Aim: To evaluate the effect of long-term training on muscle architecture a comparison was made between preferred (Pf) and nonpreferred (NPf) leg fascicle lengths in athletes that have clear differences in amount of loading between legs and in control subjects. We hypothesised that these athletes would show greater differences in fascicle lengths between legs than the control subjects. Methods: 16 well-trained male and female athletes (high-jump and long-jump) and 9 control subjects were included. Muscle architecture (i.e. fascicle length, pennation angle, muscle thickness) data was collected for the Medial Gastrocnemius muscle in various conditions (i.e. 90° ankle angle, tendon-slack length (TSL) angle, during passive rotations and ankle joint plantar flexion MVC) using ultrasonography (B-mode; 30 Hz). In this abstract the results are restricted to fascicle length data at TSL angle. TSL angle was defined for each subject individually as the ankle joint angle at which the fascicles are at a length where tendon slack has been taken up and thus force from muscle fascicles is directly transferred to the segment. The intra-researcher reliability showed a low error (0.93 ± 0.36 mm). Subjects were asked about their preferred leg for jumping and a two-way ANOVA was used to test for main and interaction effects of the difference in Pf and NPf for the two groups, gender and track event. Significance level of p<0.05 was used. Results: 4 control subjects reported not to have a preferred jumping leg. Athletes had longer fascicle lengths (Lf = 57.63 ± 6.96 mm) than control subjects (Lf = 52.27 ± 5.30 mm) when both legs for each subject were used in the analysis. A difference was found between Pf and NPf for all subjects combined (n = 21; mean difference: 2.31 ± 3.87 mm; p = 0.013). No difference (p = 0.122) was found between athletes (mean difference: 2.80 ± 3.56 mm) and controls (mean difference: 0.76 ± 4.04 mm) in fascicle length difference between Pf and NPf. Visual inspection of the data showed that even the 4 control subjects with no preferred jumping leg showed large differences between both legs in fascicle lengths. Discussion: Although high- and long-jump athletes report to have a clearly preferred leg for jumping and loading during training is higher on the jumping leg, this does not result in greater fascicle length differences in that leg as compared to control subjects. This may indicate that fascicle length does not necessarily change more under this long-term training but that other parameters (for example pennation angle, tendon stiffness) might be more subjective to change. ABSTRACT FROM AUTHOR
© Copyright 2016 21st Annual Congress of the European College of Sport Science (ECSS), Vienna, 6. -9. July 2016. Veröffentlicht von University of Vienna. Alle Rechte vorbehalten.