Well that all depends on your goals. But most of us want to build as much muscle as possible right? The key to that is Time Under Tension (TUT). You may have heard this term in the past. It correlates to the amount of time that the muscle fibers are under tension. Varying your speed is important, and should be varied every 3-4 weeks. If you have heard the term “negatives” you will understand the concept of TUT and what it is trying to achieve.
Research has shown that the time that the muscle is under tension is crucial to gaining mass. You will want to extend the length of the rep itself, meaning extend the time the muscle is under tension for that particular exercise. So for a barbell bicep curl that would normally take you 1 second to complete a rep, extend that period to 4 seconds on the downswing. Ensure you are using heavy weight, something you can perform a maximum of 8 reps with. I wont get into muscle fibers themselves, but you want to activate the fast twitch (high threshold) muscle fibers, which stimulate muscle growth. Slow twitch (low threshold) fibers are fibers that are used for every day movements such as steering your car. So if you are using light weight, you will not be activating these slow twitch fibers that are needed to see GAINS.
You will want to extend the length of the entire set as well. So if it normally takes you 20-30 seconds to complete a set of squats, push that for a full minute with negatives incorporated (coming down slow). This will maximize muscle hypertrophy (enlargement of the muscle).
Coming back to the movement itself, performing a negative with the weight, meaning coming down slow with it instead of letting gravity take hold. Using that resistance will tear at the muscle and allow for more growth. The other part of the movement you want to incorporate is a faster tempo. So an explosive movement of the weight from initial lift to full extension, then a negative on the downswing.
Looking at the physiques of power lifters they use very explosive movements to maximize the slow twitch muscle fibers. Then you look at the physiques of bodybuilders and they are getting different results with slow, heavy reps. Incorporating both slow and explosive movements in the same exercise will give you the best of both worlds and ensure you are getting the most out of your time at the gym.
If you find yourself completing your lifts in under 60 seconds even with a 4-5 second negative downswing (or eccentric) movement, then go heavier to ensure you are pushing yourself and tearing the muscle as much as possible.
Make sure to try this on your next lifting session and report back! I look forward to seeing and hearing about your results.
Stay tuned as I will cover more about muscle hypertrophy and how to maximize your workouts.
Happy lifting, and remember RESULTS NOT EXCUSES.