Mechanical and metabolic function of different fibre-types: coordination between muscles

The intrinsic link between slower and faster muscle contractile elements in the musculoskeletal system can be generalised across scales from motor units within a muscle to synergistic muscles. At both scales, a unified plan should govern recruitment during movement across a range of mechanical demands. In this study, we used musculoskeletal simulations and a cycling paradigm to predict the coordination between synergistic muscles as well as the recruitment of motor units within an individual muscle. We found that across scales, only the simulations that allowed for independently activated elements and a metabolically-informed cost function predicted measured recruitment strategies across varying mechanical demands and deployed the contractile elements in a metabolically and mechanically effective manner.