Muscle Strength & Endurance Explained By The American College Of Sports Medicine

Muscular Strength & Muscular Endurance as Explained by the American College of Sports Medicine Muscular strength and endurance are health-related fitness components that may maintain or improve the following: • • • • •

Bone mass, which is related to osteoporosis Glucose tolerance, related to type 2 diabetes (diabetes mellitus) Musculotendious integrity, which is related to a lower risk of injury, including lower back pain The ability to carry out the activities of daily living, which is related to selfesteem The fat free mass and resting metabolic rate, which are related to weight management

The American College of Sports Medicine (ACSM) has melded the terms muscular strength and muscular endurance into the category termed “muscular fitness” and included it as an integral portion of total health related fitness in a position stand on the quantity and quality of exercise to achieve and maintain fitness. Muscular strength refers to the ability of the muscle to exert force. Muscular endurance is the muscle’s ability to continue to perform for successive exertions or many repetitions. Traditionally, tests allowing few (<3) repetitions of a task prior to reaching momentarily muscular fatigue have been considered strength measures, whereas those in which numerous repetitions (>12) were performed prior to momentarily muscular fatigue were considered measures of muscular endurance. However, the performance of a maximal repetition range (i.e. 4,6, or 8) also can be used to assess strength. Muscle function tests are very specific to the muscle group tested, the type of contraction, the velocity of the muscle movement, the type of equipment, and the joint range of motion. Results of any one test are specific to the procedure used, and no single test exists for evaluating total body muscular endurance or muscular strength. Unfortunately, few muscle endurance or strength tests control for repetition duration (speed of movement) or range of motion, thus results are difficult to interpret. Individuals should participate in familiarisation/practice sessions with the equipment, and adhere to a specific protocol (including a predetermined repetition duration and range of motion) in order to obtain a reliable score that can be used to track true physiologic adaptations over time. The standardised conditions or protocol should include: • • • • • •

Strict posture Consistent repetition duration (movement speed) Full range of motion Use of spotters (when necessary) Equipment familiarisation Proper warm-up

A change in one’s muscular fitness over time can be based on the absolute value of the external load or resistance (e.g. Newtons, kilograms, or pounds), but when comparisons are made between individuals, the values should be expressed as relative values (per kilogram of body-weight [kg/kg]). In both cases, caution must be used in the interpretation of the scores because the norms may not include a representative

sample of the individual being measured, a standardised protocol may be absent, or the exact test being used (free weight versus machine weight) may differ. This exert has been reproduced from the ACSM’s Guidelines for Exercise Testing and Prescription (2007) Lippincott, Williams, and Wilkins: London. ISBN 13:978-0-7817-4590-1