Slow Reps vs Fast Reps: What Pace Should You Choose?

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: What Pace Should You Choose?
Photo by Luke Witter / Unsplash
5 min. read 10/5/2023, 7:53 PM

When it comes to strength training to reach a certain fitness goal, you'll do anything to ensure your routine is as effective as possible. From choosing the best exercises to choosing the right exercise tempo - these things are important!

How fast or slow you complete your reps can make a difference in your routine, especially if you're trying to get the best results possible in a certain amount of time. So, what exercise tempo should you be following? Fast or slow reps? It all depends on what goals you have. To help you decide, we'll explore the fundamentals of fast and slow reps, the nuances of eccentric, concentric, and isometric contractions, and the respective benefits of each method.

Understanding Eccentric, Concentric, and Isometric Contractions

Before delving into fast and slow reps, let's learn about the three primary types of muscle contractions:

  1. Concentric Contraction: This is the phase of a muscle contraction where the muscle shortens while generating force. For example, during a bicep curl, the concentric phase occurs when you lift the weight toward your shoulder.
  2. Eccentric Contraction: Eccentric contractions happen when a muscle lengthens while producing force. Using the same bicep curl example, the eccentric phase takes place as you lower the weight back down slowly and with control.
  3. Isometric Contraction: Isometric contractions occur when a muscle generates force without changing its length. In a plank exercise, your core muscles are engaged in an isometric contraction as you hold your body in a stable, static position.

The Benefits of Fast Reps

Knowing the benefits of slow vs. fast reps will help you decide what approach is right for you. That said, fast repetitions offer the following benefits...

  1. Power development: Fast reps are ideal for enhancing explosive power and speed. Athletes in sports like sprinting, basketball, and weightlifting benefit from this type of training to improve their performance.
  2. Muscle activation: Fast reps recruit a high number of muscle fibers due to the rapid contraction and relaxation of muscles. This leads to increased muscle activation and the development of fast-twitch muscle fibers, which contribute to explosive strength.
  3. Time efficiency: Fast reps require less time to complete a set compared to slow reps. This makes them suitable for individuals with busy schedules who still want an effective workout.
  4. Cardiovascular benefits: Fast reps can elevate your heart rate significantly, providing cardiovascular benefits akin to high-intensity interval training (HIIT).

How fast should you go?

Your tempo is important, so with fast reps, you should be aiming for one to two seconds per rep. It also depends on the exercise. For example, if you're doing jumping jacks during HIIT you might be able to go through more than one rep per second compared to doing walking lunges.

Just because you're going fast doesn't mean you should rush through your reps and compromise your form. Rushing through the movement can reduce the effectiveness which means not building as much power and strength! So, always make sure your form is correct, don't just rush through the reps.

The Benefits of Slow Reps

Slow repetitions, where each phase of the repetition is controlled and deliberate, offer a different set of benefits:

  1. Muscle hypertrophy: Slow reps provide extended time under tension for the muscles, a crucial factor for muscle hypertrophy (growth). This approach targets the slow-twitch muscle fibers and promotes muscle size and definition.
  2. Improved technique: The slower pace of these reps encourages proper form and technique, reducing the risk of injury and ensuring that muscles are the primary focus during the exercise.
  3. Mind-muscle connection: Performing slow reps allows individuals to establish a strong mind-muscle connection. This heightened awareness of muscle engagement can enhance overall performance and muscle targeting.
  4. Reduced momentum: Slow reps minimize the use of momentum, ensuring that the resistance is primarily handled by the targeted muscles, rather than external forces.

How slow should you go?

The key is to keep your tempo slow enough to have your muscles under tension a little bit longer than usual during the eccentric phase (lowering movement), and then pick it up for the concentric phase. You don't have to take 30 seconds lowering into your deadlift, we're talking about a tempo of 2-5 seconds for the eccentric movement. You want to ensure you're focusing on controlling the movement and feeling your muscles engaging, not just relying on momentum.

Choosing the right approach

The choice between fast and slow reps hinges on your specific fitness goals, experience level, and preferences. Follow these guidelines to help you decide which approach is right for you:

  1. Muscle building: If your primary aim is muscle hypertrophy, slow reps are generally more effective due to prolonged time under tension.
  2. Strength and power: For those looking to improve explosive strength and power, fast reps or a combination of fast and slow reps (periodization) may be more appropriate.
  3. Balanced approach: A well-rounded workout routine may benefit from incorporating both fast and slow reps. Utilize fast reps sparingly for power development and slow reps for muscle growth and control.
  4. Safety first: Regardless of your chosen rep speed, prioritize proper form and technique to reduce the risk of injury.
  5. Individualization: Tailor your approach to your unique needs and body type. Experiment with different rep speeds and monitor your progress to determine what works best for you.

The fast reps vs. slow reps debate is not about one being definitively better than the other. Instead, it's about understanding their distinct benefits and how they align with your fitness objectives. Both methods have their place in a well-structured training regimen. By comprehending the science behind eccentric, concentric, and isometric contractions, as well as the advantages of fast and slow reps, you can craft a workout routine that maximizes your potential and helps you achieve your fitness goals effectively and safely.