Abstract
It remains unclear whether neuromuscular electrical stimulation can induce sufficient
tendon stress to lead to tendon adaptations. Thus, we investigated the effect of such
a training program on the triceps surae muscle following the morphological and mechanical
properties of the Achilles tendon. Eight men participated in a 12-week high-frequency
neuromuscular electrical stimulation training program of the triceps surae muscle
under isometric conditions. Ultrasonography was used pre- and post-intervention to
quantify cross-sectional area, free length, and total length of the Achilles tendon,
as well as the myotendinous junction elongation during a maximal isometric ramp contraction
under plantar flexion. Neuromuscular electrical stimulation training does not lead
to changes in Achilles tendon free and total length, cross-sectional area, or maximal
elongation capacity. However, a significant increase was evidenced in maximal tendon
force post-training (+25.2%). Hence, Young’s Modulus and maximal stress were significantly
greater after training (+12.4% and +23.4%, respectively). High-frequency neuromuscular
electrical stimulation training induces repeated stress sufficient to lead to adaptations
of mechanical properties of the Achilles tendon. Thus, this training technique may
be of particular interest as a new rehabilitation method in tendinopathy management
or to counteract the effect of hypo-activity.
Key words
neuromuscular electrical simulation - achilles tendon - triceps surae - training