The effects of static stretching on the muscle- tendon properties are not yet well understood. Furthermore, there are limited studies which are addressed to the time course of stretching. To make a step forward in this topic, we conducted a study about the time course of the function responses (range of motion, passive resistive torque, maximum voluntary contraction) and the structural muscle-tendon properties (muscle- tendon stiffness, muscle stiffness, tendon stiffness) following a 3-minute static stretching exercise on the plantar flexor muscles for the first five minutes. We recruited 14 healthy volunteers (11 male, 3 female). They were tested on two separate days in a random order with two different rest times, namely 0 and 5 minutes. The “3 x 60 seconds” stretching intervention was passively executed by a dynamometer. To do all measurements, a dynamometer, an ultrasonography, a motion capture system (VICON) and an electromyography system has been used.The results show a significant increase in range of motion and a decrease of the passive resistive torque but does not influence the maximum voluntary force. The muscle- tendon stiffness decreased and the muscle stiffness too. There were no changes observed in the passive or active tendon stiffness. All results are significant at both points of time (immediately and 5 minutes after stretching). A 3 minutes static stretching exercise influences the functional and structural parameters of the muscle tendon unit. Concerning the structural parameters, there have been changes in muscle- but not in tendon structure. To a large extent, the results from this research study are confirm with our hypothesis and the results in actual relevant papers concerning this topic.