Abstract : Athletes' physical fitness, especially VO2max and muscle endurance, must be increased or maintained because it determines the ability of an athlete to carry out their activities. Physical fitness needs special attention because it is an important element in almost all sports. To determine the effect of physical exercise on changes in VO2max, muscle endurance, and hemoglobin in athletes. This research is a quasi-experimental research with a pre and post-test one-group design with two measurements, before exercise, and after exercise. A total of 40 samples were recruited to participate in this study with predetermined inclusion and exclusion criteria. Physical exercise was given 3 times a week for 2 months. VO2max with bleep test, muscle endurance with half squat jump, and Hemoglobin with routine blood test Results. Physical exercise is very effective on athlete's muscle endurance but is not effective for increasing VO2max and hemoglobin of athletes at the Makassar Student Sports Education and Training Center (PPLP).