How Slow Should You Go? New Research on Tempo Training and Rep Speed ( – SET FOR SET

Quick reps vs. sluggish reps: That are higher for muscle hypertrophy?

Time-under-tension and tempo coaching. Two strategies of bodybuilding that manipulate the pace of a repetition in an try to extend muscle progress. Identical to adjusting the load of a carry or rising coaching frequency, this coaching strategy treats the pace of a repetition as a variable that may be altered to attain completely different outcomes.

However does it work? Does merely performing a sluggish rep lead to nice features, or is it higher should you go sooner? A big meta was simply launched that has a solution to: how briskly ought to a rep be?

The Examine:  How sluggish must you go? A scientific overview with meta-analysis of the impact of resistance coaching repetition tempo on muscle hypertrophy.

Resistance coaching tempo, or the pace at which you carry and decrease the burden, has lengthy been a subject of debate on the earth of bodybuilding and power coaching. The dialog goes additional than merely suggesting to carry out a rep, “sluggish and managed”.

Somewhat, proponents counsel that purposefully performing a rep slower or sooner can elicit completely different outcomes. Normal ideas included;

• Slower reps improve “time beneath pressure” and mechanical stress, leading to better muscle progress.
• Sooner reps trigger better muscle activation and better drive output, leading to better power features.

Up to now, older critiques tended to lump whole rep length collectively quite than isolate the phases. Nonetheless, a brand new systematic overview and Bayesian meta-analysis (2025) simply revealed is the primary to separate eccentric (decreasing) and concentric (lifting) tempos to see if manipulating tempo actually impacts hypertrophy.

As an alternative of simply “sluggish vs. quick reps”, they checked out eccentric vs. concentric tempo results on muscle progress.

Outcomes & Key Findings

The researchers carried out a big meta-meta, pooling from a massive provide of research. A couple of key factors concerning the research choice embrace

• Examine pool: 14 randomized trials, 278 individuals (principally younger adults, solely 73 ladies, and some educated lifters)
• Examine length: Most research lasted 6–12 weeks, with individuals coaching 2–4 occasions per week.
• Muscle tissues studied: Primarily quadriceps and biceps; mixture of single-joint and multi-joint workout routines.
• Measurement instruments: Ultrasound, MRI, DXA, biopsies, or limb circumference.
• Evaluation technique: Bayesian hierarchical meta-analysis, which estimates the chance of 1 tempo being superior quite than counting on easy “significance.”

Researchers ran the numbers and got here up with 5 essential findings.

1. Quick vs. sluggish, each elevated muscle progress. When analyzing muscle progress inside every group, each quick and sluggish tempos yielded stable features.

This signifies that researchers examined whether or not quick repetitions and sluggish repetitions can construct muscle independently.

When evaluating the impact measurement (i.e., the magnitude of the advance), sooner tempos confirmed a medium impact measurement of 0.43, whereas slower tempos had an impact measurement of 0.34.

This means each teams constructed noticeable muscle with neither displaying a big benefit.

2. Direct comparability: no clear winner. When researchers immediately in contrast sooner reps and slower reps, sooner reps had a slight statistical edge (imply distinction of 0.09). Nonetheless, the chance that this edge held any significance in the actual world was solely 45%.

This means the likelihood of it having an precise impact is low.

3. Optimum speeds for concentric and eccentric phases. When damaged down by section, the concentric section trended barely in favor of sooner tempos. The eccentric (decreasing) portion confirmed nearly no distinction. Nonetheless, any variations had been primarily negligible.

This means they made little to no distinction.

4. Higher vs. decrease physique. This was an fascinating part because the researchers examined whether or not completely different physique components could be affected by rep pace. Nonetheless, tempo did not matter for the physique area.

This implys that slowing down squats will not improve the mass of your legs, whereas dashing up curls does not lead to greater biceps. Each higher and decrease our bodies responded the similar approach regardless of tempo.

5. Coaching to failure. This was one other fascinating part of the research, because it checked out whether or not these speeds make a distinction in relation to training to failure. Perhaps it has a bigger impact when you do not prepare near failure? Nicely, they did discover some fascinating outcomes.

• When individuals educated wanting failure, sooner eccentrics appeared barely higher.
• When individuals educated to failure, slower eccentrics had a modest edge.

Nonetheless, each results had been small and inconsistent.

This means the variations weren’t robust sufficient to justify altering how most individuals ought to prepare.

How It Suits with Earlier Analysis

The findings above primarily constructed upon data from previous analysis with no main contradictions, however there had been some.

1. Schoenfeld et al. (2015) reported similar hypertrophy across tempos starting from 0.5 to eight seconds. This new meta-analysis confirms the discovering however builds upon it by guaranteeing that is true for eccentric versus concentric actions independently.

2. Hackett et al. (2018) advised slower tempos may assist quads, whereas sooner tempos benefited biceps. The brand new evaluation finds no constant regional benefit as soon as variables are managed.

3. Wilk et al. (2021 narrative overview) hypothesized that slower eccentric contractions and sooner concentric contractions could also be optimum and are probably preferrred for power and mass growth. This is considerably contradictory to the brand new 2025 meta, which reveals no clear hypertrophy profit for both section.

Sensible Takeaways

The clearest message from this paper is that tempo does not considerably have an effect on hypertrophy, so long as you are coaching arduous and with ample quantity. Each quick and sluggish reps construct muscle successfully.

After we mix this data with the info we mentioned above regarding power, listed below are 3 pointers on rep pace for power and hypertrophy.

1. Concentric Contraction: Carry out rapidly and beneath management
2. Eccentric Contraction: Sluggish and managed eccentrics 
3. All the time Management The Load: We’ll say it once more, at all times management the load

We examined this matter in its entirety earlier than this research was launched and got here to the same conclusion – you can review it here.

That mentioned, tempo can nonetheless be a great tool relying in your scenario:

• Rehab or joint ache: Slower tempos scale back joint stress and assist preserve management.
• Energy and explosiveness: Sooner tempos are extra sport-specific and construct price of drive.
• Selection and fatigue administration: Altering tempo can present novelty and assist handle coaching stress with out affecting progress.

With all that mentioned, the large levers for hypertrophy nonetheless stay: coaching quantity, progressive overload, and proximity to failure. Tempo can simply be a enjoyable little variable to play with should you’re .

References

1. ENES, A., PIÑERO, A., HERMANN, T., ZAMANZADEH, A., HENNESSY, T., MONTENEGRO, D., PARNELL, C., JIA, A., WEITZMAN, T., WOLF, M., KORAKAKIS, P.A., SWINTON, P.A. and SCHOENFELD, B.J. [2025]. How sluggish must you go? A scientific overview with meta-analysis of the impact of resistance coaching repetition tempo on muscle hypertrophy. Journal of power and conditioning analysis (pre-print)
2. Hackett, D. A., Davies, T. B., Orr, R., Kuang, Okay., & Halaki, M. (2018). Impact of motion velocity throughout resistance coaching on muscle-specific hypertrophy: A scientific overview. European Journal of Sport Science, 18(4), 473–482. https://doi.org/10.1080/17461391.2018.1434563
3. Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2015). Impact of repetition length throughout resistance coaching on muscle hypertrophy: A scientific overview and meta-analysis. Sports activities Medication, 45(4), 577–585. https://doi.org/10.1007/s40279-015-0304-0 
4. Wilk, M., Zajac, A., & Tufano, J. J. (2021). The affect of motion tempo throughout resistance coaching on muscular power and hypertrophy responses: A overview. Sports activities Medication, 51, 1629-1650. https://doi.org/10.1007/s40279-021-01465-2