The authors previously studied the mechanics of the Rana pipiens semitendinosus (ST) muscle, assuming zero tendon compliance. The tendon of this muscle is relatively short, perhaps justifying the assumption. A study is reported here of the load-deformation and load-strain properties of these tendons. The tendon slack length was measured at 2.2 mu m. In this case, the muscle force was not altered. However, at different sarcomere lengths, tension might be affected. These results must be compared to physiological situations, i.e. the frog hop, in order to determine the true significance of the tendon compliance. >