Several recent studies found that intense weight training plays an important role in weight control, because it causes a prolonged increase in post-exercise oxygen consumption and metabolic rate. Is a heavy or light load best for promoting additional caloric expenditure?
A University of Southern Maine study, led by Christopher Scott, found that oxygen consumption was higher during exercise while doing a single set to exhaustion using light loads ranging from 37 to 56 percent of maximum load, compared to an exhaustive set using 70 to 90 load of maximum load. However, post-exercise oxygen consumption (i.e., metabolic rate) was similar following the two types of training.
Maximal weight training, using heavy or light loads, causes prolonged increases in metabolic rate, which might help people preserve muscle mass and lose fat during weight loss. (Journal Strength Conditioning Research, 25: 903-908)