The three main mechanisms used to drive muscle growth in the gym are load, volume, and time under tension. To stimulate muscle growth you want to utilize all three types of training to maximize your results in the gym. Lifting heavier weights at near maximal loads (think 1-5 reps per set) not only helps you get stronger, but also creates new muscle tissue. Lifting lighter weights for higher volume (think 8+ reps per set) to failure also drives new muscle growth. While lifting heavy and high volume often get a lot of love in the CrossFit world, time under tension is often overlooked or completely neglected.
Time under tension simply refers to the amount of time the muscle is under strain or tension in the duration of the set. While in many workouts, sheer volume can create a lot of time under tension, we can also attempt to create more time under tension by slowing a movement down. This is why we often perform slow negatives of pull ups, chin ups, and dips to help clients build muscle and strength in the upper body by spending more time with the biceps, triceps, and shoulder group under tension. These slower and more controlled repetitions are called tempo reps and there is a whole world of possibilities to make movements more challenging and stimulate more muscle growth through the use of tempo reps.
While most of us love lifting heavy weights, we also realize that we can’t lift heavy every day. Lifting heavy too frequently will certainly lead to injury, but by utilizing tempo reps with lighter loads, we can create more time under tension on the muscle and stimulate muscle growth without putting our bodies in a compromised position. Tempo reps also help strengthen smaller muscle groups, and tendons and ligaments that support our larger muscles, and help keep our bodies healthy and injury free. Not to mention slowing a movement down will create a greater mind muscle connection, and also improve movement patterns for beginners.
Tempo reps are best utilized in exercises for smaller muscle groups particularly in the upper body on most any pushing and pulling exercises. Add tempo reps in your next workout and aim to slow the movement down enough to make light weight feel heavy!