Bicep curls aren't the only way to strengthen your arm muscles.
A recent study demonstrates an effective alternative technique that achieves results after just three seconds of working out three times a week.
That's just 36 seconds of weight work over the course of a month, according to a team from Edith Cowan University in Australia in collaboration with institutions in Japan.
The study is small, but it supports previous findings that suggest eccentric, muscle-lengthening exercises can strengthen bands of fibrous tissue more efficiently than concentric, muscle-shortening actions.
Past research has found a small amount of resistance training that focusses on lengthening muscles is a far more effective technique.
In other words, lifting a heavy dumbbell from the waist to the chest may not be as useful for muscle conditioning as the reverse movement. Sure, it burns more calories, but the alternative stiffens the muscle more and also induces changes in the brain associated with greater muscle responsiveness.
In the current experiment, 26 young, healthy adults were split into two groups.
One group performed three-second workouts of bicep extensions twice a week. The other group performed the same exercises three times a week.
After four weeks, researchers compared the forces delivered by their elbow flexors and the muscle thickness of their biceps brachii and brachialis.
These results were then compared to a previous study by some of the same authors, which had participants do similar exercises five days a week.
In this past study, 3-second workouts that lengthened bicep muscles produced the best results compared to those that shortened them.
After a minute of accumulative exercise, spread across four weeks, participants in the eccentric training group improved their muscle strength by 11.5 percent.
"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," said exercise and sports scientist Ken Kazunori Nosaka in 2022.
To be clear, these short workouts probably don't improve cardiovascular fitness, just muscle strength.
Nevertheless, the current study suggests that these three-second bouts of eccentric bicep contractions can achieve impressive physical results with as few as three workouts a week.
After four weeks, participants who worked out three times a week saw, on average, a 2.5 percent increase in concentric strength and a 3.9 percent increase in eccentric strength.
Those who worked out twice a week showed no significant improvements.
"Our previous work has shown regular, shorter exercise is more beneficial than a one or two big training sessions in a week," explains Nosaka.
"Now, we have a clearer idea of where the tipping point is where you start to see meaningful benefits from such a minimal exercise. These new results suggest at least three days a week are required, at least for the single three-second eccentric contraction training."
Nosaka and his colleagues suspect that these super-short workouts are more effective than a big workout because they allow the muscle to recover more easily.
The rest between exercises is close to 28,800 times more than the actual exercise time.
In a study from 2017, this down-time was linked to a 'silent period' in the motor cortex, and initial results suggest this silence may be involved in increasing muscle strength.
More research needs to be done to suss out the details, but it seems possible that to a certain extent, the frequency of a workout matters more than the actual duration of it.
"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," says Nosaka.
The study was published in the European Journal of Applied Physiology.