The growth of the muscle tibialis anterior in the normal rabbit in relation to the tension-length ratio

Abstract

The rate of longitudinal growth of the belly and tendon of the muscle tibialis anterior has been obtained from direct measurements of rabbits of various ages. The growth rate of the belly is more rapid than the increase in the distance which the belly shortens in causing the full range of movement of the foot, and the latter can therefore be effected by relatively less shortening of the muscle in the adult as compared with the young rabbit. The shape of the tension-length curve in isometric tetanus of tibialis anterior is quite similar in newborn and adult rabbits. However, a relatively greater length of the curve is occupied over the full range of movement of the belly in the intact leg of the young rabbit as compared with the adult, and hence, the tension exerted by tibialis anterior in full dorsi-flexion is a smaller proportion of the maximum tension in the young than in the adult.