ABSTRACT
Muscular strength is defined as the ability to generate force against a resistance and can be thought of in terms of force output by an individual skeletal muscle or a group of skeletal muscles exerting force in a coordinated pattern. Strength is influenced by both intrinsic (i.e., genetic) and extrinsic (i.e., environmental) factors. This book’s previous chapter (Chapter 18) explored the heritability of muscle size and strength traits at baseline and changes in these traits following exercise training. This chapter will further explore muscular strength as a multifaceted trait that is affected by underlying components such as muscle mass, neuromuscular activity patterns, and executable skill in performing a variety of tasks. Muscle size and strength are generally positively related to one another (especially at baseline), but this relationship is complex with high intersubject variability, especially during training or detraining. This chapter will serve as a primer to identify important components of muscle strength, highlight biological pathways that modify strength at baseline and strength changes with training, and identify molecular and genetic modifiers of strength. We refer the reader to later chapters for expanded discussions of modifiers of complementary traits such as muscle size (Chapter 20) and neuroendocrine status (Chapter 21).
