Muscular Strength and Endurance Training Guidelines

The American College of Sports Medicine (ACSM) recommends the following muscular strength and endurance training guidelines for developing and maintaining muscular strength and endurance in healthy adults:

Frequency of Training: 2 to 3 days per week
Note: In general, resistance training workouts should be performed on nonconsecutive days to allow for 48 hours of rest between exercise sessions involving the same muscle groups.  Some advanced routines allow for more frequent training by designing workouts based on specific muscle groups - such as upper body one day and lower body the next.

Intensity of Training: 1 to 3 sets of 8 to 12 repetition maximum (RM) with a resistance that is 70% to 80% of 1 repetition maximum (1RM)  
Note: The term repetition maximum (RM) refers to the maximal number of times a particular exercise can be repeated against a given resistance, using good form and technique, before fatigue (e.g., temporary muscle fatigue or anticipated muscle failure).   Based on previous research, a repetition continuum has been established that correlates the number of repetitions possible with exercise intensity.  For example, 16 to 20 RM relates to an intensity that is approximately 60% of that individual's 1RM, 14 to 15 RM = 65%, 12 to 13 RM = 70%, 10 to 11 RM = 75%, 8 to 9 RM = 80%, 6 to 7 RM = 85%, 4 to 5 RM = 90%, 2 to 3 RM = 95%.  Thus, 8 to12 is the theoretical maximum number of repetitions that a person can perform a particular exercise against a given resistance, using good form and technique, when that resistance is approximately 70% to 80% of that person's one repetition maximum (1RM).  Conversely, it is possible to estimate a person's 1RM based on how many times they can perform an exercise against a given resistance.  For example, if a person can only perform 9 repetitions before fatigue with a 50 pound resistance, then their 1RM would be estimated by multiplying 50 pounds times 1.80, which equals 90 pounds.  For the more serious weight lifter (athlete), a regimen of heavier weights (6-12 RM) of 1-3 sets using periodization techniques usually provides greater benefits.  For older and more frail persons (e.g., 50-60 years and above) 10-15 RM may be more appropriate.  In general, greater than 20 RM does not contribute to the development or maintenance of muscular strength and less than 5 RM does not contribute to the development or maintenance of muscular endurance.  Resistance training should utilize the progressive overload principle, that is, the resistance should be increased (by 5% to 10%) when 12 repetitions can be easily accomplished with good form and technique.

Duration of Training: 20 to 60 minutes
Note: Resistance training for the average participant should be rhythmical, performed at a moderate-to-slow controlled speed, through a full range of motion, and with a normal breathing pattern during the lifting movements.  Two common mistakes individuals often make when resistance training are: 1) performing the exercise movement too quickly and 2) sacrificing technique in order to increase resistance.  Best results are achieved by visualizing the specific muscle(s) being worked, pausing briefly before changing movement directions, and moving smoothly through both the ascending (e.g., 1 to 2 seconds) and descending (e.g., 3 to 4 seconds) portions of each exercise.  Exercise programs lasting more than 60 minutes per session appear to be associated with higher dropout rates.  Duration is dependent on the intensity of the activity; thus, lower-intensity activity should be conducted over a longer period of time (e.g., 30 minutes or more), and, conversely, individuals training at higher levels of intensity should train at least 20 minute or longer.

Mode of Activity: 8 to 10 exercises targeting the major muscle groups (e.g., chest, shoulders, arms, back, abdomen, and legs). 
Note: Resistance training should utilize the specificity principle, that is, you must exercise the specific muscles that you want to develop.  Performing exercises that work the biceps for example, will result in development of the biceps muscle and supporting structures. Therefore, it is important to follow a well rounded exercise routine that focuses on challenging all the major muscle groups. Working one muscle group at the exclusion of another (such as the biceps and not the triceps) will eventually cause a muscular imbalance that could lead to injury.  Exercises that strengthen the body's "core" (such as the upper and lower back, chest, abdominal, hips, and buttocks) should be a priority for most individuals.