Slow Reps vs Fast Reps: Which Builds More Muscle?
Rep speed has been a hot topic in the muscle-building industry. Do you want to move the weight slowly and with
control or explode the weight up? Although both styles are useful in strength training, it depends on your goals,
experience and phase you are training in. Slow Reps vs Fast Reps: Which Is Best for Muscle Growth? Let’s get into
the science behind slow reps vs fast reps to determine which method actually triggers more muscle growth!
What Are Slow Reps?
Slow reps consist of lifting the loading and returning it’s starting position at a slower speed, usually between
3 and 6 seconds per rep, a very common tempo repetition is 3-1-3, three seconds up, one second pause, three
seconds down. This way you are making time under tension (TUT) longer and we know TUT is one of the unit of hypertrophy.
Benefits of Slow Reps:
- Increased Time Under Tension: Increased muscle fiber activation and metabolic stress.
- Improved Mind-Muscle Connection: Increases control and engagement of the muscle you’re targeting.
- Less Risk of Injury: Move with control to minimize jerky movements and bad form.
- Perfect for Hypertrophy: Excellent for developing muscle-build phases of training.
What Are Fast Reps?
Fast reps are completed with a faster cadence, sometimes taking 1 to 2 seconds on the way up and down.
It emphasizes explosive power and is often used in athletic training and powerlifting.
Benefits of Fast Reps:
- More Power & Strength: Stimulating fast-twitch fibers, the muscles for explosive power.
- More Volume, Less Time: High rep counts in less time.
- Faster Athletes: Used in the NFL combine and by professional athletes everywhere, speed and agility increase when using the Power Chute.
- Increases Nervous System Efficiency: Trains your CNS to handle heavier loads.
Slow Reps vs Fast Reps When it comes to Muscle Growth
The secret to hypertrophy is progressive overload and training volume. Both slow and fast reps have
muscle-building potential, but their mechanics are not the same:
- Repetition Speed Muscle Fiber Target Ideal For Muscle Growth Potential
- Slow Reps Type I (slow-twitch) Hypertrophy, Endurance High (because of TUT)
- Fast Reps Type II (fast twitch) Strength, power, performance Moderate to high
Hang reps (slower) are usually more suitable for muscle isolation and fatigue-based growth. They focus on
eccentric (negatives) control, since that creates more muscle damage (temporarily), one of the major drivers of hypertrophy.
Fast reps, by contrast, are best for neuromuscular efficiency and help you lift heavier loads. Although they might not
optimise TUT, they do recruit high threshold motor units which contribute towards muscle growth differently.
Scientific Evidence
Both slow and fast reps stimulate hypertrophy when performed with equivalent overall volume, according to a
study published in the Journal of Strength and Conditioning Research. But slow reps do frequently result in more
muscle soreness and metabolic stress — two of the hallmarks of muscle growth.
Another study suggests that quicker lifting speeds elicit more strength and power. So if you’re looking to lift heavy
or move explosively, quicker reps could be more effective.
Best Approach: Combine Both
Rather than picking one type, it’s probably ideal to work in both kinds of slow and fast reps in your exercise program.
Here’s how:
- Hypertrophy Focus (Bodybuilding): Slow, controlled reps, moderate weight, higher reps (8–12).
- Strength Focus (Powerlifting): Use fast, explosive repetitions, lift as heavy as you can and keep the reps low (3–6).
- Athletic Training: Focus mainly on your speed work and add a little bit of slow tempo accessory lifts for balance and stability.
Final Thoughts
So, what puts more muscle on your bones — slow reps or explosively fast reps? The correct response is
that it depends (on how you use them). Slow rep style works the tension and control aspect of muscle, fast reps
build strength and explosive power. For building the muscle, you should strive for a well-rounded regimen that
incorporates a range of tempos specific to what you’re trying to achieve.
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