MUSCULAR FORCE IN RUNNING TURKEYS - THE ECONOMY OF MINIMIZING WORK

During running, muscles and tendons must absorb and release mechanical work to maintain the cyclic movements of the body and limbs, while al so providing enough force to support the weight of the body. Direct me asurements of force and fiber length in the lateral gastrocnemius musc le of running turkeys revealed that the stretch and recoil of tendon a nd muscle springs supply mechanical work while active muscle fibers pr oduce high forces. During level running, the active muscle shortens li ttle and performs little work but provides the force necessary to supp ort body weight economically. Running economy is improved by muscles t hat act as active struts rather than working machines.