Lighter weights just as effective as heavier weights to gain muscle, build strength

Lighter weights just as effective as heavier weights to gain muscle, build strength
Kevin Murphy, a kinesiology student and participant in the study, works out. Credit: McMaster University

New research from McMaster University is challenging traditional workout wisdom, suggesting that lifting lighter weights many times is as efficient as lifting heavy weights for fewer repetitions.

It is the latest in a series of studies that started in 2010, contradicting the decades-old message that the best way to build is to lift heavy weights.

"Fatigue is the great equalizer here," says Stuart Phillips, senior author on the study and professor in the Department of Kinesiology. "Lift to the point of exhaustion and it doesn't matter whether the weights are heavy or light."

Researchers recruited two groups of men for the study—all of them experienced weight lifters—who followed a 12-week, whole-body protocol. One group lifted lighter weights (up to 50 per cent of maximum strength) for sets ranging from 20 to 25 repetitions. The other group lifted heavier (up to 90 per cent of maximum strength) for eight to 12 repetitions. Both groups lifted to the point of failure.

Researchers analyzed muscle and blood samples and found gains in and muscle fibre size, a key measure of strength, were virtually identical.

"At the point of fatigue, both groups would have been trying to maximally activate their to generate force," says Phillips, who conducted the work with graduate students and co-authors Rob Morton and Sara Oikawa.

While researchers stress that elite athletes are unlikely to adopt this training regime, it is an effective way to get stronger, put on muscle and generally improve health.

"For the 'mere mortal' who wants to get stronger, we've shown that you can take a break from lifting 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."

Another key finding was that none of the strength or were related to testosterone or , which many believe are responsible for such gains.

"It's a complete falsehood that the short-lived rise in testosterone or growth hormone is a driver of muscle growth," says Morton. "It's just time to end that kind of thinking."

Researchers suggest, however, that more work remains to be done in this area, including what underlying mechanisms are at work and in what populations does this sort of program work.

The findings are published online in the Journal of Applied Physiology.


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More information: Robert W. Morton et al, Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men, Journal of Applied Physiology (2016). DOI: 10.1152/japplphysiol.00154.2016
Journal information: Journal of Applied Physiology

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Jul 12, 2016
I guess the use of the word "efficient" is subjective here, because for someone like me, a father who works out early in the morning and has to get my kids to school on time, efficient means getting the most out of my time. So if I can build the same amount of muscle in 12 heavy reps as 25 light reps, the heavy reps are MORE efficient. Also, I wonder if they looked at the neurological strength gains made with heavier weights, specifically muscle fiber recruitment.

Jul 13, 2016
I was thinking the same, but it is good to know when you have an injury and, at a guess, as a means to prevent the peaking in gain that comes from doing exactly the same thing too often.

Re recruitment, good point, but 3 months would be enough to see some or all of that effect. Recruitment starts after a week IIRC, and I know from a recent bout of autoimmune disease that recruitment + repair has a 3 - 12 months prognosis in adults. (Latest science is that adolescents seem to be able to shuffle their mitochondria far in nerve axions, likely because they still grow. While adults can't, our actins - the motor proteins that move organelles - are differently laid out, likely maximizing cell efficiency. That means adolescents have a leg up on repair + recruitment. 2 months minimum instead of 3.)

Jul 15, 2016
"challenging traditional workout wisdom"
How many decades it took to overturn the traditional wisdom! How many decades will it take to overturn global warming traditional wisdom?

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