The super-slow approach
Building muscle requires you to put tension on the muscle, making the fibers contract and getting them to fire repeatedly while under stress. When you work muscles in slow motion, you activate more muscle fibers and keep them firing for longer in order to sustain the slow pace of lifting. "You will put much more consistent tension on the muscles when you lift slowly," says Westcott. And that may be the technique's biggest advantage.

"In our studies, we had people do 14-second repetitions," says Westcott (taking 10 seconds to lift the weight and four seconds to lower it). Westcott recommends doing sets of just four to six repetitions when using the super-slow technique. "A set will take about the same time as a conventional set in which you do more reps but at a faster pace," he says. When you first try out the technique, you might have to drop the amount of weight you lift until you get used to the slow-motion movement. But you should be able to quickly build back up to whatever weight you were previously lifting.

The biggest problem with super-slow training is that it's really hard -- both mentally and physically. "Out of 150 people in our studies, only two said they would continue training this way," says Westcott. "It's a tough way to train, and people didn't enjoy it." Working with a trainer can help keep you moving in slow motion (and there are even super-slow gyms that focus exclusively on training at a snail's pace), but it may be hard to motivate yourself to do it several times a week on your own.

The conventional approach
When you lift weights properly in the traditional manner, you still don't want to move too quickly. As a general rule, lift for two seconds and pause briefly before lowering for four seconds. You should be able to do 10 to 12 repetitions at this pace before the muscles fatigue. The biggest downside of faster-paced weight lifting is that you end up using momentum to help move the weights. "Momentum isn't a good thing for building strength," says Westcott, "because it doesn't place as much consistent tension on the muscle." The faster you move, the more you're relying on the speed of the weights already in motion to do the exercise, instead of your muscles.

The ideal lifting schedule
Whether you lift in slow motion or slightly faster, you don't want to work those muscles more than a few days a week. "Muscles that have been put under stress need rest time to repair and rebuild," says Westcott. So plan for two or three weight-training sessions per week, spaced out so that you have a couple of recovery days in between.

In Westcott's two studies of super-slow versus conventional weight training, the slowpokes did gain more muscle strength. But since he also found that most people won't stick with the program, he has another suggestion for harnessing the strengthening powers of the super-slow approach. "Use it as a plateau-breaking technique," he suggests. When you stop seeing improvements and need to shake up your routine, try switching to super-slow lifting for four weeks. "The high intensity will get you past the plateau, and then you can return to your regular routine," says Westcott.