Should You Lower Weights Slowly for More Muscle Growth? New Research Challenges the Norm

Key Takeaways of Eccentric Workouts for Muscle Growth

• Fast eccentric workout movements (i.e., fast eccentric contractions) may be better for explosive power: Lowering weights quickly improves jump performance, making it great for athletes training for speed and explosiveness.
• Slow eccentric lifting could help trained lifters get stronger: If you’ve been lifting for a while, taking your time on the way down might give you a slight strength boost.
• Muscle growth? The jury’s still out: There’s no clear advantage to lowering weights fast or slow when it comes to building size. What matters more is total volume and intensity.

Does Slowing Down Really Help in an Eccentric Workout?

If you’ve been in the gym for a while, you’ve probably heard this advice: Lower the weight slowly for maximum muscle growth. This belief traces back to early bodybuilding methodologies from the 1970s-90s, where trainers emphasized “time under tension” (TUT) as a key driver of hypertrophy. Figures like Arthur Jones and the creators of Nautilus training machines popularized slow negatives, believing they led to greater muscle fiber breakdown and, ultimately, more growth.

That lowering phase—the part where you control the weight back down—is what we call an eccentric contraction exercise. It’s been widely promoted in strength training circles as a fundamental technique for hypertrophy. However, modern research suggests that while eccentric training is essential, the exact tempo may not be as crucial as once believed.

A 2023 study backs this up, showing that resistance training, in general, leads to muscle hypertrophy. Still, the extent of growth depends on training intensity, volume, and the type of exercises performed. This ties in with the long-standing idea that slowing down the eccentric workout phase can help recruit more muscle fibers, which in turn could maximize muscle growth.^1,2 The idea is that more time under tension (i.e., lowering the weight slowly results in more tension placed on muscle) equals more muscle, and to get that, you should take your time on the eccentric contraction exercise phase of each rep.

But what if that’s not entirely true?

A new systematic review and meta-analysis by Christian Houmann Amdi and Andrew King put this long-held belief under the microscope. The study, published in SportRxiv, analyzed multiple studies comparing fast (≤2 seconds) and slow (>2 seconds) eccentric workout tempos to see which approach actually delivers better strength, hypertrophy, and power gains.³ The results were not what many bodybuilders have believed to be true and slow eccentric contractions and muscle growth.

The Old vs. The New: What Science Says About Eccentric Contraction Exercises

For years, research has pointed both ways.

• A 2017 study reviewed 15 studies comparing eccentric and concentric training and found that eccentric contractions led to an average hypertrophy gain of 10.0%, compared to 6.8% for concentric contractions.⁴
• However, another study found that super slow reps (10+ seconds) actually produced worse muscle growth than more moderate tempos (0.5–8 seconds).⁵ So, while a little control is good, dragging things out too much might not be.

On the flip side, when people lift explosively, they tend to gain more strength. A 2023 meta-analysis found that fast concentric movements (the lifting phase) led to better strength gains than slow ones.⁶ The reasoning? Slowing down the rep might reduce neuromuscular performance and motor unit recruitment, limiting your potential for strength gains.

To make things more confusing, a 2017 study noted that eccentric overload training did not provide additional hypertrophy benefits compared to traditional resistance training.⁴

Clearly, there’s a lot of conflicting information. That’s where this new study comes in.

What the Research Found: Faster vs. Slower Eccentric Lifting

The new 2025 study analyzed eight different studies with 148 participants (about half of them were experienced lifters) and looked at three major factors:

1. If You Want to Jump Higher, Lower the Weight Faster in Your Eccentric Workout

One of the biggest takeaways? Fast eccentrics significantly improved countermovement jump height. Athletes who lowered weights quickly saw better gains in explosive power than those who took their time.

Why does that happen? It comes down to something called the stretch-shortening cycle —the natural ability of muscles to store and release energy quickly. If you slow things down too much, you lose that stored energy, making movements like jumps and sprints less effective.

• Who should care? If you’re a sprinter, weightlifter or play sports requiring quick bursts of power, stop wasting time lowering the bar too slowly.

2. Slower Eccentric Lifting Might Be Better for Strength (But Only for Experienced Lifters)

When it comes to getting stronger, the results weren’t as clear-cut. Overall, there was no major difference between slow and fast eccentric contraction exercises.

But—there’s a twist.

Trained individuals saw slightly better strength gains with slower eccentric lifting.

When volume-load was matched (meaning both groups lifted the same total weight over time), slow eccentrics showed a small advantage.

• What does this mean? If you’re a beginner, tempo doesn’t seem to matter much—just focus on getting stronger and lifting with good form. But if you’ve been training for years, slowing down might help you squeeze out a little extra strength.

3. Muscle Growth: No Clear Winner in Eccentric Lifting

Now, the big question—which tempo builds more muscle? Well, it turns out… neither.

The analysis found no major difference in hypertrophy between slow and fast eccentric contraction exercises.

Some data hinted that slow eccentric lifting might slightly improve hypertrophy in trained individuals, but the evidence wasn’t strong enough to say for sure.

• Bottom line? If your goal is muscle growth, don’t stress about tempo. Focus on volume, intensity, and progressive overload instead.

How Should You Train?

So, what should you do with this information? Here’s a practical breakdown based on your training goals:

Training for Power? Go Fast in Your Eccentric Workout.

If you’re an athlete, sprinter, or Olympic lifter, focus on faster eccentric contraction exercises.

• Lower the weight under control, but don’t drag it out.
• Prioritize explosive exercises like squats, deadlifts, and plyometrics.

Training for Strength? Try Slowing Down (If You’re Experienced).

If you’re a beginner, tempo doesn’t really matter—just train hard and consistently.

• If you’re experienced, experiment with slower eccentric lifting and see if it helps.
• Stick to heavy, low-rep sets (3-6 reps) with controlled eccentrics.

Training for Muscle Growth? Focus on Volume, Not Just Eccentric Lifting.

Whether you lower the weight fast or slow won’t make a huge difference.

• Total volume (sets × reps × weight) is what matters most.
• Aim for moderate reps (6-12) and progressively overload your training.

Final Thoughts: Should You Slow Down Your Eccentric Lifting?

So, what’s the verdict? Should you slow things down or speed them up?

It depends.

• If you’re training for power—fast eccentric contraction exercises are the way to go.
• If you’re focused on strength—slow eccentric lifting might offer a small advantage (but mostly for advanced lifters).
• If you just want to get bigger—tempo doesn’t really matter. Focus on training hard, eating enough, and recovering well.

There’s no one-size-fits-all answer. The best training strategy is the one that aligns with your goals. So instead of obsessing over tempo, use a mix of both fast and slow eccentrics in your workouts and find what works best for you.

References

1               Ihsan, F., Nasrulloh, A., Nugroho, S. & Yuniana, R. Effect Weight Training on Muscular Hypertrophy: A Systematic Review. Pedagogy of Physical Culture and Sports 27, 439-447 (2023). https://doi.org/10.15561/26649837.2023.0601

2               Azevedo, P., Oliveira, M. & Schoenfeld, B. Effect of different eccentric tempos on hypertrophy and strength of the lower limbs. Biology of Sport 39, 443-449 (2021). https://doi.org/10.5114/biolsport.2022.105335

3               Amdi, C. & King, A. The effect eccentric phase duration on maximal strength, muscular hypertrophy, and countermovement jump: A systematic review and meta-analysis. (2024).

4               Schoenfeld, B. & Grgic, J. Eccentric Overload Training: A Viable Strategy to Enhance Muscle Hypertrophy? Strength and Conditioning Journal, 1 (2017). https://doi.org/10.1519/SSC.0000000000000351

5               Schoenfeld, B. J., Ogborn, D. I. & Krieger, J. W. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Med 45, 577-585 (2015). https://doi.org/10.1007/s40279-015-0304-0

6               Hermes, M. J. & Fry, A. C. Intentionally Slow Concentric Velocity Resistance Exercise and Strength Adaptations: A Meta-Analysis. J Strength Cond Res 37, e470-e484 (2023). https://doi.org/10.1519/jsc.0000000000004490