There is a general belief that to build your muscles, you ought to lift heavy weights. However, a 2010 study found that building muscle depends on achieving muscle fatigue and not on pumping heavy weights as previously believed.
The study conducted at McMaster University has shown that a similar degree of muscle building can be achieved by using lighter weights. The secret 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 stimulating your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles.”