Until recently, conventional wisdom on weight training encouraged people to increase the size of their weights as they became stronger. Logically, it makes sense, but a recently released study is challenging that notion. A lab at McMaster University in Canada has been studying the effects of different types of weight training since 2010, particularly the difference between lifting heavy and lighter weights.
In a study published this month, the lab found that people who lift lighter weights can, in fact, build just as much muscle as those who lift heavier weights over time. The study tracked 49 men who already had experience weight training for a year. Half the group was assigned to lift heavier weights, ones that would cause them to fatigue after performing 10 reps. The other group was assigned lighter weights which would cause fatigue around 25 reps. The training sessions were tracked and administered four times a week for 12 weeks. Surprisingly, the resulting gains between the two groups were identical. Each set of men improved their strength regardless of the weights lifted.
Although the study only monitored men, the scientists have plans to test the same study on women. They hypothesized that it is muscle fatigue — not the actual size of the weight — which builds stronger muscles. While the team also didn't differentiate which exercise was ultimately more beneficial, Dr. Stuart Phillips, who led the study, told the New York Times that "some people will find it much easier or less intimidating" to lift lighter weights. So next time you hit the gym on your quest for sculpted arms, remember you can use lighter weights with more reps and still achieve the same results.