Longer is not a result
A push-up can take two seconds or six. The second version keeps you moving for longer, but the stopwatch cannot tell you which produces more strength or muscle growth. Slower repetitions can be useful; making every repetition as slow as possible is a different claim.
First, name what you are changing. A slower lowering phase, a pause at the bottom, and a slower push back up are three separate choices. “Slow reps” hides those details. So does a total set time that includes pauses between repetitions.
Slow training can work
In a 12-week study, Tanimoto and Ishii assigned 24 young, untrained men to three knee-extension programs. Both light-load training with slow, continuous tension and heavier training at a normal speed increased measured muscle size and isometric strength. The light-load, normal-speed group did not show those significant changes. [1]
This was not speed in isolation: the protocols also differed in relaxation between repetitions and how demanding the sets were. The slow and heavy groups trained to exhaustion; the light, normal-speed group matched the slow group’s load and repetition count. The finding does not prove that slower is always better, or supply an ideal push-up tempo.
Your goal changes the question
A 2024 home-training study followed 32 men aged 65–88 across fast, slow, and no-exercise groups. After eight weeks, both training groups improved peak muscle power. [2] Power concerns producing work quickly; it is not the same outcome as muscle size. These results do not establish one winning speed for every person or exercise.
The studies involved different ages, exercises, and protocols. Neither lets us turn “this feels harder” into “this will produce better results.” Nor are they instructions to rush an unfamiliar movement or copy a research program.
Choose your pace for a reason
Our practical suggestion: before changing the pace, finish the sentence “I am slowing this part down because…” You might want to follow a tempo already specified in your plan or pay closer attention to one phase. That is a reason for the choice, not proof of extra muscle growth.
If your plan specifies a tempo, check which phase each number describes. If it does not, you do not need to invent a complicated code. Plain words such as “deliberately slower lowering” are enough to record a change. Keep variation, movement range, rests, and effort in view too.
At your next session, decide whether you are repeating the same task or trying a different one. Record a deliberate pace change and compare it with similar sessions. You can choose slow repetitions without making the longest possible set your target.