Progressive resistance exercise (PRE) is a method of increasing the ability of muscles to generate force. However, the effectiveness and safety of PRE for clients of physical therapists are not well known. The purpose of this article is to review the evidence on positive and negative effects of PRE as a physical therapy intervention. Electronic databases were searched for systematic reviews on PRE and any relevant randomized trials published after the last available review. The search yielded 18 systematic reviews under major areas of physical therapy: cardiopulmonary, musculoskeletal, neuromuscular, and gerontology. Across conditions, PRE was shown to improve the ability to generate force, with moderate to large effect sizes that may carry over into an improved ability to perform daily activities. Further research is needed to determine the potential negative effects of PRE, how to maximize carryover into everyday activities, and what effect, if any, PRE has on societal participation.