In the fitness world, there has long been a debate on whether the more effective approach to building muscle is heavy weights for low reps, or light weights for high reps. Now, a new McMaster University study indicates that lifting lighter weights is at least as effective for gaining strength as the heavy weight routine.

Even fitness trainers can hold certain misconceptions about light vs. heavy weight lifting in workouts. One idea is that heavy weight workouts are for muscle building while light weights are used for toning muscular regions - but there is no basis for such thinking.

Another common misconception is, while lifting light weights for high reps is a good routine for increasing muscle endurance, you need to lift heavier weights to build up muscle mass in an effective fashion. If the new research is correct, then this is simply not true. Science still has a lot to learn - and a lot to teach us - about the mechanisms of building muscle across multiple fitness approaches.

Psychology Today reports that the McMaster University researchers looked at two groups of men, both made up of experienced weight lifters. All of the men were required to keep to a 12-week whole-body exercise regimen.

The first group was instructed to lift light weights (up to 50 per cent of maximum strength) for 20 to 25 repetitions per set. The second group was tasked with using heavy weights (up to 90 per cent of maximum strength) for eight to 12 reps per set. In both groups, the men had to lift to the point of fatigue.

Both groups of men ended up exhibiting practically the same amount of development in muscle mass and muscle fiber size. The researchers concluded that the crucial aspect was lifting to the point of exhaustion.

"Fatigue is the great equalizer here," said the study's lead author Stuart Phillips in News Medical. "Lift to the point of exhaustion and it doesn't matter whether the weights are heavy or light."