Effects of Aging and Training on Muscle Shortening Properties

Event Center A & B

Mammalian muscles are extremely plastic, rapidly remodeling in response to exercise, disuse, or aging. Aging is associated with a decline in muscle performance, whereas exercise often results in mechanical or energetic changes that enhance performance. I aim to understand how exposures to regular exercise, and the genetic propensity for exercise, counteract age-related declines in muscle performance. Although numerous studies have documented agerelated changes to muscle and locomotor performance, our understanding of how genetics and exercise alter normal muscle aging is limited. Although the basic contractile machinery of skeletal muscles is highly conserved across vertebrate evolution, variation in fiber type composition provides the necessary variation in force, speed and efficiency needed to perform diverse functions. Fiber-type composition can vary among different individuals and can change rapidly in response to a muscle’s loading conditions. Therefore, fiber type composition is an expressed phenotype based on both genetic history and changes to gene expression patterns. Despite knowing fiber type composition is an important determinant of locomotor performance, it has been difficult to discern the effect of an individual’s genotype from their mechanical history. My proposed dissertation project aims to evaluate the role of genetics and plasticity on physiologically relevant traits both across generations and within an individual.