Is it better to do repetitions at a fast speed or at a slow speed? How does repetition speed influence our workouts?
When it comes to lifting weights, do slow and steady reps win the race or is it fast and explosive reps that take the prize?
Well, like many debates in the fitness industry, the idea of slow versus fast reps has compelling evidence on both sides.
When it comes to slow versus fast reps, we must first understand the importance of rep speed.
In strength training parlance, repetition speed means how fast you lift a weight or resistance. Repetition speed is demonstrated through the eccentric and concentric part of a movement.
The concentric or lifting phase of the movement occurs when you begin an exercise. It is the lifting part of the movement.
When the top of a movement is reached, this is called the isometric phase, there we pause for about a second and then lower the weight to the starting position; this phase of descent represents the eccentric part of the movement.
For example, when doing the bicep curl, the concentric phase occurs when we bring the weight to the shoulders.
After stopping at the top (the isometric phase), we slowly lower the weight to the starting position, which represents the eccentric phase.
Typically, the speed of this “normal” rep takes one to two seconds for the ascent phase, with a pause at the top of a second, followed by a range of one to three seconds to lower the load.
Now, changing this speed, either to a faster rep rate or to a slower rep rate, alters your training goal.
Benefits of training at a low repeat speed
Whether you’re just starting out or have been lifting weights for years, you may be wondering what the best workout is for building muscle fast.
If your goal is hypertrophy or increasing muscle size, then focusing on slow reps to build muscle is a good place to start.
When you do a slow rep workout, your muscles experience a longer time under tension than they would if you were doing normal or fast reps.
Time under tension refers to the amount of time a muscle is under tension. This can lead to a greater increase in muscle size than faster reps that spend less time under tension.
We have analyzed this in more depth: Time under tension.
Performing a slower movement for strength training while using lighter loads is also a safer approach for beginners.
Also, slowing down allows us to focus on technique and make sure we are doing the movement correctly.
Benefits of training at a high repeat speed
If your fitness goals involve strength and power, then you can use a faster rep speed.
According to a study (source), participants who trained for eight weeks with a high intensity, low load program demonstrated increased power.
While faster reps are generally linked to more explosive movements that result in power development, training at this pace can also produce gains in muscle size.
From what we can say that at the level of muscle development, training with high repetition speeds will also favor the process.
What if we combine slow and fast reps?
While both styles of training serve a specific purpose, we shouldn’t make the mistake of making the mistake of incorporating slow and fast reps into your overall training.
According to a 2016 meta-analysis published in the Journal of Sports Medicine, using a fairly wide range of rep durations is ideal if your primary goal is to maximize muscle growth.
The bottom line is this: With both methods you will benefit from strength training with both repetition speeds.