Workout Extender #4:
Change Your Tempo
It's easy to race through a set. If the weight is heavy, you get psyched and want to punch it through the roof on each rep. If the weight is light, you get into a groove and "pump out" your reps like you're dancing to a club beat. While both methods do allow you to move the weight from point A to point B, neither fully stimulates your muscles, because you're using momentum. To promote the most muscle and strength, you need to keep tension on the working muscles and ensure that as many muscle fibers as possible are recruited.
Studies have shown that sets lasting between 40 and 70 seconds are best for achieving muscle growth. Shorter sets imply heavier weights, so those are best for pure strength. Longer sets, naturally, would benefit endurance goals. In general, the portion of the lift in which your muscles shorten (usually the "up" part, such as pushing the barbell off your chest on a bench press, or raising the barbell on a curl) should be done fast to maximize the activation of your strongest muscle fibers. The portion of the lift in which your muscles stretch (the "down" part) should be done more slowly, as the muscle is actually stronger in this phase than in the upward one. But exercise scientists have discovered that regimenting a rep further can enhance muscle activation even more.
The technique is called "tempo," and it's usually represented as a three-digit number. The first digit is the number of seconds you should take to perform the lowering portion of the lift. The middle digit is how long you should pause in that bottom position (when the muscles are under the most tension), and the third digit indicates how long you should take to lift the weight to the "up" position. Occasionally, you'll see tempos with an "X" in place of a digit, which means you should perform that portion of the lift with explosive speed. Furthermore, a "0" means to move immediately to the instructions of the next digit. So, for example, a tempo of 311 on a bench press would mean to take three seconds to lower the bar to your chest, one second to hold it there, and another second to press it back up. Tempo may sound tedious, but it's a great way to keep your form in check, especially when you're performing a number of reps (when your form is most susceptible to falling apart).