The sporting volunteers gathered in the lab for strength testing and weightlifting, of some sort during the work week. They sat at a machine called an isokinetic dynamometer, which has a long lever arm that can be pushed and pulled, up or down, with varying levels of resistance, allowing researchers to accurately monitor people’s movements and efforts.
The volunteers manipulated the weighted lever with all their strength, tensing and tightening their biceps as best they could. Some participants slowly lifted the weight off the lever, like curling a barbell, producing what’s called a concentric contraction, meaning the biceps shortened as they worked. Other volunteers slowly lowered the lever, creating what’s called an eccentric contraction. You get an eccentric contraction when you lengthen a muscle, such as lowering a barbell during a curl, and it tends to be more exhausting. A third group of volunteers held the weight of the lever steady in the air, battling gravity, in a kind of contraction where the muscle doesn’t change length at all.
And each of the participants did their biceps exercise for a total of three seconds.
That was it; that was their entire daily training. They repeated this extraordinarily short exercise routine once a day, five times a week, for a month, for a total of 60 seconds of strength training. They have not exercised otherwise.
At the end of the month, the researchers retested everyone’s arm strength.
Those three-second sessions had changed people’s biceps. The groups that lifted or held the weights were between 6 and 7 percent stronger. But those who did eccentric contractions and lowered the lever like you might take a barbell off your shoulder showed significantly greater gains. Their biceps muscles were nearly 12 percent stronger overall.
These improvements may sound small, but they would make biological sense, especially for people new to strength training, said Ken Nosaka, a professor of exercise and sports science at Edith Cowan University in Joondalup, Australia, who contributed to the study. “A lot of people don’t do resistance training,” and starting with very short workouts can be an effective way for them to start a strength-training regimen, said Dr. nosaka. “Every muscle contraction counts” and helps build strength, assuming you lift a weight close to the maximum you can handle and take at least three seconds, he said.