Researchers who previously found that exercising for just three seconds a day, five days a week, improved muscle strength have undertaken a new study to determine the minimum number of days of three-second exercise you need to do to reap the benefits.
In 2022, researchers from Australia’s Edith Cowan University, in collaboration with Niigata University of Health and Welfare, Japan, found that doing eccentric bicep contractions for just three seconds a day for five days a week significantly improved muscle strength.
In a bicep curl, eccentric (muscle lengthening) movement occurs while you’re lowering your arm down toward your waist, slowly and with control. The arm curling upward toward the shoulder is a concentric (muscle-shortening) movement. An isometric contraction is one without motion, with no change to muscle length.
As if confirming the benefits of doing only three seconds of daily exercise five days a week wasn’t enough, now the research team has revisited their previous study to answer the question: how many days a week do I have to do my three seconds of exercise to see benefits?
“Our previous work has shown that regular, shorter exercise is more beneficial than one or two big training sessions in a week,” said Kazunori (Ken) Nosaka, one of the study’s co-authors. “Now, we have a clearer idea of where the tipping point is where you start to see meaningful benefits from such a minimal exercise.”
The researchers recruited 26 healthy young adults, including 13 participants from the previous study. Using an isometric dynamometer, which measures limb strength, participants did one three-second bicep contraction using their dominant arm either two days a week or three days a week for four weeks. After each eccentric contraction, the lever arm of the isokinetic dynamometer passively returned the elbow joint to the starting position.
They found that those who performed the exercise two days a week saw no significant changes, but the three-day-a-week group saw a small but significant increase in concentric strength (2.5%) and eccentric strength (3.9%), but no significant increase in isometric strength.
“These new results suggest at least three days a week are required, at least for the single three-second eccentric contraction training,” Nosaka said.
While still producing an increase in strength, the three-day-a-week regime doesn’t compare to exercising five days a week, which produced improvements in eccentric, concentric and isometric strength of more than 10% in each category. But the researchers say that this doesn’t necessarily mean that everyday exercise will improve results further.
“Muscle adaptations occur when we are resting, so muscles need rest to improve their strength and muscle mass,” said Nosaka. “It should be noted that the exercise was only three seconds, so the rest between exercises in the study was close to 28,800 times more than the exercise time. But muscles do appear to like to be stimulated more frequently, especially for the small volume of muscle strengthening exercise.”
More research is needed to see whether the study’s findings apply to other exercise types and frequencies. In the meantime, the researcher say that even a small amount of exercise is good for our health.
“If it is not possible to have 20 minutes a day for exercise, even five minutes a day makes a different for fitness and health,” Nosaka said. “Of course, more studies are needed to confirm this, but our recent studies show the importance of accumulating small amount of exercise as frequently as possible in a week. It is important to note that even a very small amount of exercise can make a difference to our body, if it is performed regularly.”
The study was published in the European Journal of Applied Physiology.
Source: Edith Cowan University
