The Study:  Differential Effects of Heavy VS. Moderate Loads on Measures of Strength and Hypertrophy in Resistance-Trained Men.                   

The Facts:

a. The authors wished to look at the difference in the effects of moderate and heavy weights (loads) in the development of strength and muscular size in subjects who were already involved in weight training.

 b. 19 subjects

 c. For the heavy loads group the weight was such that the subject could only complete 2 to 4 repetitions for each set of exercise. (i.e. heavy enough to only allow them to lift the weight 2 to 4 times in good form before they had to set it down.)

 d. The moderate loads group used a weight that allowed the completion of 8 to 12 repetitions for a set.

 e. The subjects worked out three days per week.

 f. On each day they used the following exercises: “Flat barbell press, barbell military press, wide grip lat pulldown, seated cable row, barbell back squat, machine leg press, and machine leg extension.”

 g. The subjects performed 3 sets of each exercise.

 h. They worked out three times a week for 8 weeks.Exercise sessions were not on consecutive days, for example Monday, Wednesday and Friday.

 i. At the end of the study both groups had improved their strength, as measured by the most weight [maximal weight] they could lift one time, in the bench press and squat but the heavy lifters group saw a greater improvement in strength.

 j. When they tested for muscular endurance at the end of the study using a weight that was 50% of the maximal weight they could lift in the bench press and squat the two groups showed about the same improvement.

 k. Muscle thickness of the elbow flexors increased significantly in the moderate group but not in the heavy group.

 l. Muscle thickness in the lateral thigh increased with both groups with the “MODERATE showing a large effect and HEAVY showing a small effect.”

 m. The authors concluded that the mechanisms were unknown but that training closer to the maximum amount that the subjects could use for one repetition helped to maximize the strength gains while the “increases in muscle size seem to be driven more by higher training volumes, at least up to a certain threshold.”

 Take Home:

You must understand your goals to maximize your results. The heavier group maximized strength gains and the moderate group maximized muscle thickness gains.

 Reviewer's Comments: You might wonder why I have reported on two of these muscle building studies recently. Well, the more we learn about muscle and strength building the more we will tend to find things to help rehab our patients.

Reviewer:  Roger Coleman DC

Editor’s Comments: Most rehab applications will not require our patients to build large, hypertrophied, musculature. Generally, we are more interested in building strength and/or endurance. This study (as well as SIB# 361) is showing us that more training volume isn’t necessarily better. In fact, more exercises, sets, activities than necessary may actually be counterproductive by discouraging patient compliance with our recommendations.

 Editor: Mark R. Payne DC

 Reference: Schoenfeld BJ, Contreras B, Vigotsky AD, Peterson M. Differential Effects of Heavy Versus Moderate Loads on Measures of Strength and Hypertrophy in Resistance-Trained Men. J Sports Sci Med  2016 Dec 1;15(4):715-722. eCollection 2016 Dec.

 Link to Abstract: https://www.ncbi.nlm.nih.gov/pubmed/27928218