The 3/7 Method for Muscle Growth and Strength

The short intervals used in the 3/7 method are believed to induce a greater amount of cumulative fatigue-related metabolites such as lactate, hydrogen ions, and inorganic phosphate.

Sound vaguely familiar? It is exactly the mechanism attributed to the success of blood flow restriction training (when you wrap rubber bands around a muscle before doing a set).

The incremental organization of reps within each set is also thought to play a role in inducing greater accumulation of metabolites, particularly in the fifth set (of the first “round” of reps), the tenth set (at the end of the second round), and set 15 (which you hit at the end of the third round, assuming you haven’t missed yet).

All of this metabolic stress initiates anabolic signaling that leads to muscle hypertrophy.

Only two studies have been done using the 3/7 method (the first of which was chosen as a finalist for “Paper of the Year” at the annual meeting of the American College of Sports Medicine), but both showed convincing results.

Laurent, et al. compared the 3/7 method with two more traditional training methods. They divided 38 healthy young men into three separate groups. Each group trained bench press twice a week for 8 weeks:

• Group A used a 4×6 protocol (4 sets of 6 repetitions).
• Group B used an 8×6 protocol (8 sets of 6 repetitions).
• Group C used the 3/7 protocol.

Each group used 70% of their 1RM and rested 150 seconds between sets (or, in the case of the 3/7 method, between rounds).

• The 4×6 group improved their 1RM by 21.8%.
• The 8×6 group improved their 1RM by 35.9%.
• Group 3/7 improved their 1RM by 29.8%.

Although group 3/7 did not “win” the competition, they still showed pretty solid results. Note, too, that this study only used a 3/7 training round instead of the 3 rounds initially proposed by Emmanuel Legeard when he devised the method.

Stragier, et al. also compared the 3/7 method with another classic set/rep scheme (8×6), this time focusing on biceps curls and assessing both strength and muscle thickness.

Forty-three untrained subjects, divided into two groups, trained machine biceps curls twice a week for 12 weeks. However, unlike the Laurent study described above, the subjects in this study performed two rounds of 3/7 training instead of one.

As in the Laurent study, both groups used training weights that approached 70% of their 1RM.

This time, 3/7 made it to the top. It resulted in 75% more biceps growth and 83% more strength gains than the 8×6 protocol, likely due to the additional round of metabolic stress induced by using a second round of 3/7 training.

The studies are pretty convincing, but you may have noticed that they didn’t use experienced weight trainers. That sours the results a bit because, well, you could train novices on Campbell’s soup cans and then have them use Progresso Rich and Hearty soup cans, and even that amount of anemic training would result in some significant gains in strength. and hypertrophy.

Still, the hypothesis behind this type of metabolic stress training seems solid. It could work very well for experienced trainees, particularly if they do three rounds of the 3/7 method (for a total of about 75 reps!) instead of the one or two used in the studies.

One distinct advantage of the 3/7 method that you may not have considered is time efficiency. A training round of 3/7 takes 2-3 minutes, while doing 8 sets of 6 would probably take around 20 minutes.

Of course, adding additional 3/7 rounds of training would add to that 2 or 3 minute total, but it’s still a pretty quick workout.

If you want to do 3/7 of training to go for a ride, respect these critical points:

1. Pick the right weight (approximately 70% of your 1RM, which generally equates to a weight you can do for 12 reps or so). You’ll know you’re using the correct weight if you don’t hit the prescribed reps on the last one or two inside sets of rounds two or three.
2. Allow only 15 seconds between each “intra-set” and allow 150 seconds (two and a half minutes) between rounds.
3. Experienced trainees will probably need to do 3 rounds to get the maximum benefits.

And while the studies on the 3/7 method only used two exercises (Smith machine bench press and machine bicep curl), there’s no apparent reason why it wouldn’t work well with any body part or any conventional exercise, with the possible exception of nut busters like squats or deadlifts.