Plantar-flexor static stretch training effect on eccentric and concentric peak torque – a comparative study of trained versus untrained subjects

Abstract

AbstractThe aim of this study was to examine the long-term effects of static stretching of the plantar-flexor muscles oneccentric and concentric torque and ankle dorsiflexion range of motion in healthy subjects. Seventy five healthy malevolunteers, with no previous history of trauma to the calf that required surgery, absence of knee flexion contracture andno history of neurologic dysfunction or disease, systemic disease affecting the lower extremities were selected for thisstudy. The participants were divided into three equal groups. The control group did not stretch the plantar-flexormuscles. Two Experimental groups (trained and untrained) were instructed to perform static stretching exercise of 30second duration and 5 repetitions twice daily. The stretching sessions were carried out 5 days a week for 6 weeks. Thedorsiflexion range of motion was measured in all subjects. Also measured was the eccentric and concentric torque ofplantar-flexors at angular velocities of 30 and 120o/s pre and post stretching. Analysis of variance showed a significantincrease in plantar-flexor eccentric and concentric torque (p < 0.05) of trained and untrained groups, and an increase indorsiflexion range of motion (p < 0.05) at both angular velocities for the untrained group only. The static stretchingprogram of plantar-flexors was effective in increasing the concentric and eccentric plantarflexion torque at angularvelocities of 30 and 120o/s. Increases in plantar-flexors flexibility were observed in untrained subjects.