Mattes, K, Wollesen, B, and Manzer, S. Asymmetries of maximum trunk, hand, and leg strength in comparison to volleyball and fitness athletes. J Strength Cond Res 32(1): 57-65, 2018-Playing volleyball and corresponding training loads lead to specific strains and might result in asymmetric muscle pattern. The study aimed to identify volleyball-specific maximum bilateral strength asymmetries in comparison to fitness athletes. The cross-sectional study design compared an age-matched male volleyball group (n = 23; 27.9 ± 5 years) with a fitness group (n = 30; 26.3 ± 3 years). The participants performed an isometric maximum handgrip strength test followed by 2 isokinetic concentric maximum strength tests to determine the performance capacity of the axial trunk rotators (left-right) and bilateral leg extensors. Differences between groups and left-right side (within group) were proven by variance analysis with repeated measurements. There was a left-right difference with higher maximum forces for the rotation in the right direction in the volleyball group (p = 0.0058) but the group interaction effect was not significant after alpha error accumulation. The results of the leg press indicated a stronger left leg in the fitness group (nonsignificant) in comparison to the volleyball group. Overall, the volleyball group displayed symmetry in maximum handgrip and leg strength and asymmetry in trunk rotation with higher strength in right rotation. This asymmetry for the right trunk rotation showed a small effect size. The resulting asymmetry might be an adaptation to the volleyball techniques, but it remains unclear if this is a cause for or of injury. As a practical implication, the asymmetries should be examined to develop individualized strength training programs for both groups.

No abstract

No abstract

Mattes, K., Schaffert, N., Manzer, S., & Böhmert, W. (2015). Cross-sectional analysis of rowing power and technique of german junior women in the eight. J. Hum. Sport Exerc., 10(2), pp.571-582. Since ten years, the German Rowing Federation (DRV) annually conducted 2000-m-race-tests with the best-performing athletes at the beginning of the immediate-pre-competition-preparation (IPCP) for the World-Rowing-JuniorChampionships (WRJC). According to previous findings, differences between year-groups, correlations between anthropometric-data, rowing-power and technique development were tested to identify trends and to define a performance-strategy. Twenty test-runs of the junior-women's-Eight (N=156) were studied using a mobile-measuring-system that records rowing-force and rowing-angle. Body height, body mass, average handle-power with its components handle-force, velocity and handle-displacement per stroke and further rowing-technical characteristics of the rowing-stroke-length were considered and WRJC-race-times used as external-criteria. Single-factor-variance-analysis, linear-correlation, regression-analysis and cluster-analysis were calculated. Significant differences were found between year-groups in body height, body mass and in characteristic values for rowing-power and technique and significant correlations between body height and body mass with rowing-power. Further, six performance-groups were identified by rowing-technique-data. Significant reduction was found in crew's WRJC-race-time, reflected in handle-power and its determinants. Cross-sectional-comparison showed significant increase in average handle-power and handle-force per rowing-stroke at higher stroke frequency. Based on the cross-sectional-data, selection and year-group influences, together with exercise-induced-effects, should be considered as causes. Results show a functioning preparation-system within the DRV for better prepared-junior-athletes to commence the IPCP.

No abstract