This introduction includes a brief description of 4 papers that were prepared after the symposium The stress response in muscle: mechanisms and functional implications, which was presented at the Canadian Society for Exercise Physiology (CSEP) annual meeting in the autumn of 2006. These papers discuss the role heat-shock proteins (HSPs) play in protecting both cardiac and skeletal muscle from ischemic injury, contraction-induced injury, and aging, and focus on the molecular basis for the cytoprotective effects of HSPs.