT-PCR), quantitative real time-PCR (qRT-PCR) and western blot analysis. Using trypan blue exclusion assays, we also examined the mitogenic effects of IGF1 and of a synthetic peptide related to the E domain of IGF1Ec (synthetic E peptide) on MG-63 cells, as well as on MG-63 cells which had been molecularly modified to restrain the expression of type I IGF receptor (IGF1R) and of insulin receptor (INSR) by siRNA techniques (IGF1R KO or INSR KO MG-63 cells).

RESULTS: MG-63 cells express only the IGF1Ea and IGF1Ec transcripts. Exogenous administration of dihydrotestosterone (DHT) significantly increased the expression of IGF1Ea and IGF1Ec mRNA and it induced the previously undetectable expression of IGF1Eb transcript. Exogenous administration of IGF1, insulin and the synthetic E peptide stimulated the growth of MG-63 cells, while only E peptide stimulated the growth of IGF1R KO and INSR KO MG-63 cells.

CONCLUSION: These data suggest that the expression of all IGF1 isoforms is hormonally regulated in MG-63 cells and that the expression of IGF1Ec may be involved in osteosarcoma biology by generating the Ec peptide which acts via an IGF1R-independent and INSR-independent mechanism.

Keywords
Insulin-like growth factor 1, MG-63 osteosarcoma cells, alternative splicing
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:umu:diva-145555 (URN)000298514300029 ()22199289 (PubMedID)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09Bibliographically approved
Bogdanis, G. C., Papaspyrou, A., Souglis, A., Theos, A., Sotiropoulos, A. & Maridaki, M. (2008). Effects of a hypertrophy and a maximal training program on speed, force and power of soccer players. In: Tom Reilly and Feza Korkusuz (Ed.), Science and Football, VI: The Proceedings of the Sixth World Congress on Science and Football (pp. 290-295). Routledge
Open this publication in new window or tab >>Effects of a hypertrophy and a maximal training program on speed, force and power of soccer players
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2008 (English)In: Science and Football, VI: The Proceedings of the Sixth World Congress on Science and Football / [ed] Tom Reilly and Feza Korkusuz, Routledge, 2008, p. 290-295Chapter in book (Refereed)
Place, publisher, year, edition, pages
Routledge, 2008
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-145561 (URN)0415429099 (ISBN)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2018-06-09
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8191-6659

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