Fig. 1. Each training day of the intervention protocol consisted of five sets of repetitive (3 s loading, 3 s relaxation) isometric plantar flexion contractions to induce cyclic strain on the triceps surae tendon and aponeurosis. One leg exercised at low-magnitude tendon–aponeurosis strain [55% of the maximum voluntary contraction (MVC)] whereas the other one exercised at high-magnitude tendon–aponeurosis (90% MVC). The total exercise volume (integral of the plantar flexion moment over time) was identical for both legs. Signal: signal displayed on a computer monitor (3 s loading, 3 s relaxation) for controlling the exercise loading. Moment: plantar flexion moment generated during an exercise set.