Could three seconds a day of resistance exercise really increase muscular strength?
That question was at the heart of a small-scale new study of almost comically brief weight training. In the study, men and women who contracted their arm muscles as hard as possible for a total of three seconds a day increased their biceps strength by as much as 12 percent after a month.
The findings add to mounting evidence that even tiny amounts of exercise — provided they are intense enough — can aid health. I have written about the unique ways in which our muscles, hearts, lungs and other body parts respond to four seconds of strenuous biking, for instance, or 10 seconds of all-out sprinting, and how such super-short workouts can trigger the biological responses that lead to better fitness.
But almost all of this research focused on aerobic exercise and usually involved interval training, a workout in which spurts of hard, fast exertion are repeated and interspersed with rest. Far less research has delved into super-brief weight training or whether a single, eyeblink-length session of intense resistance exercise might build strength or just waste valuable seconds of our lives.
So, for the new study, which was published in February in the Scandinavian Journal of Medicine & Science in Sports, scientists led by Masatoshi Nakamura at the Niigata University of Health and Welfare in Niigata, Japan, asked 39 sedentary but otherwise healthy college students to do three seconds of weight training every day. They also recruited an additional 10 students who would not work out to serve as a control group.
The exercising volunteers gathered during the workweek at the lab for strength testing and weight lifting, of a kind. 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 precisely control people’s movements and effort.