Muscle- and movement-specific fascicle-tendon interaction affects the performance of the neuromuscular system. This interaction is unknown among elderly and consequently contributes to the lack of understanding the age-related problems on neuromuscular control. The present experiment studied the age-specificity of fascicle-tendon interaction of the gastrocnemius medialis (GM) muscle in drop jump (DJ) exercises. Twelve YOUNG and thirteen ELDERLY subjects performed maximal squat jumps and DJs with maximal rebound effort on a sledge apparatus. Ankle and knee joint angles, reaction force and electromyography (EMG) from the soleus (SOL), GM and tibialis anterior (TA) muscles were measured together with the GM fascicle length by ultrasonography. The results showed that the measured ankle joint stiffness (AJS) during the braking phase correlated positively with the rebound speed in both age groups and that both parameters were significantly lower in ELDERLY than in YOUNG. In both groups the AJS correlated positively with averaged EMG (aEMG) in SOL during the braking phase and was further associated with GM activation (r=0.55, p<0.01) and TA coactivation (TA/GM r=-0.4 p<0.05) in ELDERLY. In addition, as compared to YOUNG, ELDERLY showed significantly lower GM aEMG in the braking phase and higher aEMG in the push-off phase, indicating less utilization of tendinous tissue (TT) elasticity. These different activation patterns are in line with the mechanical behaviour of GM showing significantly less fascicle shortening and relative TT stretching in the braking phase in ELDERLY than in YOUNG. These results suggest that age-specific muscle activation patterns as well as mechanical behaviours exist during DJs.