Do you often find yourself thinking that you would work out more often if you simply had the time? Well, according to scientists at Australia’s Edith Cowan University and Japan’s Niigata University of Health and Welfare, all you really need to see significant strength improvements is three seconds a day.

Yes, that’s right, their new study suggests that lifting a dumbbell just once or twice a day can be enough to improve your strength, especially when it comes to combating the effects of aging. For the study, the team examined the effects of different kinds of bicep curls and identified one form of bicep curl that was remarkably effective.

The study involved 52 healthy university students, 39 of whom were made to perform a bicep curl at maximum effort for three seconds a day, five days a week, over a period of four weeks. The other 13 students performed no exercise over the same period.

Those who were made to exercise also had to complete one of three types of bicep curls, either a typical concentric curl where the dumbbell is raised toward the shoulders (this shortens the muscle), an eccentric curl where it is slowly lowered back below the hips (lengthening the muscle), or an isometric curl where the arm holds it at a 90-degree angle (this keeps the muscle stationary).

During the experiment, the researchers measured the maximum voluntary contraction strength of the subjects’ muscles before and after the four-week period—and the results were surprising.

Which bicep curl is the most efficient?

Those who were assigned the eccentric bicep had the best results by far, demonstrating significant improvements in their concentric strength (12.8 percent increase), isometric strength (10.2 percent), and eccentric strength (12.2 percent). Plus, they enjoyed an 11.5 percent boost in overall muscle strength.

That said, all exercising participants showed some improvement, with the concentric group improving their isometric strength by 6.3 percent, and the isometric group increasing their eccentric strength by 7.2 percent. However, there were no other improvements in other parts of the body, which suggests that eccentric contractions are probably the best way to gain strength if you have limited time.

“Although the mechanisms underpinning eccentric contraction’s potent effects are not clear yet, the fact only a three-second maximal eccentric contraction a day improves muscle strength in a relatively short period is important for health and fitness,” said Professor Ken Nosaka from Edith Cowan University.

“We haven’t investigated other muscles yet, but if we find the three-second rule also applies to other muscles then you might be able to do a whole-body exercise in less than 30 seconds,” Nosaka added. “Also, performing only one maximal contraction per day means you don’t get sore afterward.”

These findings could be extremely important in terms of preventing the loss of muscle mass and strength associated with aging.

Source study: Scandinavian Journal of Medicine and Science in Sports – Effects of daily 3-s maximum voluntary isometric, concentric or eccentric contraction on elbow flexor strength