PURPOSE: To understand how menopause changes a woman's nervous system and muscles. We also want to see if hormone therapy, structured strength training exercise, or a combination of both can protect a woman's strength and physical function during this transition.

PURPOSE: To better understand the cause of muscle fatigue across the lifespan. We also want to determine whether participating in an exercise training program can improve muscle fatigue.

PURPOSE: To understand the cause of muscle fatigue in people with type 2 diabetes and prediabetes.