Slow Reps vs Fast Reps: Which is More Effective?

Not sure if you should use fast or slow reps for muscle growth and other fitness goals? We’re here to help you figure it out!

Slow Reps vs Fast Reps: Which is More Effective?
María Rubio María Rubio
4 min read

When it comes to working out, there are many approaches that you can take depending on what you want to achieve. You can try fast and intense workouts, low-impact exercises, or maybe somewhere in between, and a good way to play with that intensity is by either slowing down or speeding up your reps!

In the fitness world, this is known as your tempo, and as an active person you’re probably familiar with both slow and fast tempos and might even have a preferred one. However, both tempos have their benefits, and the one you try will depend on your fitness level, goals, and overall training preference.

To help you find the ideal tempo for your workout routine, or learn the perfect balance between both, we’ve put together all the info you need about slow reps vs. fast reps, their benefits, and the best time to practice each. So keep reading!

What exactly is exercise tempo?

When we talk about tempo in the fitness world, we’re talking about the total time in which you go through the three parts of an exercise – the concentric phase, the isometric phase, and the eccentric phase. To better understand slow vs. fast reps, let’s talk about these phases first…

During the concentric phase, your muscles shorten or contract as you exert maximal force against a load. The eccentric phase, on the other hand, is when your muscles lengthen, less force is used, and the resistance of the load is greater. And finally, the isometric phase is simply the part in between both, when there is no motion occurring.

Let’s take bench presses as an example. When you’re pushing the weight away from your body, you’re performing a concentric movement as the force you exert is greater than the resistance of the load. The pause at the top is the isometric phase, and the eccentric phase happens when you bring the weight back down.

Tempo is generally expressed by assigning a number of seconds to each phase. For example, a tempo of 2-1-3 means that you’ll spend 2 seconds in the concentric phase (exerting maximal force), 1 second in the isometric phase (holding), and 3 seconds in the eccentric phase (reversing the movement).

Slow reps vs. fast reps

Now that you’re familiar with tempo and the three phases of exercise, we can talk about rep speed. When it comes to choosing how slow or how fast your repetitions will go, you essentially need to pick the duration of each phase. However, it all depends on what you want to achieve, so let’s get into it…

Who should perform slow reps?

Slowing down your reps means that your muscles will spend more time under tension, as the movement will take longer to complete from start to finish. More time under tension means more damage to your muscle fibers, which is the basis for muscle hypertrophy, also known as muscle growth!

So, if you’re someone who’s looking to improve your muscle size, slower reps are the ones for you. This is also a great starting point for beginners and those recovering from injuries as slower movements are easier to control, so you’ll be able to handle the weight carefully as you master proper exercise form.

How slow should you go?

You might be relieved to find out that you don’t have to spend 15 seconds in a repetition for it to count as slow. In fact, a study suggests that a rep range of 10 or more seconds might even be counterproductive, with the best hypertrophy results actually showing in rep ranges of 5-8 seconds.

Let’s take a tempo of 8 total seconds and break it down by phase. The most common way to approach slow and controlled reps is by slowing down the eccentric phase, so you could try a tempo of 2-1-5, taking 5 whole seconds to bring the weight back down. Or, you could add a longer isometric hold by using a tempo of 2-4-2 – your choice!

Who should perform fast reps?

When performing faster reps, you’re teaching your muscles to move and exert force more swiftly and efficiently, whether you’re using an external load or not. Force plus speed equals power, meaning that the faster you go while performing your reps, the more muscular power you’ll develop over time!

Not only that, but performing faster reps also helps develop muscular strength, so if you’re looking to get stronger and improve your muscular power, you’ll want to prioritize fast reps. This is the go-to for those who practice high-intensity workouts such as HIIT and CrossFit, as well as powerlifting, all of which require speed, power, and precision.

How fast should you go?

A speed as fast as 1-2 seconds is usually regarded as a good tempo for fast reps, but that changes depending on the exercise. For example, 2 total seconds is a good tempo for exercises such as burpees which have multiple steps, but a movement as simple as mountain climbers will take less than a second for one rep to be completed.

Fast-paced repetitions also tend to completely skip the isometric phase, meaning that a fast rep tempo could look something like 1-0-1, with 1 second dedicated to the concentric and the eccentric phase each without any pause in between. The fastest you can finish one rep, the better for strength and power-specific goals!

Which one is better?

Well, the truth is that one isn’t better than the other, it just depends on what your goals are. There’s the idea that you need to pick one tempo and stick with it to achieve your specific goals, but that’s not really the case. In fact, a combination of both is the best way to achieve your fitness goals – whatever they are!

Performing fast reps when you’re trying to build muscle or slow reps when your goal is muscle strength won’t hinder your progress, but prioritizing the right tempo for the right goals will definitely maximize your gains. Finding the perfect balance between both will help you develop better fitness, allowing you to improve your performance all across the board.

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