Meeting Abstract
When muscle-tendon units (MTU) absorb energy via active lengthening, energy flows into an elastic tendon before being dissipated by the muscle. Energy flow into the tendon has been hypothesized to act as a mechanical buffer, thereby reducing peak muscle force, velocity, and power input to the muscle. To fully test these hypotheses, however, experiments that completely limit the flow of energy into the tendon must be conducted. We performed these experiments in silico by creating a muscle-tendon simulation using parameters from turkey gastrocnemius muscles. The model was validated with experimental data, and tendon stiffness was adjusted such that our model matched previous experimental results. We virtually stretched active muscle-tendon units at different rates and measured muscle force, velocity, and power over time. We then modified the model to prevent energy flow into the tendon and repeated the simulation experiments. By comparing these two datasets, we found that tendons have a large capacity to reduce peak muscle velocity and power input (in some cases, completely eliminating muscle lengthening during the period of force rise). Reductions in peak muscle force were possible but were sensitive to the duration of lengthening. These results indicate that the ability of turkey tendons to buffer muscle force, velocity, and power are dependent on the interaction of lengthening and muscle dynamics.
