In brief:Part 1 of this series of articles discussed basic concepts of resistance training. This article addresses selected physiological responses and adaptations to resistance training, including changes in muscle size, muscle enzymes, maximal oxygen consumption, connective tissue, and bone mineral content. Physiological responses and adaptations have been more thoroughly studied in endurance athletes than for those in resistance training programs. However, sufficient research has been conducted to discuss some of the specific responses and adaptations, which the authors do in this paper.