By the end of eight weeks, both groups had made significant health gains while showing little statistical variance between those gains. In other words, the women who exercised two days a week reaped virtually the same benefits as those who worked out three times a week. Additionally, both groups increased their flexibility, with the 2x group reaching an average of 1.7 inches farther and the 3x subjects reaching 1.2 inches farther. Both groups significantly improved their strength, with the 2x subjects showing somewhat slower results on only three exercises - the standing lat pull, the triceps extension, and the leg press. Unfortunately, building stronger muscles did not result in either group losing weight.
Muscle weighs more than fat, but it's also more efficient at burning calories.
DiBrezzo believes the duration of the study limited weight loss results. After only eight weeks, subjects were already noticing that their clothes fit more loosely, she said. Had the experiment gone on longer, the women would have continued to firm up and would have shed more pounds. Weight training leads to greater muscle fitness, which in turn boosts metabolism. But DiBrezzo cautions that this type of exercise represents only one facet of a complete fitness regimen.