American College of Sports Medicine: Recommendations for Muscular Fitness
Muscular fitness is term that describes the general health, strength, and endurance of one’s muscles but is also related to other fitness conditions, such as muscular strength which describes the amount of resistance that one’s muscles can counter, and muscular endurance, which are of greater importance when focusing on health and fitness.
Goals of a resistance training protocol should be a) make activities of daily living less stressful physiologically and b) effectively manage, attenuate, and even prevent chronic diseases, such as osteoporosis, type 2 diabetes mellitus, and obesity. For these reasons, resistance training becomes more rather than less important with age.
To accomplish these goals it is essential to develop a resistance training exercise program consisting of training taking the form of weight lifting, but also may include other exercise devices such as free weights, body weight exercises, machines with stacked weights or rubber bands that can be effective in developing muscular fitness as long as they are being properly used.
FREQUENCY OF EXERCISE
For general muscular fitness, particularly among those who are untrained, should resistance train each major muscle group (i.e., muscle groups of the chest, shoulders, upper and lower back, abdomen, hips and legs) 2-3 days a week with at least 48 hours separating the exercise training sessions for the same muscle group is recommended for adults. In this type of workout, large muscle group exercises should be performed before smaller muscle group’s exercises and multiple joint exercises should be performed before single joint exercises targeting agonist and antagonist muscle groups are recommended for adults. Following this exercise order will allow heavier loads to be used on multi joint exercises because fatigue will be less of a factor.