Conventional training wisdom breaks down set, repetition and intensity schemes for 3 basic qualities; strength, hypertrophy and muscular endurance. Power development is a quality that does have its own guidelines, but these tend to get confusing based on the type of movement one performs. For example, power development can involve intensity ranges >85% of 1RM if Olympic Lifts are being performed. In contrast, exercises like jump squats typically use around 30% of 1RM. So for the sake of simplicity and within the context of this article, we will stick with only strength, hypertrophy and muscular endurance guidelines (displayed in the table below).
|Strength||>85%||3-6 sets||<6 reps|
|Hypertrophy||70-84%||3-6 sets||6-12 reps|
|Muscular Endurance||<70%||2-3 sets||>12 reps|
However, recent research has been challenging conventional training wisdom when comparing hypertrophy training versus strength training for changes in muscle mass. A study recently published in the Journal of the Federation of American Societies for Experimental Biology split 29 resistance trained men into a hypertrophy group and a strength group. The hypertrophy group performed higher volume during sessions with 4 sets of 10-12RM. The strength group performed less volume with higher intensity with 4 sets of 3-5RM. Before and after the 8-week training program, muscle thickness of the vastus lateralis and rectus femoris muscles was evaluated. In addition, various hormones (e.g., testosterone, growth hormone, insulin, IGF-1 and cortisol) were measured at baseline, immediately post-exercise and again at 30 and 60 minutes post-workout.
The results showed that cortisol and GH showed a reduced response following the hypertrophy training while a decrease in the responses of IGF-1 was observed for the strength group. The strength group experienced significantly greater increases in lean body mass, leg mass, muscle thickness and cross-sectional area compared to baseline measures. No significant differences in any of these variables were observed for the hypertrophy training group.
This study suggests that resistance-trained men appear to respond more favorably to strength training for inducing improvements in muscle mass compared to traditional hypertrophy training. This may be due to greater recruitment of high threshold motor units during higher intensity exercise. Regardless, this is only one of several recent studies that is finding that heavier weight for fewer reps is equal to or superior to traditional hypertrophy training for muscle growth.
Mangine, G., Gonzalez, A., Townsend, J., Wells, A., Jajtner, A., Fukuda, D., … & Hoffman, J. (2015). Comparison of Training Intensity Versus Training Volume on Endocrine and Muscle Growth Changes in Trained Men. The FASEB Journal, 29(1 Supplement), 677-28. Chicago