The best way to build muscle may not be lifting the heaviest weights

Fitness weight lifting weightlifting workout gym exercise woman

Whether you want to tone up or slim down, you’ve likely added some kind of weight training into your fitness routine at some point.

Most people think the quickest way to build muscle is to use the heaviest weights you can manage. This approach usually means you won’t do very many repetitions (“reps”), since you’ll get exhausted pretty quickly.

Aside from making you vulnerable to injury, that method may not be the best way to tone up. Instead, doing the same exercise with less weight for more reps could give you the same results.

Mike Robertson, a certified strength and conditioning specialist with a master’s degree in sports biomechanics from Ball State University’s Human Performance Lab, supports that approach.

“If you train with high reps, your goal is to build a bigger muscle,” Robertson told

Fitness research backs up the practice as well.

Weight lifting

For a recent study published in the Journal of Applied Physiology, researchers took 49 young men (no women were included in the study), all of whom had been doing some kind of weight training for at least a year, and split them into two groups. All the men worked out four times each week for three months. The first group stuck with their standard weight-training regimen involving heavy weights and a low number of reps. Someone in this group, for example, might do arm curls with a 20-pound weight and repeat the exercise eight or 12 times. People in the second group, on the other hand, were instructed to reduce their weights and increase their number of reps. So instead of eight reps with a 20-pound dumbbell, someone in this group might do 20 or 25 reps with an 8-pound weight.

The researchers measured the muscle tone of people in each group before and after the three-month workout plan. Surprisingly, they found no significant differences between the two groups — they’d all built bigger, stronger muscles.

“Fatigue is the great equaliser here,” Dr. Stuart Phillips, a kinesiology professor at McMaster University and the lead author on the study, wrote in a press release. “Lift to the point of exhaustion and it doesn’t matter whether the weights are heavy or light.”

Still, Robertson recommends alternating between the two approaches so that your body doesn’t get accustomed to a routine. “High reps build muscle and connective tissue strength, and give your body respite from the grind of low-rep sets,” he says.

There’s a key takeaway here for anyone who has avoided a weight room because they don’t like the idea of pumping bulky iron: You may be able to get the same benefits with lighter weights. And you can always add new elements (or more weight) to your routine to keep things fresh.

NOW WATCH: 6 ‘healthy’ eating habits you are better off giving up