Pain in Athletes INtervention (PAIN): A Randomized Crossover Clinical Trial in Aging Former Athletes, Master's Athletes, and Nonathletes

The goal of this clinical trial is to determine how male and female former athletes experience pain and respond to moderate-intensity exercise (strength versus aerobic) compared with both current master's athletes and nonathletes. The main questions this study aims to address are: 1. How do former athletes, master's athletes, and nonathletes experience pain? 2. How do different types of moderate-intensity exercise (strength versus aerobic exercise) influence pain in former athletes, master's athletes, and nonathletes? Participants will complete 3 different testing sessions: 1. Baseline testing including assessments of strength, cardiorespiratory fitness, and pain; 2. Strength exercise: pain assessments will occur before and after moderate-intensity strength training exercise; 3. Aerobic exercise: pain assessments will occur before and after moderate-intensity aerobic exercise. There will be a washout period of approximately one week or greater between each of the three different testing sessions. The order of conditions (strength versus aerobic exercise) will be randomized (crossover randomized trial design).