Influence of knee flexion angle and age on triceps surae muscle fatigue during heel raises

The triceps surae (TS)muscle-tendon unit is 1 of the most commonly injured in eliteand recreational athletes, with a high prevalence in middle-agedadults. The performance of maximal numbers of unilateral heelraises is used to assess, train, and rehabilitate TS enduranceand conventionally prescribed in 0° knee flexion (KF) for thegastrocnemius and 45° for the soleus (SOL). However, theextent of muscle selectivity conferred through the change inthe knee angle is lacking for heel raises performed to volitionalfatigue. This study investigated the influence of knee angle onTS muscle fatigue during heel raises and determined whetherfatigue differed between middle-aged and younger-aged adults.