Here’s some good news for anyone who does not have the time or inclination to linger in the gym and grunt through repeated, hourslong sets of various weight-training exercises in order to build muscular strength.
An inspiring new study of how much — or little — weight training is needed to improve muscles’ strength and size finds that we may be able to gain almost the same muscular benefits with a single, brief set of each exercise.
The catch is, that set has to be draining.
A set is a given number of repetitions of an individual exercise, whether that move is a bench press or biceps curl.
In general, we are advised to complete eight to 12 repetitions of an exercise during a set, with the aim of making our working muscle so tired by the end of the set that we temporarily cannot complete another repetition.
This process is known, almost poetically, as lifting to failure.
Most of us who lift weights probably have heard that, if we hope to gain size, strength and endurance in our muscles, we should aim to complete at least three sets of each exercise during a full session, meaning that we would be expending considerable sweat and time at the gym.
But there has been surprisingly little definitive science to support these notions, and much of the available research had focused on people who were new to the sport and whose muscles tend to respond vigorously to any amount of this unfamiliar activity.
Whether they and the rest of us would need to add more sets and effort once we had become accustomed to weight training if we hoped to keep augmenting our strength was not clear.
So, for the new study, which was published in August in Medicine & Science in Sports & Exercise, researchers at Lehman College in the Bronx and other institutions decided to test just how much weight training is required to continually make muscles larger and stronger.
Their first step was to recruit 34 fit young men who were not burly weight lifters but did resistance train with some regularity.
The researchers tested these men’s current muscular strength, endurance and size and then randomly assigned them to one of three different supervised weight-training routines.
The general program was simple and familiar, consisting of seven common exercises, including the bench press, lateral pull-down, machine leg press and others. A set of any of these exercises would require lifting to failure through eight to 12 repetitions.
But the “dose” of the exercises assigned to each group differed.
One group was asked to complete five sets of each exercise, with about 90 seconds of rest between sets. Their total time for a session at the gym was almost 70 minutes.
A second group was asked to complete three sets of each exercise, requiring they work out for about 40 minutes.
The third group had to finish only one set of each exercise, meaning that they were done after a brisk 13 minutes.
Each volunteer performed his given workout three times a week for eight weeks and then returned to the lab to repeat the muscle measurements.
After the two months, all of the young men were stronger, a finding that, by itself, is beguiling, since it suggests that people can continue to gain strength even if they already are experienced at resistance training.
But more interesting and surprising, the strength improvements were essentially the same, no matter how many — or few — sets the men completed.
The men who had stopped after one set gained as much strength as those who had done five sets or three.
The groups likewise showed equivalent improvements in muscular endurance, which was measured by how any times they could repeat a bench press exercise, using a low weight.
Only the size of the men’s muscles differed. Those who had completed five sets per session sported greater muscle mass than those who had done three sets or one.
But they were not noticeably stronger.
These results suggest that “there is a separation between muscular strength and hypertrophy,” or enlargement of the muscle, says Brad Schoenfeld, the director of the human performance program at Lehman College and the study’s lead author.
Your muscles can become as strong as those of someone who is burlier.
You also probably can gain this strength with one set of lifts, he says; five and even three sets were not necessary in this study to improve strength.
What was required was to strain the working muscles to limp exhaustion by the end of each set, he says. In effect, you should be physically unable to complete another repetition at that point, without resting.
“A lot of people probably do not push themselves that much” during a session at the gym, he says. “You have to reach failure” during a set for the training to succeed.
If you are new to resistance training or worried about injuring yourself, you may want to consult a trainer about proper form and how to determine the right weight for you to be lifting, he says.
Of course, this study was short term and involved young men, so we cannot know whether the results would be the same for women and older people.
Dr. Schoenfeld suspects that they should be.
“But obviously,” he says, “more studies are needed.”
Even now, though, the findings are encouraging and practical.
“It looks like 13 minutes in the gym can lead to significant improvements” in strength, he says. “That’s less than a fourth of someone’s lunch hour. Most of us can probably find that much time in our day.”