How Many Sets and Reps should I do? Part I – Time under tension – TEMPO

This is goal specific but the real question to answer is what is the goal? Do you want to gain strength? Do you want to gain size? Do you want increase definition/tone? No matter how you answer the goal question the “base” of the answer has to do with “time under tension”. Time under tension refers to the amount of time you spend doing a set of a particular exercise. Once you’ve answered the goal question you decide on how best to address the other variables of intensity, load, volume, tempo, rest:work ratio, along with sets and reps, and finally training frequency throughout the week and given training cycle.


A slower repetition means that your body is experiencing longer “time under tension” for most people this is desirable. Why? Because when your body is working it is building muscle, adding the appropriate and aesthetically desirable amount of lean muscle is the best way to lose body fat…all the science supports this!!! So when you hear or read that you must perform fewer sets or more sets or more repetitions be sure you’re clearly understanding what you’re hearing or reading. Why is the set or rep range being suggested? What is the desired goal? How fast or slow is each repetition being performed? Speed of repetition is referred to as tempo. The tempo of a rep is critical because this is how the “time under tension” is realized. 

Think about it for a second if the speed/tempo for an exercise the same for a person doing 10 reps as it is for another person doing 25 reps—who is experiencing greater “time under tension”? The person doing 25 reps right? So the most important variable is to appreciate and understand is the “time under tension”.


There are many ways to experiment with the tempo for reps. The speed of the decent of a movement, the transition phase and the speed used for the creation of force against the resistance. The force and control used during the decent of a movement can be referred to as the eccentric phase of a contraction. For a very simple reference think about a push-up. Starting with the up position with the arms fully extended begin lowering towards the ground against gravity while controlling your body and the speed of movement—for some muscles of the upper body this would be eccentric strength training. The strength and control used to create force to move a resistance can be referred to as the concentric phase of a contraction. Using the push-up example again now envision that you’re at or near the floor having just completed the lowering phase as you create force and push your body away from the floor you’re now performing the concentric phase of this exercise. Important side note the greatest strength gains and the greatest results in injury prevention are realized with ECCENTRIC training.

Back to the speed of movement now that you have perspective on the phase for a contraction and a brief understanding of the results to be gained in the eccentric phase. An excellent tempo for a beginner is to use a 4 count during the eccentric, then a 2 count pause before moving the resistance back to the starting position, finally use a 2 count to return to the starting position. So there’s a 4 count eccentric phase, a 2 count isometric phase and a 2 count concentric phase. I know I didn’t discuss the isometric phase. The isometric phase would be a phase where the force you create equals the resistance without moving the resistance. An intermediate or advanced person with no limitations, injuries and with significant muscle size or tone could manipulate these tempo suggestions to break through a plateau—you should not experiment too early in your training with tempo until you’ve made and can SEE real results!!! Don’t think you’ve made progress—KNOW IT!!! Measure body fat and girth to get started and then periodically. Guessing is counterproductive and discouraging.

Digesting and understanding Tempo 

Identify your desired goal. Be clear on “time under tension”. Think of the movements you think you want to do and understand what these movements would develop. Then decide on how much “time under tension” you think you should spend given your current fitness and stick to it for a period of 4 weeks. To know if this effort was successful measure your girth and body fat then remeasure at the end of 4 weeks. Be sure you align your expectations with your commitment level as it relates to exercise, nutrition, hydration, sleep, dietary needs for desired change, as well as the influence of things like stress, alcohol, smoking and medications.