The findings of a new study from the McMaster University have challenged perhaps the only thing we hold sacred in the art of building muscle: the combination of weight and reps. Traditional bodybuilding wisdom will tell you that muscle growth is the result of lifting heavy weights for fewer repetitions, while lifting lighter weights for many repetitions is practically a waste of your time.
But the latest in a series of studies that began in 2010 found evidence that supports an opposing view on the subject, claiming that it doesn’t really matter whether you lift heavy or light and whether you do it in the low or high rep range – both combinations have the same potential to stimulate gains in terms of strength and mass.
According to Stuart Phillips, senior author on the study and professor in the Department of Kinesiology, “Fatigue is the great equalizer here. Lift to the point of exhaustion and it doesn’t matter whether the weights are heavy or light.” The study, published online in the Journal of Applied Physiology, used two groups of seasoned male weight lifters who followed a 12-week training protocol.
Both groups lifted to the point of failure, but the first group lifted lighter weights (up to 50% of maximum strength) for 20-25 repetitions per set, while the second group lifted heavier weights (up to 90% of maximum strength) for 8-12 repetitions per set.
Analyzing muscle and blood samples from the lifters, researchers found that the gains in muscle fiber size and mass in the two groups were almost identical. Even though popular gym dogma holds that heavy weights are the key to increasing muscle size, these findings suggest that you can achieve the same degree of muscle development by using lighter weights, as long as you pump iron until reaching absolute muscle failure.
“At the point of fatigue, both groups would have been trying to maximally activate their muscle fibers to generate force,” explains Phillips. “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,” he adds. “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 second most important finding of the study was that the common belief that the levels of testosterone and growth hormone are not the major drivers of muscle growth is an unfounded misconception. However, these results need to be further investigated and more work needs to be done on this subject before coming to an ultimate conclusion.
So what does this study really teach us?
First of all, as it turns out, building muscle is not so much about the amount of weight that you lift as it is about reaching the point of muscular fatigue, so you are free to drop the heavy weights once in a while without worrying that your gains will be at risk. However, the essential way to maximally stimulate the post-training muscle growth response is by lifting until failure.
That being said, it doesn’t matter how failure is reached, i.e. by using heavy weight for a few reps or lighter weight for many reps. All of this doesn’t mean that you should lift every set until failure – that’s a good recipe for overtraining which will set you back instead of propel you forward. Just keep in mind that the best gains come from lifting until additional reps become extremely difficult to perform, so for optimal results, stop stressing about the amount of weight you should lift and strive to reach maximum or near-maximum muscular fatigue as often as possible.
What do you think about the results from the study ?