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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Online ISSN 1827-1928
Lévénez M. 1, Theunissen S. 1, 2, Bottero A. 1, 2, Snoeck T. 1, 3, Bruyère A. 1, 2, Tinlot A. 1, Balestra C. 2, 3, Provyn S. 1, 3, 4
1 Anatomy, Morphology and Biomechanics Department Haute Ecole Paul Henri Spaak, Brussels, Belgium;
2 Environmental and Occupational Physiology Department Haute Ecole Paul Henri Spaak Brussels, Belgium;
3 Experimental Anatomy Department Vrije Universiteit Brussel, Brussels, Belgium;
4 Human Anatomy Department Vrije Universiteit Brussel, Brussels, Belgium
Aim: Our study’s aim is to show how a five-week stretch training protocol, based on passive stretching, can change muscle performance during a drop jump (stretch shortening cycle).
Methods: This study observes in 8 healthy subjects (four males and four females), the effect of a 5-week passive stretch training protocol on the stretch shortening cycle (SSC) during the performance of a drop jump, and identify the architectural changes in the muscle.
Subjects underwent measurements of their drop jump performance 3 times before, and 3 times after, the stretch training protocol. For the muscle tendon unit (MTU), changes were measured using the Hawkins and Hull’s model. In order to calculate the length changes in the MTU, we measured the ankle and knee angles. For changes in the fascicle, the pennation angle and the thickness of the gastrocnemius medialis (GM) muscle were measured.
Results: After the 5-week stretch training protocol, a significant increase in flexibility was observed in the fascicle during the first phase of the jump (a shortening of 10% after training vs. 20% before). No significant change was observed in the tendon, while the MTU showed a highly significant improvement (P<0.01) in muscle compliance during the landing phase. The average performance during the drop jump also showed a highly significant change (P<0.01).
Conclusion: The results show a higher degree of flexibility in the MTU, enabled the latter to store more energy which was then converted to kinetic energy during the push-off phase of the drop jump.