RoseTracker| Researchers at McMaster University say that you don’t need heavy weights to build muscle size. The same effect can be achieved using lighter weights in enough weights that muscle fatigue is reached. This state of muscle fatigue means that you’ve lifted the weight until you can’t lift it any more.
The heavier weights were set to 90% of a person’s best lift and the light weights at a mere 30% of what people could lift. “It’s a very light weight,” says Stuart Phillips, associate professor of kinesiology at McMaster University. The 90-80% range is usually something people can lift from 5-10 times before fatigue sets in. At 30%, subjects could lift that weight at least 24 times before they felt fatigue.
These results are most encouraging for people with lighter skeletal mass or people in recovery from injury and disease. via Science Daily