Contrary to belief that one needs to lift heavy weights to build muscle size, a new study has shown that muscle building can be also be achieved by using lighter weights.
The secret, researchers at McMaster University say, is to pump iron until you reach muscle fatigue.
"Rather than grunting and straining to lift heavy weights, you can grab something much lighter but you have to lift it until you can't lift it anymore," says Stuart Phillips, associate professor of kinesiology at McMaster University.
"We're convinced that growing muscle means stimulaing your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles," Phillips added.
Phillips praised lead author and senior Ph.D. student Nicholas Burd for masterminding the project that showed it's really not the weight that you lift but the fact that you get muscular fatigue that's the critical point in building muscle.
The study used lightweights that represented a percentage of what the subjects could lift. The heavier weights were set to 90 percent of a person's best lift and the lightweights at a mere 30 percent of what people could lift.
"It's a very light weight," says Phillips noting that the 90-80 percent range is usually something people can lift from 5-10 times before fatigue sets in. At 30 percent, Burd reported that subjects could lift that weight at least 24 times before they felt fatigue.
"We're excited to see where this new paradigm will lead," says Phillips, adding that these new data have practical significance for gym enthusiasts but more importantly for people with compromised skeletal muscle mass, such as the elderly, patients with cancer, or those who are recovering from trauma, surgery or even stroke.
The findings are published in PLoS ONE.