Optimization of muscles and movement for performance or economy of energy

This paper shows by a series of examples how the muscles and movements of h umans and animals seem to he designed, in some cases to give maximum perfor mance and in others to minimize energy costs. The swimming muscles of fishe s seem to be designed so that, when maximum power output is required, they are shortening at the rates at which they can produce most power. Muscles t hat drive oscillatory movements will use least energy if they have the opti mum combination of muscle properties and tendon elasticity. High jumpers an d long jumpers must run up at different speeds, and set down their legs at different angles, to perform the best jumps. We adjust various features of our gait, as we change speed, to minimize the energy cost of travelling on foot.