[Application of the Doppler examination to the study of changes in the venous circulation of muscles during exercise]

The authors use Doppler examination to study the functional hyperaemia of healthy muscle during muscle contraction. In the leg, isometric contraction of the gastrocnemii produces: 1) a flush effect, rapid but transient (1 to 2 sec.); 2) next a speed intermediate between that at peak and that at rest; 3) finally, a post-contractile hyperaemia. In the case of isotonic contractions, the same type of tracing is oberved more clearly for dorsal flexion of the foot (dorsiflexion) than for plantar flexion (extesion), and this occurs whether the mode of movement is active or passive. In the normal untrained subject, fatigue due to repetition of movement occurs very quickly, whatever the conditions, and results in a diminution of the venous flush. But in the trained subject, this effect does not appear, or not till much later.