1. Intent – A movement, a squat for example, is not the sole focus in a general prescription. The intent of a training session is going to be absolute strength of a squatting movement. So if we program 5×5 squats and someone goes very fast then they have squatted but have they reached the desired stimulus of increasing absolute strength? No. So if we write in the tempo of 31X1, this requires them to move at a specific speed and then hopefully respond the desired stimulus.
2. Repetition/volume – From week to week if someone is not following the correct tempo then they will be missing out on the periodization of change in tempo. If they do 41X1 one week then 11X1 the next when they were supposed to do the same for both they wont progress in the same way. If we do 20 reps @ 41X1 that is 80 total seconds of eccentric work. Thats an easy way to track total volume and that is an improtant reason to try to keep people on tempo.
3. Stimulus – 12-15 reps does not equate to hypertrophy, 16-20 does not equate to endurance, and 3-5 does not equate to strength. There are no absolutes in increasing the ability of a muscle or group of muscles to do work, but there are general ways to improve those things. Time under tension will determine the stimulus. I can do 12 reps of curls at 2 different tempos and make the difference of 60 seconds of holding on to those DBs.
Here are some direct improvements or main reasons why tempo can help someone:
-Develop motor control and proper movement mechanics
-Recruit muscle fibers
-Create efficiency in movements
-Make a movement more metabolic
-To increase force development
-To increase muscle size, strength and markers of performance
-To create adaptations and recruiting in higher threshold motor units
-To create hypertrophy
The main reason being increasing motor control! 100% of the gym can improve on this and most need to improve on motor control just to be safe in some of the movements we do. Always encourage others to be strict on tempo and there is always a reason more than we want to make it more complicated and difficult.