The 3/7 Method for Muscle Growth and Strength

by TC Luoma

The 3/7 Method for Muscle Growth and Strength

A scientifically proven and extremely time-efficient set/rep scheme for increasing muscle growth and strength. Check it out here.

Muscle Growth, Metabolic Stress, and Mechanical Stress

I'm a sucker for metabolic stress. If, after a workout, I'm not short of breath, don't feel sweat trickling down my temples, don't sizzle from a lactic acid burn, or exult in the glory of a pump, I get the workout equivalent of blue balls.

Just like real blue balls, it's not dangerous, but I'm a little cranky until I find sweet release. So, load me up with work, please. Let my spirit animal – a mutant crossbreeding between a mule and a beaver – shine.

That's why reading about the 3/7 method aroused my interest. It's a set-rep scheme developed by French strength coach Emmanuel Legeard in the early 2000s. It combines relatively heavy weight (mechanical stress) with very short rest periods (metabolic stress).

It's got a couple of things going for it. One, it's among the most time-efficient methods around, and two, it's got some solid research to back up its muscle-building and muscle-strengthening credentials.

What Is the 3/7 Method?

  1. After warming up, choose a weight representing about 70% of your 1RM for whatever exercise you're about to do. That usually equates to a weight you can do around 12 reps with.
  2. Do 3 reps. Rest 15 seconds.
  3. Do 4 reps. Rest 15 seconds.
  4. Do 5 reps. Rest 15 seconds.
  5. Do 6 reps. Rest 15 seconds.
  6. Do 7 reps. Rest 150 seconds (two and a half minutes).
  7. Repeat all the steps for a total of 3 times.

Why Does It Work?

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

Sound vaguely familiar? It's exactly the mechanism ascribed to the success of blood-flow restriction training (when you wrap elastic bands around a muscle before doing a set).

The incremental organization of the reps within each set are also thought to play a part in inducing a greater accumulation of metabolites, particularly by the 5th set (of the first "round" of reps), the 10th set (at the end of the second round), and the 15th set (which you hit at the end of the third round, assuming you haven't already hit failure).

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

Research: Does the 3/7 Method Make Me Stronger?

There have only been two studies conducted using the 3/7 method (the first of which was chosen as a finalist for "Paper of the Year" at the American College of Sports Medicine's annual meeting), but both showed compelling results.

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

  • Group A used a 4x6 (4 sets of 6 reps) protocol.
  • Group B used an 8x6 (8 sets of 6 reps) protocol.
  • 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 4x6 group improved their 1RM by 21.8%.
  • The 8x6 group improved their 1RM by 35.9%.
  • The 3/7 group improved their 1RM by 29.8%.

While the 3/7 group didn't "win" the competition, it still showed pretty strong results. Bear in mind, too, that this study only used one round of 3/7 training instead of the 3 rounds initially proposed by Emmanuel Legeard when he devised the method.

Research: Does the 3/7 Method Make Me Bigger?

Stragier, et al. also compared the 3/7 method to another classic set/rep scheme (8x6), this time targeting biceps curls and evaluating 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 did two rounds of 3/7 training instead of one.

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

This time, 3/7 came up on top. It resulted in 75% greater biceps growth and 83% greater strength gains than the 8x6 protocol, probably because of the additional round of metabolic stress induced by using a second round of 3/7 training.

Advantages and Disadvantages of the 3/7 Method

The studies are fairly compelling, but you might have noticed that they didn't use experienced weight trainers. That sours the results a bit because, well, you could train newbies with Campbell's soup cans and then progress them to using 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 kind of metabolic stress training appears sound. It could very well work in experienced trainees, particularly if they do three rounds of the 3/7 method (for a total of close to 75 reps!) instead of the one or two used in the studies.

One distinct advantage of the 3/7 method that you might not have considered is time efficiency. One round of 3/7 training takes somewhere between 2 and 3 minutes, whereas doing 8 sets of 6 would probably take around 20 minutes.

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

Three Critical Points

If you want to take 3/7 training out for a spin, respect these critical points:

  1. Pick the correct weight (approximately 70% of your 1RM, which usually equates to a weight you can do for 12 reps or so). You'll know you're using the right weight if you fail to hit your prescribed reps on the last one or two intra-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 probably need to do 3 rounds to reap maximum benefits.

And while the studies on the 3/7 method only used two exercises (smith machine bench presses and machine biceps curls), there's no apparent reason it shouldn't work well with any body part or any conventional exercise, with the possible exception of nut busters like squats or deadlifts.

MD-Buy-on-Amazon

References

  1. Stragier S et al. "Efficacy of a new strength training design: the 3/7 method." Eur J Appl Physiol. 2019 May;119(5):1093-1104. PubMed: 30756168.
  2. Laurent C et al. "Effect of a strength training method characterized by an incremental number of repetitions across sets and a very short rest interval." Science & Sports. 2016 Oct;31(5):e115-e121.
2 Likes

There is a major flaw in that research. The other groups did all sets with RIR 6, which eliminates a major reason for adaptation. Sure, it still works for newbies somewhat.

And the rest.
Only 2 studies
Inexperienced trainees using an advanced method
No details of how many different exercises you should use within a session
How many rounds - 1 2 3 ?
Volume - The whole thing appears to be blocks of giant sets of rest/pause.
etc

Exactly! A random rep/rest scheme supported only with weak evidences. Why 3/7, not 4/9? Why 15 sec, but not 20 or 20? Or any other random numbers?

A quick search said that this method was effective for Werner Gunthor and Valerie Adams, who are super-freaks.

If it works for grabasstic untrained people and multi-World Champions it will probably work for dudes in the middle.

I tried this today, for weighted chin ups. Honestly I think it’s a pretty poorly designed scheme, unbalanced, I’d do it with something like 5 seconds for the first rest period than 3 additional seconds for each subsequent rest period. There is too much of a difference between doing 3 reps, and doing 6 reps (soon to be 7) to have the same rest.

But it’s worth a try for something different.

1 Like

Freaks can improve using almost anything, they have the genetics. Untrained ditto since the only way is up.
The largest group are the ordinary people in the middle. There is no hard evidence this would suit them.
There are a vast number of programmes around, more strategies than in most sports IMHO. Why not pick one that has happy followers - 5/3/1, Dan John, Tactical Barbell, … Walrus, crossfit. You need to find the one that suits you.

1 Like

What happened over the course of the sets that made you want longer rest periods?

Like, did the sets get way, way harder to complete? Did it feel like half the reps were under duress?

3/7 adds up to 25 total reps, just like Prilleprin’s Chart says to do with 70%.

4/9 adds up to like 39 total reps. You would need to use low weights, like 50% or less to do all those reps. Weights that low don’t build much strength.

Not so much longer rest periods, but rests in proportion to the work done. If a weight can be done that you do 7 reps 15 seconds after just doing 6 reps, it means the earlier sets had to have been fluff.

I’m pretty adapted to shorter rest periods too, for example compounds 1 min, the rest 30 or 45 seconds with a lot of superset work too. I’d predict the average gym goer would need to do closer to 50% 1RM to hit the final sets, meaning the first sets were basically a waste of time