[Changes in blood flow after longitudinal stretching of the cat m. gastrocnemius]

Longitudinal stretch of the cat m. gastrocnemius by 10-30% of initial length increased the passive strength and regularly decreased the blood flow, the latter being dependent not on the degree of deformation but on the value of passive tension. Postelongation hyperemia develops after the stretch. This reaction seems to be similar to hyperemia due to the artery occlusion in the muscle and is considerably weaker than the postcontraction increase in the blood flow. The character of intramuscular mechanical effects on the vessels during both the active contractions and the passive stretch, is discussed.