Lighter Weights Also Help Muscle Growth

Exciting new research by Burd and colleagues shatters currently held beliefs about the type of resistance training required for muscle growth. Their article entitled “Bigger weights may not beget bigger muscles: evidence from acute muscle protein synthetic responses after resistance exercise” has been published in the journal Applied Physiology, Nutrition, and Metabolism. They found that performing repetitions until fatigue (an average of 24 repetitions) with 30% of one repetition maximum (1RM) was just as effective at eliciting muscle protein synthesis (MPS) as 5 repetitions with 90% 1RM! In fact, exercise performed at 30% 1RM produced longer lasting MPS.

The authors believe that maximal muscle fibre recruitment is fundamental in inducing MPS and that lifting light weights to failure causes the fibre activation required. In addition, low-intensity resistance exercise allows for a higher total number of repetitions and greater total exercise volume, which is important in sustaining the MPS response over time.

Burd et al. note that “skeletal muscle mass is a large contributor to daily energy expenditure and will assist in weight management. Additionally, skeletal muscle, because of its overall size, is the primary site of blood glucose disposal and thus will likely play a role in reducing the risk for the development of type II diabetes”.