General Principles of Strength Training

What the Science Says About Weights and Strength Training

The Deadlift
Deadlifting. Photo: (c) Paul Rogers

This article, the first in a series, takes a look at the position stand of the American College of Sports Medicine titled Progression Models in Resistance Training for Healthy Adults, 2009. This is a summary of the evidence, from a well-qualified group of experts, for the effectiveness of various procedures and practices in resistance and weight training programs.

The ACSM Position Stand on Weight Training and Resistance Training

This article summarizes ACSM guidelines for training characteristics focusing on training for strength; with hypertrophy (muscle building), power, and strength endurance discussed in other documents.

Note that in this version of the ACSM stand, the authors have graded the quality of the evidence as follows:

  1. A - Best class of evidence (randomized controlled trials (RCT))
  2. B - Second level of evidence (fewer RCT)
  3. C - Third level (observational only, not RCT)
  4. D - Least quality of evidence (panel consensus judgment, clinical experience)

RT stands for "resistance training" in the following discussion.

Muscular Strength

Muscular strength is the ability of the neuromuscular system to generate force. The magnitude of strength development is dependent on the the prescription of muscle actions, intensity, volume, exercise selection and order, rest periods between sets, and frequency.

Muscle Action

"Evidence category A. For progression during resistance for novice, intermediate, and advanced individuals, it is recommended that concentric, eccentric, and isometric muscle actions be included."

Muscle Loading

"Evidence category A. It is recommended that novice to intermediate individuals train with loads corresponding to 60-70% of 1 RM for 8-12 repetitions and advanced individuals cycle training loads of 80-100% of 1 RM to maximize muscular strength.
Evidence category B. For progression in those individuals training at a specific RM load, it is recommended that a 2-10% (lower percent for small muscle mass exercises, higher percent increase for large muscle mass exercises) increase in load be applied when the individual can perform the current workload for one to two repetitions beyond the target number on two consecutive training sessions."

Training Volume

"Evidence category A. It is recommended that one to three sets per exercise be used by novice individuals initially.
Evidence category B. For progression into intermediate to advanced status, data from long-term studies indicate that multiple sets be used with systematic variation of volume and intensity over time. To reduce the risk of overtraining, a dramatic increase in volume is not recommended. It is important to point out that not all exercises need to be performed with the same number of sets, and that emphasis of higher or lower volume is related to the program priorities of the individual as well as the muscle(s) trained in an exercise movement."

Exercise Selection

"Evidence category A. Unilateral and bilateral single- and multiple-joint exercises should be included in RT with emphasis on multiple-joint exercises for maximizing overall muscle strength in novice, intermediate, and advanced individuals."

Free Weights and Machines

"Evidence category A. For novice to intermediate training, it is recommended that free-weight and machine exercises are included."
Evidence category C. For advanced RT, it is recommended that emphasis be placed on free-weight exercises with machine exercises used to compliment program needs

Exercise Order

"Evidence category C. Recommendations for sequencing exercises for novice, intermediate, and advanced strength training for total body (all muscle groups trained in the workout), upper/lower body split (upper-body musculature trained 1 d and lower body musculature trained another day), and muscle group split (individual muscle groups trained during a workout) workouts include large muscle group exercises before small muscle group exercises, multiple-joint exercises before single-joint exercises, higher-intensity exercises before lower-intensity exercises, or rotation of upper and lower body or agonist- antagonist exercises, that is, exercise performed for a muscle group followed by an exercise for the opposing muscle group."

Rest Periods

"Evidence category B. For novice, intermediate, and advanced training, it is recommended that rest periods of at least 2-3 min be used for core exercises using heavier loads (those exercises included specifically to improve maximal strength such as the squat and bench press).
Evidence category C. For assistance exercises (those exercises complimentary to core exercises), a shorter rest period length of 1-2 min may suffice."

Velocity of Muscle Action

"Evidence category A. For untrained individuals, it is recommended that slow and moderate velocities be used.
Evidence category B. For intermediate training, it is recommended that moderate velocity be used for RT.
Evidence category C. For advanced training, the inclusion of a continuum of velocities from unintentionally slow to fast velocities is recommended. The velocity selected should correspond to the intensity and the intent should be to maximize the velocity of the concentric muscle action."

Frequency of Muscle Action

"Evidence category A. It is recommended that novice individuals train the entire body 2-3 d/wk.
Evidence category B. It is recommended that for progression to intermediate training, a frequency of 3-4 d/wk be used (3 d if using a total-body workout, 4 d if using a split routine thereby training each major muscle group twice).
Evidence category C. It is recommended that advanced lifters train 4-6 d/wk. Elite weightlifters and bodybuilders may benefit from using very high frequency, for example, two workouts in 1 d for 4-5 d/wk."

For a review of weight and resistance training fundamentals, you can read the beginner documentation.


Nicholas Ratamess, Brent Alvar, Tammy K. Evetoch Terry J. Housh, W. Ben Kibler, William J. Kraemer, N. Travis Triplett. Progression Models in Resistance Training for Healthy Adults. Medicine & Science in Sports & Exercise: March 2009, Volume 41, Issue 3, pp 687-708.

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