We hypothesize that the neuromuscular system is designed to function effectively in accomplishing everyday movement tasks. Since everyday movement tasks may vary substantially in terms of speed and resistance, we speculate that agonistic muscles contribute differently to varying movement tasks such that the mechanical, structural, and physiological properties of the system are optimized at all times. We further hypothesize that a mechanical perturbation to the musculoskeletal system, such as the loss of an important joint ligament or the change of a muscle’s line of action, causes an adaptation of the system aimed at reestablishing effective function. Here. we demonstrate how the specificity of the cat ankle extensors is used to accommodate different locomotor tasks. We then illustrate how the loss of an important ligament in the cat knee leads to neuromuscular adaptation. Finally, we discuss the adaptability of skeletal muscle following an intervention that changes a muscle’s line of action, moment arm, and excursion.
Walter Herzog, Timothy Koh, Evelyne Hasler and Tim Leonard
Robin Healy, Ian C. Kenny and Andrew J. Harrison
about the SSC should not be made from 1 specific muscle and from 1 condition only. 4 Direct methods using in vivo force measurements have been employed to characterize SSC function in isolated muscles during human locomotion. Based on these methods, 3 fundamental conditions have been identified for