Is soleus muscle-tendon-unit behavior related to ground-force application during the sprint start?

Purpose: To describe the stretch-shortening behavior of ankle plantar-flexing muscle-tendon units (MTUs) during the push-off in a sprint start. Methods: Fifty-four male (100-m personal best: 9.58-12.07 s) and 34 female (100-m personal best: 11.05-14.00 s) sprinters were analyzed using an instrumented starting block and 2-dimensional high-speed video imaging. Analysis was performed separately for front and rear legs, while accounting for block obliquities and performance levels. Results: The results showed clear signs of a dorsiflexion in the upper ankle joint (front block 15.8° ± 7.4°, 95% CI 13.2-18.2°; rear block 8.0° ± 5.7°, 95% CI 6.4-9.7°) preceding plantar flexion. When observed in their natural block settings, the athletes` block obliquity did not significantly affect push-off characteristics. It seems that the stretch-shortening-cycle-like motion of the soleus MTU has an enhancing influence on push-off force generation. Conclusion: This study provides the first systematic observation of ankle-joint stretch-shortening behavior for sprinters of a wide range of performance levels. The findings highlight the importance of reactive-type training for the improvement of starting performance. Nonetheless, future studies need to resolve the independent contributions of tendinous and muscle-fascicle structures to overall MTU performance.
© Copyright 2017 International Journal of Sports Physiology and Performance. All rights reserved.

Bibliographic Details
Subjects:
Notations:strength and speed sports
Tagging:Streckungs-Verkürzungs-Zyklus
Published in:International Journal of Sports Physiology and Performance
Language:English
Published: 2017
Online Access:https://doi.org/10.1123/ijspp.2015-0512
Volume:12
Issue:4
Pages:448-454
Document types:article
Level:advanced