Upending everything you thought you knew about gaining muscle size and strength, a new study is saying that the key to success is muscle fatigue – not how heavy your weights are.
The study, published last month in the Journal of Applied Physiology followed 49 young men who had been strength training for at least a couple years. Separated into 2 groups, the men underwent 12-week whole body regimens. One group stuck with the standard resistance-training program: 75-90% of their max weight for eight to 12 reps per set, until they experienced muscle fatigue. The second group used lighter weights, lifting 30-50% of their max weight for 20 to 25 reps per set, until their muscles exhausted. The groups completed three sets of each exercise four times per week.
After all the testing was done, no significant difference was found between the strength or muscle gain of the two groups. Conclusion: the key is muscle fatigue, or repeating a lift until you are unable to complete another rep, not how heavy the weights were.
For anyone who has been intimidated by heavy lifting, or physically unable to, these findings will be welcome news.
Matthew Miller, a Denver-based personal trainer and coach at Fitwall, said he already recommends lighter lifting to select people, such as those working around injuries or if aesthetics is the only goal. For them, he uses super slow reps with lighter weights.
“This might be the best of both worlds,” he said. “It’s challenging and, from what I read, it can build strength and size, while also being very safe and convenient. I have personally incorporated this super slow work, especially when I don’t have access to a lot of weight.”