Article

OBJECTIVE: To present the properties of an eccentric contraction and compare
neuromuscular and muscle-tendon system adaptations induced by isotonic and
isokinetic eccentric trainings. SYNTHESIS: An eccentric muscle contraction is
characterized by the production of muscle force associated to a lengthening of
the muscle-tendon system.
This muscle solicitation can cause micro lesions
followed by a regeneration process of the muscle-tendon system. Eccentric
exercise is commonly used in functional rehabilitation for its positive effect on
collagen synthesis but also for resistance training to increase muscle strength
and muscle mass in athletes. Indeed, eccentric training stimulates muscle
hypertrophy, increases the fascicle pennation angle, fascicles length and neural
activation, thus inducing greater strength gains than concentric or isometric
training programs. Eccentric exercise is commonly performed either against a
constant external load (isotonic) or at constant velocity (isokinetic), inducing
different mechanical constraints. These different mechanical constraints could
induce structural and neural adaptive strategies specific to each type of
exercise. CONCLUSION:
The literature tends to show that isotonic mode leads to a
greater strength gain than isokinetic mode. This observation could be explained
by a greater neuromuscular activation after IT training. However, the specific
muscle adaptations induced by each mode remain difficult to determine due to the
lack of standardized, comparative studies.
CI - 2010 Elsevier Masson SAS. All rights reserved.

Langue : ANGLAIS ; FRANCAIS