Musculoskeletal fitness involves the bones and muscles working together to perform work and include four components: strength, endurance, power and flexibility. Muscular strength is the maximum amount of weight that a muscle or group of muscles can move in a single effort. A simple hand-grip tool can be used to measure static muscle strength when the muscle is in a specific position. Grip strength is calculated from the highest right- and left-hand scores, in kilograms. Muscular endurance is the ability of a muscle group to keep moving a lighter weight repeatedly without getting exhausted. Common tests to determine upper body and trunk endurance include the push-up and partial-curl up tests, which count total number completed. Muscular power is the ability of a muscle or group of muscles to produce force quickly, typically measured in amount of work produced per unit of time, also known as watts (W). The vertical jump assesses muscular power in the legs by comparing the difference in jumping reach height to standing reach height (in centimeters). Final scores for all musculoskeletal fitness measures are compared to normal values, based on sex and age, to determine a rating. Besides improved athletic performance, improved musculoskeletal fitness is associated with increased bone mineral density (reduced risk of osteoporosis), improved metabolic rate and glucose tolerance, increased flexibility and better overall functional independent health for enhanced quality of life.