Dynamic tensile properties of the plantaris tendon of sheep (Ovis aries).

1. The stresses applied during fast locomotion are sufficient to stretch the tendon far into the linear region of the load-extension plot. 2. The tangent modulus in the linear region is about 1.65 GN.m-2 and is independent of frequency for oscillations in the range 0.22 to 11 Hz. 3. Internal damping dissipates about 7% of the mechanical energy applied during oscillations. The load range (0 to about 1 kN) and frequencies (0.22 to 11 Hz) were comparable to those arising during locomotion. 4. The rate of rise of temperature, during the initial period of an oscillation, was consistent with the mechanical measurement of power loss. 5. The dynamic mechanical properties are appropriate for the hypothesis of energy saving by storage in tendons during fast locomotion.