The Real Driver of Muscle Growth

Most people think the primary driver for muscle growth is volume, but most of these same people define volume as the number of sets you’re performing in a training session (not counting your warm-up sets, mind you). More accurately defined, volume is sets x reps x loading (weight). Total tonnage – that’s what really determines growth. Let’s take a look at a solid study that proves it, along with defining the exact amount of volume that builds the most muscle. Study Design Barbalho, et al. separated 40 experienced female lifters into four groups. Each group trained to failure using a different amount of volume. Average Age:24-25 years old Training Experience:At least three years Length of Study:24 weeks Note that a resistance training study done for 24 weeks is very rare. The usual is 8 to 12 weeks. We’re literally looking at six months worth of training with a 100% completion rate by the subjects. That means all 40 women who started the study finished it. Fantastic. The Program Each group did a different amount of total sets per workout: 5 sets per workout 10 sets per workout 15 sets per workout 20 sets per workout The program itself was done three days a week, hitting each muscle group once a week. Monday Training A. Barbell Bench Press B. Incline Barbell Press C. Barbell Military Press The 5 set group did 2 sets of bench presses, 2 sets of inclines, and 1 set of military presses. The 10 set group did 4 sets of bench presses, 4 sets of inclines, and 2 sets of military presses. The 15 set group did 5 sets of bench presses, 5 sets of inclines, and 5 sets of military presses. The 20 set group did 7 sets of bench presses, 7 sets of inclines, and 6 sets of military presses. Thursday Training A. Lat Pulldown B. Cable Row C. Upright Row The 5 set group did 2 sets of pulldowns, 2 sets of cable rows, and 1 set of upright rows. The 10 set group did 4 sets of pulldowns, 4 sets of cable rows, and 2 sets of upright rows. The 15 set group did 5 sets of pulldowns, 5 sets of cable rows, and 5 sets of upright rows. The 20 set group did 7 sets of pulldowns, 7 sets of cable rows, and 6 sets of upright rows. Friday Training A. 45-Degree Leg Press B. Barbell Squat C. Stiff Legged Deadlift The 5 set group did 2 sets of leg presses, 2 sets of squats, and 1 set of stiff legged deadlifts. The 10 set group did 4 sets of leg presses, 4 sets of squats, and 2 sets of stiff legged deadlifts. The 15 set group did 5 sets of leg presses, 5 sets of squats, and 5 sets of stiff legged deadlifts. The 20 set group did 7 sets of leg presses, 7 sets of squats, and 6 sets of stiff legged deadlifts. Rep Periodization The scientists periodized the training so that the lifters used different rep schemes each week. Then they rotated back around each month: Week 1:12-15 reps, 30-60 seconds rest between sets Week 2:4-6 reps, 3-4 minutes rest between sets Week 3:10-12 reps, 1-2 minutes rest between sets Week 4:6-8 reps, 2-3 minutes rest between sets This periodization model was repeated six times (there’s your 24 weeks). The Results The researchers tested the women’s 10-rep max on the bench press, lat pulldown, leg press, and stiff-legged deadlift at the beginning of the study. The scientists also measured muscle thickness of the biceps, triceps, pecs, quads, and glutes. The tests and measurements were repeated after 24 weeks. This is what they found: All groups showed significant increases in all muscle thickness measurements and 10-rep max tests. There were no differences in any 10-rep max tests between the 5 and 10 set groups. The 5 and 10 set groups showed significantly greater 10-rep max increases for lat pulldowns, leg presses, and stiff-legged deadlifts than the 15-set group. For the bench press, the results from the 5, 10, and 15 set groups didn’t differ significantly, but the 20-set group tested out the worst. In fact, 10-rep max changes for the 20-set group were lower than all other groups for all exercises. As for muscle thickness improvement, as you might expect, it correlated with the strength gains. The 5 and 10 set groups showed significantly greater increases than the 15 and 20 set groups in all measured sites. Muscle thickness increased more in the 15 set group than the 20 set group in all sites. The increases in the 5-set group were higher than the 10 set group for the pecs, whereas the 10-set group showed higher increases in quadriceps muscle thickness than the 5-set group. To put this in perspective, the 20-set group exhibited about a quarter of the gains that the 10 set group did. A Possible Flaw in Their Findings? The one argument against this study is that the subjects in the 15 and 20 set groups probably did too much volume in their sessions and exceeded their capacity to recover. If the work load had been spread out over more training days in the week, the outcome could have been different. Nice try, but they didn’t exceed their maximum recoverable volume in a single session! Look at the
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