It sounds like the sort of fishy claim in a late-night infomercial or a clickbait ad: You can get the same strength gains from a 13-minute workout that you would from a 70-minute workout!
Yet that’s the conclusion of a study published in the journal Medicine & Science in Sports & Exercise, which explored how muscles adapt to different volumes of resistance training.
Every meathead in the gym has a different opinion on the optimum workout for big, strong muscles. Is it better to do a more repetitions (the number of times you repeat an individual exercise), or less? More sets (the number of groups of repetitions), or less?
Surprisingly few studies have examined the question, and their results often seem to conflict each other.
An added problem is that a lot of research into muscle and strength is performed on people who’ve rarely lifted weights — who are likely to score impressive initial results no matter what they do (a phenomenon dubbed "newbie gains"). Those studies aren’t much use to more experienced weightlifters looking for methods to push through a plateau.
So the new study, led by researchers from New York City’s Lehman College, set out to determine how everyday fellas who already hit the gym three times a week would respond to different resistance training patterns.
The 45 men were given a full-body, supervised gym program to do three times a week, consisting of seven standard exercises: barbell bench press (which hit their chests), barbell military press (shoulders), wide-grip lateral pulldown and seated cable row (backs), and barbell back squat, machine leg press and unilateral machine leg extension (legs).
The men were all instructed to do between 8-12 repetitions of each exercise, with about a 90-second rest in between.
But here’s where the men’s programs differed: a third of them were put into a low-volume group, and did only one set of each exercise, for a workout totalling about 13 minutes.
A moderate-volume group did three sets, and worked out for 40 minutes; and a third high-volume group did five sets, for about a 70-minute workout.
All groups were told to work to failure — until they couldn’t complete another rep, in other words. In practice, that meant the low-volume group performed more exhausting one-off sets than the other groups.
They followed their workout programs for eight weeks (with no particular diet instruction, other than making sure they were consuming enough protein), then underwent tests to measure their muscle strength, size and endurance.
The researchers predicted the high-volume group would gain the most strength — but according to the paper, participants’ "gains in muscular strength were strikingly similar" regardless of whether they followed the low, moderate or high-volume training.
"These findings indicate that resistance-trained individuals can markedly enhance levels of strength by performing only approximately 39 minutes of weekly resistance training, with gains equal to that achieved in a fivefold greater time commitment," the research team wrote.
The experiment indicates you might not need to spend hours in the gym to boost muscle strength, if you’re willing to work extremely bloody hard in that shorter amount of time.
However, boosting muscle size is a different matter. Contrary to what many people think about muscles, growth and strength aren’t quite the same thing — which is why some of the strongest Australian Ninja Warrior competitors are relatively lean, for example.
The researchers noted "a dose-response relationship between volume and hypertrophy" — which, translated into plain English, means the study participants in the high-volume group increased their muscle sizes the most.
So if you care more about getting swole than getting strong, you probably do need to commit to solid gym time.
Although more research is needed to determine whether older people and women would earn the same resistance-training benefits, the study indicates that that old excuse — "I just don’t have time to get strong" — is unlikely to hold much water.