When you’re new to the bodybuilding arena, it can be tempting to lift all the weight, all at once. When your form is all over the place, your risk for injury increases and your muscle gains suffer in the process. Slowing down the tempo, or how quickly you lift a weight, increases muscle tension. Increasing time a muscle is under tension is key to developing muscle size.
Breaking Down Time Under Tension
Time under tension refers to the time a muscle is under tension in a set. A slower tempo results in more time under tension. Tension stimulates the mechanisms required to repair the micro tears that occurred during exercise, bringing in nutrients to lay down new muscle cells (a.k.a. size). There are 3 ways to break up a lift when it comes to tempo training. There’s the eccentric contraction, or lowering the weight to resting. During the eccentric portion of a rep, the muscle is lengthening and storing potential energy for use during the concentric phase. The concentric contraction is raising the weight, shortening the muscle. The contracted, isometric position is holding the weight at the top of the movement. The time is broken up into seconds. For example, a typical biceps curl would have a 2 second concentric contraction to power up to the top, a 1 second isometric pause at the top and a 2 second eccentric lowering to rest at the bottom. So the tempo prescription is a 2-1-2 (concentric-isometric-eccentric).
How Slow Should You Go?
If you are just starting out with weight training, slower is better. Taking your time with lower weight will help ensure that you are activating muscle fibers appropriately and laying down a solid foundation for growth. Start with a 3:1:2 or 4:2:3 eccentric-isometric-concentric tempo. If you are used to lifting a weight as fast as possible, then you may need to lower the weight and count out loud until you adjust to the speed. Once you have nailed this tempo for a few weeks, you are ready to increase the speed. For muscle hypertrophy (or gaining size), aim for a temp of 1-2 second eccentric phase, a 1 second hold at the isometric portion, and a 1-2 second during the concentric phase.
As for sets and reps, 3-4 sets of 8-12 reps is generally recommended for muscle growth. Note that the last few reps should be difficult, but your form should not suffer based on the weight. Again, with tempo training you may need to cut back on the weight you’ve been using. Slowing down the tempo may be challenging, but it is worth it in the long run!
Megan is a Registered Dietitian and Personal Trainer in the Baltimore area. Her mission is to connect people with nutrition and fitness information that makes sense – information that is reliable, realistic, and fun.