Hypertrophy Rep Range 10 -12 Reps: Fact or BroScience?

by: Robbie Durand

Sometimes when I go to the gym, I see the same person doing the same routine every week. Monday, I can already see the same individuals on the bench doing the same weight. There have been some remarkable bodybuilders that went on win the Olympia many times, yet they trained the same way every year. Some bodybuilders have tried new rep range variations only to go back to their old school style of training. A new variety of training called undulating periodization is a method of training in which a lifter changes the sets, reps, and rest periods, every time they go to the gym. There have been some studies that have found that exercise variety enhances muscle growth whereas other studies have concluded that it made no difference. For example, one study reported that after ten weeks of either keep workouts the same and weekly using training variety made significant increases in strength and power, but improvements in lower-body strength were significantly greater in the variety group (+27.7%) compared with the group that kept things the same (+15.2%). Both groups significantly increased arm muscle hypertrophy whereas improvements in thigh muscle size were significant in the weekly variety group only. Results of this study indicate that the weekly variety training model is more effective than the block periodization model for increasing maximal strength and muscle size in the lower body. So if you’re looking to maximize gains, a lifter should be incorporating a broad range of resistance exercise variable and changing sets, repetitions, and training volume.

There may be an advantage to combining low, medium, and high repetitions in a long-term training routine. One of the leading experts in muscle hypertrophy, Dr. Brad Schoenfeld, recently investigated just this topic. In his paper titled, “ Effects of Varied Versus Constant Loading Zones on Muscular Adaptations In Well-Trained Men .” compared well-trained athletes who were assigned to either a protocol of combination of loading zones vs. one employing a constant medium-repetition loading zone on muscular adaptations in resistance-trained men.

Subjects were pair-matched according to baseline squat strength and then randomly assigned to 1 of 2 experimental groups:

-a constant-rep routine that trained using 8–12 repetition maximum per set or

-a varied-rep routine that trained with 2–4 RM per set on Day 1, 8–12 RM per set on Day 2, and 20–30 RM on Day 3.

The resistance training protocol consisted of 7 exercises per session targeting all the main muscle groups of the body. The exercises performed were: at barbell press, barbell military press, wide grip lat pulldown, seated cable row, barbell back squat, machine leg press, and machine knee extension. Training for both routines was performed three times per week on nonconsecutive days for eight weeks. Three sets were performed for each exercise. Sets were carried out to the point of momentary concentric muscular failure.

At the end of the study, the results were shocking. The researchers found no significant differences between the two conditions, indicating that both strategies are equally suitable for increases in muscle hypertrophy, strength, and endurance. The researchers stated that “there were no differences between variety workouts and constant loading workouts.” The researcher did say that the results may be different if the study had been carried out longer than eight weeks, but future research needs to be conducted. The present results suggest that comparable hypertrophic, strength and endurance adaptations occur when a varied training protocol is compared against a constant loading program at 8–12 RM; however, trends suggest that improved muscular endurance may occur in protocols that employ high repetition ranges. Of interest, VARIED loading schemes may provide comparable adaptations with reduced volume-load, indicating a training stimulus of greater efficiency as compared to training exclusively in a fixed repetition range.

Key Points: The researchers found that repetitions performed in the 10-12 repetition range did not lead to greater muscle mass than the group trained with a combination of low, medium, and high repetitions. 10-12 repetition range is no longer the “golden rep range” for putting on muscle mass.