Assess your fitness across nine physiological dimensions—from movement quality to VO2 max—using practical, low-cost tests you can perform today. Dr. Andy Galpin breaks down how to measure strength, power, endurance, and muscle mass, then reveals which areas need priority training for long-term health and peak performance. The nine components of fitness are skill, speed, power, strength, hypertrophy, muscular endurance, anaerobic capacity, maximal aerobic capacity, and long-duration endurance; deficiency in any area limits overall performance.