When you train with weights, there are many variables you can adjust to change the stimulus you place on the muscles you’re working. Most people focus on the weight or resistance and the number of reps and sets rather than the tempo. However, the tempo you use when you lift can affect your training and the results you get too.
Some experts recommend lifting with a slow tempo to increase the time the muscle is under tension and maintain better control over the weight. But there are pros and cons to using a slow tempo, just as there are advantages and disadvantages of using a fast tempo. Let’s look at the pros and cons of slowing down the tempo of your reps.
The Pros of Lifting with a Slow Tempo
The biggest benefit of training with a slow tempo is it allows you to focus more on form. The slower the tempo, the more you can concentrate on the muscles you’re working. Mental focus counts for hypertrophy gains! Studies show that people build more muscle when they concentrate with laser-like precision on the muscles they’re working rather than letting their minds wander during a training session. When you focus on a muscle while lifting, it increases the activation of that muscle and that can lead to greater hypertrophy gains. It’s also safer to lift a heavy weight with a slow tempo since you’re eliminating momentum and reducing your risk of injury.
Lifting with a slower tempo also increases the time a muscle is under tension. Some research reveals that greater time under tension boosts hypertrophy gains. For example, a small study of eight men showed that slowing down the tempo and increasing the time under tension boosted muscle protein synthesis more.
Why might this happen? One theory is that a slow tempo creates more metabolic stress and muscle cell swelling that can trigger hypertrophy gains. However, not all studies show that time under tension is important for muscle growth, especially when you take total training volume into account.
The Cons of Lifting with a Slow Tempo
The time it takes to do a repetition at an average tempo is 3 to 4 seconds. Increasing the tempo to 1 or 2 seconds has advantages too, especially if your goal is to build power. When you boost the tempo of a lift and make it more explosive, you move the weight through space faster and that boosts power. Lifting with a quicker tempo also taps into those fast-twitch muscle fibers sooner, the ones optimized for strength and power. Also, you won’t make significant power gains if you stick to a slow lifting tempo all the time.
Even though the time a muscle is under tension increases when you slow the tempo, there are also advantages to speeding up. In fact, using a fast tempo may give you a slight hypertrophy edge. A meta-analysis by Dr. Brad Schoenfeld found that subjects who used a faster tempo gained a little more muscle mass relative to those who lifted at a slower tempo. However, the difference wasn’t significant.
Another consideration is how much time you train. If you have limited time to work out, using a slow tempo on every set will eat up more of your training time. Therefore, you’ll do fewer sets or exercises than if you picked up the tempo. Lifting with a faster tempo and completing more total volume may ultimately help you gain more muscle. There’s also the fatigue factor. When you use a slow tempo, it fatigues your muscles quicker and you may have to cut your training volume because of muscle fatigue.
Finally, using a slow tempo leads to more muscle damage, especially if you reduce the tempo during the eccentric phase. This may also lead to more muscle soreness. You might equate muscle soreness with greater muscle growth, but not all studies support this link. There’s little evidence that muscle soreness is a marker for greater muscle protein synthesis or muscle hypertrophy.
Fatiguing Your Muscles is Key
Ultimately, for hypertrophy gains, fatiguing your muscles matters most for growth. You can fatigue your muscles and make them grow using a slow tempo or a fast one. The key is to exhaust your muscles by the last rep and do enough volume. However, using a faster, almost explosive tempo is superior for making power gains. Even if you lift the weight explosively, keep the lowering phase slow and controlled. For example, you might lift the weight in a second but take 2 to 4 seconds to lower it.
The Bottom Line
Tempo is one of several factors you can tweak to change the stimulus you place on your muscles. Using a slow tempo increases the time the muscle spends under tension and allows you to focus on form. When you’re first starting out, use a slow tempo, so you’ll learn to do the exercise quickly, and not adopt bad habits.
Once you’ve been training for a while, increasing the tempo, and even doing explosive training will place a different stimulus on your muscles. It can be helpful for breaking out of a plateau or avoiding one to begin with. Plus, boosting the tempo of your reps will help you build explosive strength and power.
Whether you use a slow or fast tempo more often should depend on your goals. If you’re trying to build more muscle power, focus some time on explosive lifting. But if you’re trying to maximize hypertrophy gains, use both tempos—fast and slow to vary the stimulus on the muscle. Just make sure you’re comfortable with an exercise and can do it with good form before doing that exercise explosively since the risk of injury is higher.
- Fitness Science. “Fast or Slow Reps, What is Most Effective?”
- J Physiol. 2012 Jan 15;590(2):351-62. doi: 10.1113/jphysiol.2011.221200. Epub 2011 Nov 21.
- com. “Try Different Rep Speeds to Build Strength and Size”
- J Physiol. 2012 Jan 15; 590(Pt 2): 351–362. Published online 2011 Nov 21. doi: 10.1113/jphysiol.2011.221200.
Related Articles By Cathe: