No need to max out at the gym. A new study suggests that you can work out your muscles just as efficiently by lifting lighter weights more times than by lifting heavier weights fewer times.

"Fatigue is the great equalizer here," says Stuart Phillips, kinesiology professor and senior author of the study, in a statement released by McMaster University. "Lift to the point of exhaustion and it doesn't matter whether the weights are heavy or light."

The newresearch

Canadian researchers, primarily from McMaster University in Hamilton, Ontario, first published their findings in May in the Journal of Applied Physiology under the title, Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men.

“We report that the relative load lifted per repetition does not determine skeletal muscle hypertrophy or, for the most part, strength development,” the study states. “In line with our previous work, acute postexercise systemic hormonal changes were unrelated to strength and hypertrophic gains.”


The number of pounds you lift doesn’t decide how much muscle and strength you build. The second major finding is that testosterone and growth hormone don’t drive muscle growth.

A new way of working out?

This shatters widespread conventions for strength training. Traditional fitness wisdom dictates that building muscle most effectively requires lifting heavy weights.

Gym rats work with high weight and low repetition, striving to increase their “max” (the heaviest weight you can lift for one rep with proper technique).

You can find thousands and thousands of pages on the Internet and in magazines telling you how to push your workout to the limit and beyond.

This new research likely won’t have professional athletes furiously pumping light weights to train anytime soon. Testosterone- and growth hormone-boosting supplements are unlikely to see sales drop.

But as the research behind these findings develops, the way we look at fitness and muscle growth could drastically change.

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