Light weights, many repetitions effective at building muscle mass.

New research is challenging traditional workout wisdom which says that heavy weight lifting is the best way to build muscle.
In the latest results from a 16-year study by McMaster University in Hamilton, Ontario, lifting lighter weights many times was found to be as efficient as lifting heavy weights for fewer repetitions.

In the study, two groups of experienced male weight lifters followed a 12-week, whole-body protocol. One group lifted lighter weights (≥50 per cent of maximum strength) for sets of 20-25 repetitions. The other group lifted heavier weights (≥90 per cent of maximum strength) for 8-12 repetitions. Both groups lifted to the point of failure. Gains in muscle mass and muscle fiber size were virtually identical in both groups.

It appears that fatigue is the great equalizer. At the point of fatigue, both groups would have been trying to maximally activate their muscle fibers to generate force. Lift to the point of exhaustion and it doesn’t matter whether the weights are heavy or light.

The findings are published online in the Journal of Applied Physiology:http://jap.physiology.org/content/jap/121/1/129.full.pdf