It's a long-standing belief that lifting heavy weights for fewer repetitions is the best way to increase muscle and strength, but new research released this week suggests that lifting lighter weights for more repetitions could be just as effective.
Weightlifting is already known for its many health benefits including increased weight loss, improving osteoporosis, aiding sleep, and even boosting cognitive function. This new research, carried out by a team from McMaster University, Canada, is now the latest in a series of studies that started in 2010 and contradicts the idea that heavy weights and lower reps is the best way to promote the other health benefits of weightlifting, increased muscle and strength.
For the study researchers recruited two groups of all male participants for a 12-week period, who were also all experienced weight lifters. One group lifted lighter weights (up to 50 percent of maximum strength) for 20 to 25 repetitions, while the other group lifted heavier weights (up to 90 percent of maximum strength) for eight to 12 repetitions.
Both groups worked the whole body and lifted to the point of failure. The team then analysed muscle and blood samples and found that despite the differences between the groups in both weight and repetitions, the increase in muscle mass and muscle fiber size — a key measure of strength — were virtually identical.
Senior author of the study Stuart Phillips explained the results saying, "Fatigue is the great equalizer here. Lift to the point of exhaustion and it doesn't matter whether the weights are heavy or light."
Blasting testosterone myths
The results also go against another popular belief that testosterone or growth hormone are responsible for increases in strength and muscle, with the results showing that this was not the case in either of the groups. "It's a complete falsehood that the short-lived rise in testosterone or growth hormone is a driver of muscle growth," commented one of the study's co-authors Rob Morton, "It's just time to end that kind of thinking."
And even more good news, Phillips also added that this alternative method of weight lifting, while unlikely to be adopted by elite athletes, is an effective way for regular gym goers to improve health, increase strength, and put on muscle, and could even encourage those who have been intimidated by strength training and its heavy weights to venture into the weights room as part of their next workout.
"For the 'mere mortal' who wants to get stronger, we've shown that you can take a break from lifting heavy weights and not compromise any gains," says Phillips. "It's also a new choice which could appeal to the masses and get people to take up something they should be doing for their health."
The findings are published online in the Journal of Applied Physiology.