We've gone over this before in our post on low and high-rep training, but it bears repeating: Whether you lift light or ultra-heavy weights, your muscles can still grow, provided you push yourself to the point of being unable to physically lift an additional rep. In the end, it's all about intensity. Images by WODShop and U.S. Naval Forces Central Command/U.S. Fifth Fleet.
In a recent study published in the Journal of Applied Physiology, Canadian researchers took 49 men who'd been weight training for the past two years. Already there are two key contributions by this study: It involves a larger sample size than most similar studies and subjects who would not just experience a bunch of newbie gains to muddy results.
Half of the subjects were placed into a high-rep group (20 to 25 reps); the other in a lower rep group (eight to 12 reps). Each group trained four days a week for 12 weeks, where the overall amount of "work" they performed were similar. There also weren't any significant differences between their diets. To really ensure that subjects lifted with true intensity (to "failure", as it's called), the researchers trained each subject individually and generally made sure the subjects really had nothing left in them by the end of a set.
At the end of the 12 weeks, researchers tested the subjects' thigh muscle and found that both groups built similar amounts of muscle. They also had similar increases in strength, a finding that challenges the idea that high-rep training doesn't increase strength as effectively. Strength is a product of having both muscle and a nervous system that's used to lifting a certain amount of weight. The paper explains that increasing your maximal strength is possible with high-rep training, as long as you also periodically lift with really heavy weight.
And finally, one other interesting tidbit that came out of this study: Growth hormone and testosterone, which are thought to be big drivers of muscle gain, did not affect the results.
So what's the message here? One of the study's authors, Stuart Phillips, a professor in the Department of Kinesiology at McMaster University says:
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. 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.
If you're going to lift with the intention to get big and strong — whether it's for 30 reps or for five reps — make sure that you work really, really hard.