Tired of waiting around in the gym for the right weights to be free? New research form the US means you can make gym queues like this a thing of the past, as it proves that you can build muscle just as fast using lighter weights. Traditional exercise wisdom says that the quickest way to build big muscles is to lift as heavy as possible. However, the new study shows you can get equally impressive results from going lighter but performing more repetitions. The only condition is that you must do all your sets to failure. So, next time your preferred dumbbells are taken, just switch down and up your reps. You'll be out of the gym that much quicker and still see the growth you're looking for.