When it comes to lifting weights, do slow and steady reps win the race or do fast and explosive reps for power take the prize? Well, like many debates in the fitness industry, the idea of slow vs. fast reps has compelling evidence on both sides.
Slow vs. Fast Reps
When it comes to slow vs. fast reps, you first need to understand the significance of repetition speed. In strength training language, repetition speed means tempo, or how fast you lift a weight or resistance. Tempo is demonstrated through both the eccentric and concentric part of a movement.
The concentric or lifting phase of a movement happens when you begin an exercise. It is the lifting part of the move. When you reach the top of a movement, which is called the isometric phase, you pause for about one second and then lower the weight to the starting position. This lowering phase represents the eccentric part of the movement.
For example, when doing a biceps curl, the concentric phase happens when you curl the dumbbell up towards your shoulders. After pausing at the top (isometric phase), you lower the weight slowly to the starting position, which represents the eccentric phase. Typically, the speed of this rep follows a one to two seconds up (pause at the top for one second), followed by a one to a three-second range when lowering the weight. Changing this tempo, to either a faster rep pace or slower rep pace, alters the goal of your workout.
Benefits of Lifting Weights Slowly
When you do a slow rep workout, your muscles experience a greater time under tension than they would if you were doing fast reps. Time under tension refers to the amount of time a muscle is under strain. This can lead to a greater increase in muscle size than faster reps which spend less time under tension.
Taking a slower approach to strength training while using lighter weights is also a safer approach for beginners. Slowing the tempo down allows you to focus on form and make sure you're doing the move correctly.
Why You Should Consider Fast Reps
If your fitness goals involve strength and power, then using a faster tempo may be more beneficial. According to a 2015 study published in Physiological Reports, participants that trained for eight weeks at a high intensity, low volume resistance program demonstrated increased bench press and lean body arm mass with fast rep resistance exercise training. While faster reps are generally linked to more explosive movements that result in power, training with this tempo can also produce gains in muscle size.
Combining Slow and Fast Reps
While both training styles serve a specific purpose, you can't go wrong incorporating slow and fast reps into your overall workout. According to a 2016 meta-analysis published in the Journal of Sports Medicine, using a fairly wide range of repetition durations is ideal if the primary goal is to maximize muscle growth. The bottom line is this: You will benefit from strength training with both tempos.
- Journal of Physiological Reports: The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men
- Journal of Human Kinetics: Does Tempo of Resistance Exercise Impact Training Volume?
- American Council on Exercise: How Many Reps Should You Be Doing?
- American Council on Exercise: Weight Lifting Tempo & Sets
- Journal of Sports Medicine: Effect of repetition duration during resistance training on muscle hypertrophy