Three seconds of exercise a day makes muscles stronger, study suggests

Can three seconds of resistance exercise a day really increase our muscle strength?

The question is based on a new small-scale study of very short duration weight training. In the study, men and women who contracted their arm muscles to the maximum for a total of three seconds a day strengthened their biceps by up to 12% after one month.

The study’s findings add to growing evidence that even minuscule amounts of exercise, as long as it’s intense enough, can benefit health.

I’ve written about the unique ways our muscles, heart, lungs and other parts of the body react to four seconds of very intense cycling training, for example, or ten seconds of intense sprinting, and how super-short workout sessions like this can trigger the biological responses that lead to better fitness levels.

But almost all of that research focused on aerobic exercise and usually involved interval training, a type of training in which rapid, intense bursts of effort are repeated and interspersed with rest.

So far, there has been far less research into super-brief weight training or whether a single, very short bout of intense resistance exercise can increase muscle strength or just waste valuable seconds of our lives.

For the new study, published in February by the Scandinavian Journal of Medicine & Science in Sports, scientists led by Masatoshi Nakamura of Niigata University of Health and Welfare in Niigata (Japan) invited 39 sedentary but healthy college students to do three seconds a day. of training with weights. They recruited ten additional untrained students to serve as a control group.

Volunteers who exercised met in the lab daily Monday through Friday to do strength and weightlifting tests. They sat on a device called an isokinetic dynamometer, which has a long lever-like arm that can be pushed and pulled up or down, with varying levels of resistance, allowing researchers to precisely control the exerciser’s movements and effort.

The volunteers manipulated the lever with weights, using all their strength, tensing and contracting their biceps as much as possible. Some of the participants lifted the weight of the lever slowly, as if it were a dumbbell, producing a so-called concentric contraction, which means that the biceps contracted with their effort.

Other volunteers slowly lowered the lever, creating a so-called eccentric contraction. This occurs when a person stretches a muscle, such as when lowering a dumbbell, and tends to be more strenuous. A third group of volunteers held the weight of the lever in the air, fighting gravity, in a type of contraction in which the muscle does not change in length.

Each of the participants did their biceps exercise for a total of three seconds.

That was the total of their daily training. Participants repeated this very short workout once a day, five times a week, for a month, for a total of 60 seconds of weight training. They didn’t do any other kind of exercise.

After a month, the researchers retested the strength of all participants’ arms.

Those three-second workouts modified the volunteers’ biceps. The groups that lifted the weights or held them in the air were between 6% and 7% stronger. But those who did the eccentric contractions, lowering the lever the same way you lower a dumbbell from the shoulder, showed markedly greater gains. His biceps were nearly 12% stronger, in all.

These improvements might seem small, but they would be biologically significant, especially for people who have never done weight training before, said Ken Nosaka, a professor of exercise and sports science at Edith Cowan University in Joondalup, Australia, who collaborated on the study.

“A lot of people don’t do any resistance training at all,” he said, and starting with very short workouts can be an effective way to start a strength training regimen.

“Every muscle contraction counts,” he says, and contributes to strength gains, assuming you lift a weight that’s close to the maximum you can and the lift takes at least three seconds.

The three-second workout can also be useful as a temporary resource to help conserve or even increase the strength of the arms of all of us who live overloaded with work or family commitments and can’t go to a gym.

According to Nosaka, the exercise routine is easy to recreate at home and doesn’t require a dynamometer. Just find a dumbbell that’s heavy for you — start with one that weighs ten or five pounds, for example, if you’ve never done weight training before. “Lift it with both hands,” Nosaka said, and then lower it with one hand, counting three seconds, to complete a short, intense, strenuous eccentric contraction.

But this method has some obvious limitations. The volunteers who participated in the study got stronger but did not gain muscle mass.

“Strength gain is just one result” of resistance exercise, said Jonathan Little, a professor of health science and exercise at the University of British Columbia at Kelowna, who studied very short workouts but did not participate in this experiment.

More traditional weight training often also leads to increased muscle mass, which has additional benefits for metabolism and other aspects of long-term health and well-being.

It is also worth noting that the study focused only on the biceps of the participants. It is not known whether other muscles, especially in the legs, would be strengthened after a few seconds of intense “lifting”.

More generally, presenting physical exercise as something that we must do in the shortest possible time can make exercise sessions seem like just another task to be accomplished, and which we can therefore more easily put aside.

Nosaka said he and his colleagues plan to study whether repeating three-second contractions multiple times throughout the day increases muscle mass as well as strength. And they are studying how to translate this approach to the legs and other muscles.

In the meantime, he said, we should probably think of three seconds of daily strength training as the least we can do. “It’s definitely better to do one contraction a day than to do nothing at all,” he concluded.

Translation by Clara Allain.