Lighter weights can be just as effective as heavy ones
By Gretchen Reynolds, New York Times
Upending conventions about how best to strength train, a new study finds that people who lift relatively light weights can build just as much strength and muscle size as those who grunt through sessions using much heftier weights — if they plan their workouts correctly.
Strength training has long been dominated by the idea that to develop a physique like that of Charles Atlas or even Zac Efron, we — and I include women here — must load our barbells or machines with almost as much weight as we can bear.
In traditional weight training programs, in fact, we are told to first find the heaviest amount of weight that we possibly can lift one time. This is our one-repetition maximum weight. We then use this to shape the rest of the program by lifting 80 to 90 percent of that amount eight to 10 times, until our affected arms or legs shake with fatigue.