Summary and Discussion
The question of Graf KEYSERLINGK “what is the mechanism for the increased stiffness of the series elastic component in hypoxia” cannot yet be answered. The effect of hypoxia on the contractile function appears within about 5 minutes (BERNE, STEPHENS). There is a rapid fall over the next 30 minutes and then a slow fall for the following 30 minutes. Is the mechanical response seen by STEPHENS on electrical stimulation the result of direct excitation of muscle (VANHOUTTE)?