What is the best rep tempo for hypertrophy? (The force-velocity relationship explained)
Your rep tempo (speed) will ALWAYS be determined by how much weight you’re lifting relative to your one-rep max (100% 1RM).
This can be explained by the force-velocity relationship.
In other words, the greater the force required to lift a weight, the slower the velocity (and vice versa).
This is why you rarely see guys in the gym lifting their one-rep max with a fast bar speed (more often than not it’s a slow, grindy rep).
Interestingly, this also applies to sports where throwing objects is involved.
For example, elite shot-putters spend about 50% of their total training time on heavy resistance training, whereas javelin throwers spend only 15-25% of their training lifting weights.
The reason?
The weight of the implements they use is different (7.2 kg vs 0.8 kg).
Essentially, the javelin thrower doesn’t need to be concerned with maximal strength because the weight of the javelin is close to 0.
Whereas the shot-putter needs to increase their rate of force development to throw the shot put faster.
If you think about it this strikes a similar parallel to bodybuilding vs powerlifting.
Bodybuilders aren’t at all concerned with lifting maximum poundage’s.
They typically use a very low percentage of their one-rep max (e.g. 50% 1RM).
This is why speed isn’t a factor in their training but time under tension is.
On the other hand, the main goal of a powerlifter IS to increase their one-rep max.
So they focus on fast reps to increase their rate of force development when lifting heavy.
If you’re trying to build muscle and strength then you’re going to fall somewhere in the middle of this spectrum.
That said, I believe fast reps are superior as they allow you to build explosive strength and they minimise metabolic fatigue.
This way you can do more total volume in your training.
To make my point I’d like to point to this study.
In the study, 59 participants were randomised into 3 groups:
Group 1 used a 2-4 rep tempo, Group 2 used a 10-10 rep tempo, and Group 3 used a 30-30 rep tempo.
All three groups were placed on a 2 days/week training program for 10 weeks in total.
The results showed that all three groups gained similar amounts of muscle.
This demonstrates that a slow lifting tempo does NOT increase muscle growth in any significant way.
Furthermore, industry titans Brad Schoenfeld and James Krieger recently conducted a review and meta-analysis of all the research on rep duration for muscle growth.
Here was the criteria they used for the review:
(1)The studies directly compared different training tempos using both concentric and eccentric repetitions.
(2)The studies had a minimum duration of 6 weeks.
(3) Sets were carried out to volitional muscle failure (i.e. the point where you can’t do any more reps unassisted).
They found that muscle growth is similar when training with repetition duration’s ranging from 0.5 to 8 seconds.
In addition, they concluded that training with very slow rep tempos (>10s per repetition) is inferior for muscle building.
That said, here are my guidelines for finding your ‘optimal’ lifting tempo:
- Control the negative. On the lowering portion of the rep, it’s a good idea to use a slow-moderate tempo to stay ‘tight’ and keep the bar under control.
- Use a slight pause. Doing a 1 or 2 second pause at the bottom of the rep is GREAT for increasing muscle activation and building explosiveness.
- Accelerate as fast as you can. On the ‘positive’ portion of the rep, you want to be as explosive as you can while still retaining good form and bar control. Research has shown that doing this can lead to faster strength gains.
