EFFECTS OF ECCENTRIC TRAINING ON THE MECHANICAL AND GEOMETRICAL PROPERTIES OF THE MUSCLE-TENDON PLANTAR FLEXORS SYSTEM

Aim: Determine the adjustments to the structures of the musculo-tendinous system of the Plantar flexors of the ankle 10 weeks of eccentric training, as well as the geometry of the triceps surae and muscles of the tendon of Achilles and the mechanical properties of the elastic components of the rheological model of Zajac (1989). Methods and equipment: Sixty two topics were randomly distributed in a training group (GE, n = 31, 5 beginnings, 6 boxers, 5 wrestlers, 7 jumpers in lengths and 8 basketball: 20.9 ± 2.6 years, 178.1 ± 8.3 cm, 68.4 ± 9.2 kg) and a group control (GC, n = 31, students of the Military Academy of sports: 23.6 ± 1.8 years, 176.6 ± 11.4 cm 72.0 ± 7.7 kg). All subjects were involved in regular sporting activity (10.5 ± 6.2 hours per week) and have not changed their usual activity during the duration of the study. The 3 experimental sessions were carried out in random order one to two weeks before the start of the training Protocol (pre-test) then a week after the end of the 10 weeks of training (post-test). Parameters studied: Characterization of the geometry of the muscles of the triceps surae, tendon of Achilles and the stiffness of these and properties mechanical tendon and the stiffness of the PRC. Results: The results showed that the mechanical properties of the tendon and muscle adapt specific and different way depending on the type of training to optimize the transmission process of skeletal muscle tension and storage-restitution of the elastic potential energy during movement. Conclusion: The 10 weeks of eccentric training did not alter performance vertical relaxation, flexibility, and strength of the trained subjects. Despite this lack of evolution of functional parameters, eccentric training would induce rather at the level of the intrinsic mechanical properties of muscle tissue (decrease in stiffness of these1) on the mechanical and geometrical properties of the tendon. The nature of the adaptations of the mechanical properties of the muscle and the tendon is associated with a change in intrinsic mechanical properties of muscle and tendon tissue rather than a change to the level of the geometric parameters of the muscle and the tendon. Keywords: Eccentric training, flexibility, elastic component, musculo-articular stiffness, muscle architecture, dissipated energy