Fig. 5. Comparison of the strain (A) and shortening velocity (B) for the simulation and sawtooth cycles and the stress (C) and instantaneous power output (D) developed. The stress was higher during the simulation (in vivo length cycle) cycle than during the sawtooth cycle throughout most of shortening; however, the instantaneous power output was only greater during the later part of shortening. L is muscle length, and saw 70% cycle refers to a sawtooth length cycle in which 70% of the total cycle duration is spent shortening.