Training-induced changes in muscles and their mechanics
Edith Cowan University, Australia
Muscles show remarkable plasticity in response to both use and disuse. Whilst changes at both micro and macro levels can occur, the overall aim of this presentation is to examine key macro-level changes that may critically affect muscle function. Changes in muscle size and architecture are thought to play an important role in muscle force (and power) generation, so changes in them should affect muscle performance. Nonetheless, relationships between changes in size and architecture and changes in muscle function are not consistently observed, and numerous methodological issues and misinterpretations of both human and animal data have potentially led to incorrect conclusions in this research area. The first specific aim of this presentation, therefore, is to review our current knowledge of the role of muscle size and architecture, and point out currently unresolved issues and misinterpretations of data. Additionally, changes in both collagenous and non-collagenous connective tissues also change with muscle use and disuse, and increasing evidence indicates that these may play a key role in muscle function. In particular, intra- and inter-fibre force transmission may be affected, and the ratio of muscle to fascicle (fibre) length changes during dynamic contractions may also be altered. An ongoing research effort is required to further understand whether changes in connective tissue structures can be specifically targeted with exercise training interventions, and whether these impact muscle function. A second specific aim of this presentation, therefore, is to review current evidence in this regard with the purpose of stimulating ongoing work.