ELASTIC RECOIL ACTIONS ARE SENSITIVE TO PRELOAD CONDITIONS
Ishikawa, M., Niemela, E., & Komi, P. V. (2005). Fascicle and tendinous tissue behavior in stretch-shortening cycle exercise performed with varying prestretch intensities. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 1434.
The interactions between fascicle and tendinous tissues in short contact drop jumps from three different heights were investigated.
With increasing drop heights, the braking force and flight time increased up to the optimal height. At greater heights, braking force continued to increase but flight time and lengthening of the fascicle and tendinous tissues decreased. The efficacy of elastic recoil in these structures decreased with increasing drop intensity beyond the preload that could be accommodated in a positive manner. The reactions of the vastus lateralis and medial gastrocnemius muscles changed differently throughout the range of exercises used, demonstrating the specificity of neuromuscular patterning in "like" movements of different intensity.
Implication. The elastic recoil of muscles ("effective catapult action") can be limited by the intensity of preparatory actions. Consequently, in actions involving recoil dominated movements (e.g., pitching, throwing), exaggeration of the preparatory movements could slow rather than improve the action's performance. Extreme care should be taken when altering the preloading conditions of explosive two-phase motor unit actions.
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