Slow Reps vs. Quick Reps? The answer depends on whether you are looking for increased strength or added muscle size. Studies have shown that slightly slower reps - on both the concentric and eccentric phases - yield greater muscle size - whereas faster explosive reps can recruit more fast twitch fibers, leading to increased strength.
I like to start each rep slow and controlled, to ensure I’m isolating the target muscle and not recruiting other muscle groups, then explode upward. At the top I take a slight pause to squeeze and then do a slower controlled eccentric contraction. Each complete rep is about 4 seconds as opposed to 2 seconds on a fast rep or 6 seconds on a slow rep. This is one easy way to combine both size and strength benefits.