Author: Warrior Weights

Lifting speed is described with several overlapping terms, and the research on it measures different outcomes in different groups. This guide reads four PubMed abstracts on 3 November 2026: a 2015 meta-analysis of repetition duration and muscle growth, a 2017 meta-analysis of movement velocity and strength, a 2019 randomised trial of repetition duration, and a 2022 randomised trial of fast and slow tempos. Only the abstracts were used, so details beyond them are not covered. None of the abstracts mentions dumbbells or kettlebells, and this guide makes no claim about them. General information, not training advice.

Four terms, as the abstracts use them

• Repetition duration: the 2015 meta-analysis defines it as the sum total of the concentric, eccentric and isometric components of a repetition, predicated on the tempo at which the repetition is performed. The 2019 trial describes it as the time taken to perform the concentric and eccentric muscle actions.
• Tempo: the 2022 trial compared FAST and SLOW eccentric repetition tempos, written 1-0-1 and 1-0-3 in the abstract.
• Movement velocity: the 2017 meta-analysis treats it as a training variable that can be manipulated and compares fast or explosive training with slower training.
• Time under load (TUL): the 2019 trial matched its groups for load and for time under load.

The 2015 review: hypertrophy and repetition duration

Schoenfeld and colleagues in Sports Medicine included eight studies. Eligible studies were experimental trials that directly compared training tempos, lasted at least 6 weeks, trained to muscle failure, measured muscle changes by biopsy, imaging or densitometry, and used people without a chronic disease or injury. The abstract reports that hypertrophic outcomes are similar when training with repetition durations from 0.5 to 8 seconds. It adds that findings suggest very slow repetitions, over 10 seconds each, are inferior for hypertrophy, but that a lack of controlled studies makes definitive conclusions difficult.

The 2017 review: velocity and strength

Davies and colleagues, also in Sports Medicine, identified 15 studies of healthy adults that compared fast or explosive training with slower training, matched prescribed intensity and volume, and lasted at least 4 weeks. Fast and moderate-slow training produced similar increases in dynamic muscular strength when all studies were included. When intensity was accounted for, the abstract reports a trend for a small effect favouring fast training at moderate intensities, defined as 60 to 79% of one repetition maximum (effect size 0.31, p = 0.06). The abstract calls this a trend. It also reports that strength gains were not influenced by training status and age.

The 2019 trial: three very different speeds

Carlson and colleagues randomised 59 participants to three groups: a 2s:4s repetition (18 people), a 10s:10s repetition (20 people), or a group that performed 30 seconds of eccentric, 30 of concentric and 30 of eccentric action (about 1.5 repetitions, 21 people). Sessions were supervised one-to-one, twice a week for 10 weeks, and the abstract describes the protocol as low-volume, single-set and machine-based, with chest press, leg press and pulldown outcomes. Strength rose significantly for all exercises with no differences between groups, and no statistically significant changes were found in body composition, upper arm and thigh muscle mass or fasted blood glucose. The authors conclude that repetition duration does not affect strength increases in trained participants when exercise is performed to momentary failure.

The 2022 trial: one leg fast, one leg slow

Pearson and colleagues had 13 resistance-trained men train each leg with a different tempo, chosen at random, for 8 weeks, twice weekly, using a single-joint leg extension. Strength (one repetition maximum) rose in both legs: by 17.0% on the FAST leg and 22.1% on the SLOW leg. Muscle thickness at the proximal thigh rose similarly. At the distal thigh the increase was greater on the FAST leg, 5.5% against 2.2%. The SLOW leg had a higher rating of perceived exertion (8.59 against 7.98). The authors conclude that both tempos produced similar muscular adaptations but suggest FAST may give a small hypertrophic advantage at the distal quadriceps.

Why the four results are kept apart

• Different outcomes: the 2015 review measured muscle growth, the 2017 review measured strength, and the two trials measured both.
• Different speeds: the reviews compared repetition durations or velocities pooled from many studies, the 2019 trial compared three very different repetition durations, and the 2022 trial compared two eccentric tempos.
• Different people and exercises: people without chronic disease or injury (2015) and healthy adults (2017) in the reviews, 59 trained men and women on machines in 2019, and 13 trained men on one leg exercise in 2022.

A result from machine exercises or a leg extension does not describe free weight work, and the abstracts do not test it.

What the abstracts do not say

They do not recommend a tempo for any individual, compare speeds with other training variables, or report on beginners lifting free weights. The 2015 review notes a lack of controlled studies. The 2022 trial had 13 participants, and its authors describe the hypertrophy advantage as small and the adaptations as regional.

The bottom line

The 2015 meta-analysis reports similar hypertrophy for repetition durations from 0.5 to 8 seconds. The 2017 meta-analysis reports similar strength gains from fast and moderate-slow training, with a non-significant trend favouring fast at moderate intensities. The 2019 trial found no strength differences between three repetition durations in 10 weeks, and the 2022 trial found similar strength gains on fast and slow legs with a small difference in distal thigh thickness. These come from abstracts, from different outcomes and groups, and none covers dumbbells or kettlebells.

Sources

• Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis, Schoenfeld and colleagues, Sports Medicine, April 2015 (abstract, PubMed), read 3 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Effect of Movement Velocity During Resistance Training on Dynamic Muscular Strength: A Systematic Review and Meta-Analysis, Davies and colleagues, Sports Medicine, August 2017 (abstract, PubMed), read 3 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Neither repetition duration nor number of muscle actions affect strength increases, body composition, muscle size, or fasted blood glucose in trained males and females, Carlson and colleagues, Applied Physiology, Nutrition, and Metabolism, February 2019 (abstract, PubMed), read 3 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Does Varying Repetition Tempo in a Single-Joint Lower Body Exercise Augment Muscle Size and Strength in Resistance-Trained Men?, Pearson and colleagues, Journal of Strength and Conditioning Research, 2022 (abstract, PubMed), read 3 November 2026 (pubmed.ncbi.nlm.nih.gov)

Four published papers look at what happens to strength and muscle size when training stops and starts again. This guide reads their PubMed or PubMed Central abstracts, on 2 November 2026: a 2013 meta-analysis of training cessation, a 2011 trial in which 15 young men took a 3-week break, a 2024 randomised trial with a 10-week break, and a 2022 meta-analysis in older adults. Full texts were not used for the figures, so details beyond the abstracts are not covered. The papers say nothing about particular equipment, and this guide makes no claim about dumbbells or kettlebells. General information, not training advice.

What the largest review found about stopping

The 2013 paper by Bosquet and colleagues in the Scandinavian Journal of Medicine and Science in Sports searched seven databases and included 103 of 284 potential studies. It used training status, sex, age and the duration of cessation as moderators and reported standardised mean differences (SMD) with 95% confidence intervals:

• submaximal strength: SMD minus 0.62 (minus 0.80 to minus 0.45)
• maximal force: SMD minus 0.46 (minus 0.54 to minus 0.37)
• maximal power: SMD minus 0.20 (minus 0.28 to minus 0.13)

The abstract reports a dose-response relationship between the size of the effect and the duration of cessation, a larger effect in people over 65, and a larger effect on maximal force and maximal power in inactive people than in recreational athletes. Its conclusion is that resistance training cessation decreases all components of muscular strength, and that the size of the effect differs with training status, age and cessation duration. The abstract does not give a figure in weeks for when losses begin.

Two trials with breaks of 3 and 10 weeks

A 2011 trial by Ogasawara and colleagues, published in Clinical Physiology and Functional Imaging, divided 15 previously untrained young men into a continuous group, which did high-intensity bench press training for 15 weeks, and an interrupted group, which trained for 6 weeks, stopped for 3 weeks and resumed at week 10. The abstract reports no significant decreases in muscle cross-sectional area or one repetition maximum after the 3-week break, similar gains in muscle size after retraining to those after the initial block, and similar improvements in both groups after the 15-week period. The authors suggest that, compared with continuous training, 3-week detraining does not inhibit muscle adaptations.

A 2024 trial in the Scandinavian Journal of Medicine and Science in Sports randomised 55 healthy untrained participants, aged 32 plus or minus 5 years, to periodic or continuous training; 20 and 22 completed the study in the two groups. The periodic group did 10 weeks of twice-weekly supervised whole-body training, 10 weeks of detraining and a second 10-week block. The continuous group did 10 weeks without training, then 20 weeks of training. Both groups increased leg press and biceps curl 1RM, muscle size at two sites and countermovement jump height, with no differences between them. In the periodic group, those measures decreased during the 10 weeks of detraining. Over the first 5 weeks of retraining, the periodic group’s increases in leg press 1RM and muscle size at both sites were greater than the continuous group’s over its weeks 10 to 15. The authors suggest that trainees should not be too concerned about occasional short-term training breaks in their daily lives.

Longer gaps in older adults

A 2022 meta-analysis by Grgic in the International Journal of Environmental Research and Public Health pooled six studies with eight groups of older adults. Training interventions lasted 9 to 24 weeks and detraining lasted 12 to 52 weeks. It reports that muscle size rose after training and fell after training cessation. In subgroup analyses it reports no significant decrease in muscle size after 12 to 24 weeks of cessation and a significant decrease after 31 to 52 weeks. The author concludes that loss of muscle size might be related to the duration of detraining, and that future studies are needed to establish the time course.

Why these results should not be added together

The four papers measured different things in different people. The 2013 review looked at strength outcomes across many studies, including older people and athletes. The 2011 trial measured a bench press and muscle size in 15 young men after 3 weeks, and the 2024 trial measured leg and arm exercises in 55 untrained adults after 10 weeks. The 2022 review measured muscle size only, in older adults, over 12 to 52 weeks. A 3-week result from young men does not describe a 10-week or 52-week gap, and a result in older adults does not describe younger lifters. The 2011 and 2024 trials enrolled untrained participants, and their abstracts do not describe trained lifters returning after a break.

What the abstracts do not say

Nothing in the abstracts covers what to do during a break, how to restart, or what any individual should expect. They do not compare lifting with other activity during the break. Each reports results for groups, not for any one person.

The bottom line

The 2013 meta-analysis reports that stopping resistance training reduces strength, with the size of the effect related to how long training stopped. The 2011 trial found no significant loss in muscle size or 1RM after a 3-week break in 15 young men, and the 2024 trial found that measures fell during a 10-week break in untrained adults and recovered quickly on retraining. The 2022 meta-analysis in older adults reports a significant decrease in muscle size after 31 to 52 weeks of cessation and none that reached significance after 12 to 24 weeks. Because the samples, measures and break lengths differ, the papers are summarised separately here and not combined into one rule. The figures come from abstracts.

Sources

• Effect of training cessation on muscular performance: a meta-analysis, Bosquet and colleagues, Scandinavian Journal of Medicine and Science in Sports, 2013 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Effects of periodic and continued resistance training on muscle CSA and strength in previously untrained men, Ogasawara and colleagues, Clinical Physiology and Functional Imaging, 2011 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Does Taking a Break Matter? Adaptations in muscle strength and size between continuous and periodic resistance training, Scandinavian Journal of Medicine and Science in Sports, 2024 (abstract, PubMed), read 2 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Use It or Lose It? A meta-analysis on the effects of resistance training cessation (detraining) on muscle size in older adults, Grgic, International Journal of Environmental Research and Public Health, 28 October 2022 (abstract, PubMed Central), read 2 November 2026 (pmc.ncbi.nlm.nih.gov)

In one eight-week study of 21 trained men, a group that rested 3 minutes between sets gained more in 1RM squat and bench press than a group that rested 1 minute. Reviews of the wider literature add qualifications, and how they differ from that study is the subject of this guide. Only the PubMed abstracts of four papers were read, on 1 November 2026. Full texts were not read, so nothing beyond the abstracts is reported, and the figures below are the authors’ own.

The four papers at a glance

• Schoenfeld and colleagues, Journal of Strength and Conditioning Research, 2016: a controlled study in which 21 young resistance-trained men were randomly assigned to 1-minute or 3-minute rests, with all other training variables held constant.
• Grgic, Schoenfeld and colleagues, Sports Medicine, 2018: a systematic review of rest intervals and muscular strength, covering 23 studies and 491 participants (413 males and 78 females).
• Grgic and colleagues, European Journal of Sport Science, 2017: a systematic review of short (60 seconds or less) against long (more than 60 seconds) inter-set rests and muscle size, covering six studies.
• Singer and colleagues, Frontiers in Sports and Active Living, 2024: a systematic review with Bayesian meta-analysis of inter-set rest and muscle size, covering nine randomised studies and 19 measurements.

Strength: what the 2018 review concluded

The 2018 review starts from a gap: recommendations on rest for strength gains are largely inferred from studies of acute effects, and it is uncertain whether they carry over to long-term adaptation. Its aim was to gather the studies that measured chronic strength adaptations with different rest intervals.

Its conclusion has three parts. Robust gains in muscular strength can be achieved even with short rests of under 60 seconds. Longer rests of more than 2 minutes seem to be required to maximise strength gains in resistance-trained individuals. For untrained individuals, short to moderate rests of 60 to 120 seconds seem sufficient. The authors rated all included studies as good to moderate in methodological quality.

The 2016 controlled study points the same way for trained men. After eight weeks of three total-body workouts a week, each made up of 3 sets of 8 to 12 repetition maximum on 7 exercises, maximal strength in both the 1RM squat and bench press was significantly greater in the 3-minute group than in the 1-minute group.

Muscle size: a less settled picture

The 2017 review described the findings on short against long rests as equivocal, and concluded that both short and long rests may be useful for gaining muscle size. It reported that novel findings in trained participants, using measures sensitive enough to detect change, suggest a possible advantage for long rests, and it called for further research because few studies had similar designs.

In the 2016 study, muscle thickness was significantly greater in the 3-minute group in the anterior thigh, with a trend, at p = 0.06, in the triceps. Both groups improved local upper-body muscle endurance, and the difference between them was not significant.

The 2024 meta-analysis found substantial overlap between the effect sizes for short and longer rests, and substantial heterogeneity in results. For the arm and thigh, its central estimates tended to favour longer rests; for the whole body, the estimate was close to zero and marginally favoured shorter rests. The credible intervals reported in the abstract for the arm, thigh and whole body all span zero. The authors conclude that results suggest a small hypertrophic benefit to rests of more than 60 seconds, perhaps mediated by reductions in volume load, but that no appreciable difference was detected when resting more than 90 seconds between sets.

Reading “perhaps mediated by volume load”

The 2024 authors offer a possible reason rather than a finding. They say the small benefit of longer rests is perhaps mediated by reductions in volume load, and that this is consistent with evidence that detrimental effects on volume load tend to plateau beyond 90 seconds. A sub-analysis of end-point data found that training to failure, or stopping short of it, did not meaningfully change how rest length related to muscle size.

What the abstracts leave open

• The samples differ. The 2016 study involved young resistance-trained men; the 2018 review had 413 male and 78 female participants and gives separate conclusions for trained and untrained individuals; the 2024 analysis covers healthy adults.
• The measures differ. Strength reviews and muscle-size reviews use different outcomes, and the 2024 paper pools arm, thigh and whole-body measurements that do not all point the same way.
• Equipment is not the focus. The abstracts read do not describe training with adjustable dumbbells or kettlebells, and the 2016 study tested strength with the squat and bench press.
• Pooled figures hide spread. The 2024 authors flag substantial heterogeneity, and the 2017 authors flag too few comparable studies.

The bottom line

For strength, the 2018 review concludes that short rests can still produce robust gains, while rests of more than 2 minutes seem to be needed to maximise gains in resistance-trained people. For muscle size, the 2017 review calls both short and long rests useful, and the 2024 meta-analysis reports a small benefit above 60 seconds with no clear extra benefit above 90 seconds. The abstracts do not address kettlebell or adjustable dumbbell training specifically, and the authors themselves describe the muscle-size evidence as varied.

Sources

• Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men, Schoenfeld and colleagues, Journal of Strength and Conditioning Research, 2016, abstract, read 1 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Effects of rest interval duration in resistance training on measures of muscular strength: a systematic review, Sports Medicine, 2018, abstract, read 1 November 2026 (pubmed.ncbi.nlm.nih.gov)
• The effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy: a systematic review, European Journal of Sport Science, 2017, abstract, read 1 November 2026 (pubmed.ncbi.nlm.nih.gov)
• Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy, Frontiers in Sports and Active Living, 2024, abstract, read 1 November 2026 (pubmed.ncbi.nlm.nih.gov)

Aching muscles a day or two after a hard session are a familiar part of lifting, and a whole market of recovery methods has grown around them. Two published meta-analyses, a large 2018 review of recovery techniques and a 2019 review of foam rolling, put numbers on what has actually been tested. Both were read on 28 October 2026. They deal with healthy adults and exercise in general, not with dumbbells and kettlebells specifically.

Four terms the review keeps using

• DOMS: delayed onset muscle soreness.
• Perceived fatigue: a rating of fatigue as the participants perceive it.
• Muscle damage marker: in this review, blood levels of creatine kinase (CK).
• Inflammatory markers: blood levels of C-reactive protein (CRP) and interleukin-6 (IL-6).

The 2018 review, by Dupuy and colleagues, set out to evaluate how recovery techniques affect DOMS, perceived fatigue, muscle damage and inflammatory markers after exercise.

What was pooled

From 1,693 potentially relevant publications spanning 1958 to 2017, 99 studies met the inclusion criteria. Of these, 80 measured DOMS, with 1,188 participants and 106 experimental groups. Studies had to involve healthy adults aged over 18 and under 65. The authors found no effect of exercise characteristics on how well a recovery method worked, and the only population difference was a greater effect on DOMS in males than in females.

Which methods lowered soreness, and which did not

Active recovery, massage, compression garments, immersion, contrast water therapy and cryotherapy produced a small to large decrease in DOMS, with effect sizes (Hedges’ g) between −2.26 and −0.40; the review reports no change for the other methods. Stretching and electrostimulation were among those, with the authors stating that they found no significant influence of either on DOMS or fatigue. On stretching, the authors say their overall result confirmed that it had no positive impact on DOMS.

Of the techniques that did lower soreness, the authors concluded that massage seems to be the most effective method for reducing DOMS and perceived fatigue. They describe compression garments and immersion as having a significant positive effect on the same measures but a less pronounced one.

Blood markers moved too. Across the pooled studies the authors observed an overall moderate decrease in creatine kinase and small decreases in interleukin-6 and C-reactive protein, and they identified massage and cold exposure as the most powerful techniques for reducing inflammation. These are laboratory measures. The paper itself notes that there can be a mismatch between blood-based measures of inflammation or soreness and the recovery of short-term muscular performance.

Foam rolling: a separate review

A 2019 meta-analysis by Wiewelhove and colleagues examined foam rolling in 21 studies, 14 of them with rolling before exercise (pre-rolling) and 7 with rolling after (post-rolling). Post-rolling slightly attenuated exercise-induced decreases in sprint performance (+3.1%, g = 0.34) and strength performance (+3.9%, g = 0.21), and reduced muscle pain perception (+6.0%, g = 0.47).

The authors summarised the overall effects of foam rolling on performance and recovery as rather minor and partly negligible, though relevant in some cases, such as increasing sprint performance and flexibility or reducing muscle pain sensation. They wrote that the evidence seems to justify the widespread use of foam rolling as a warm-up activity rather than a recovery tool.

The limits the authors list

For the 2018 review, the authors state that only one recovery session was examined, and they say it is important to know whether similar outcomes follow when a technique is used on a regular basis. They also note that the placebo effect could not be eliminated, given the practical difficulty of blinding participants to recovery methods, and that publication and language restriction bias may have inflated estimates. Performance would also have been an important outcome, they say, but it was not evaluated.

The foam rolling authors list their own limits: most included studies had small samples, none could blind participants, methods varied widely (including the pressure applied), and the studies recruited both elite athletes and recreationally active or untrained people. Their analysis covers articles published before January 2018.

What this means for a home lifter

• The studies pooled results across many kinds of exercise, so they say little about soreness after a particular dumbbell or kettlebell session.
• Neither review reports whether using any recovery method changes muscle growth over months.
• Stretching, on the 2018 review’s result, did not lower soreness.
• Pain that is sharp, severe or unusual is outside what these reviews cover, and a health professional is the person to ask.

The bottom line

The 2018 meta-analysis of 99 studies found that several methods lowered soreness after a single exercise session, with massage seen as the most effective by its authors, while stretching did not. The 2019 foam rolling meta-analysis found small effects on muscle pain, and its authors thought the evidence supported foam rolling more as a warm-up than as recovery. Both sets of authors point to limits such as small samples, no blinding and a single recovery session.

Sources

• An evidence-based approach for choosing post-exercise recovery techniques to reduce markers of muscle damage, soreness, fatigue, and inflammation: a systematic review with meta-analysis, Frontiers in Physiology, 2018, read 28 October 2026 (pmc.ncbi.nlm.nih.gov)
• A meta-analysis of the effects of foam rolling on performance and recovery, Frontiers in Physiology, 2019, read 28 October 2026 (pmc.ncbi.nlm.nih.gov)

Dumbbell bench press or barbell bench press is a common choice when setting up home training. Laboratory studies have compared the two directly, usually with a Smith machine as a third option. The four studies below are small, mostly of trained men, and were read as published PubMed abstracts on 28 October 2026. They report what happened in the lab, not which exercise is better for any individual.

The four studies in one table

Study	Who took part	What was compared	Stated result
Tillaar and Sæterbakken, 2012	11 men with at least a year of bench press training	One-repetition maximum (1RM) in barbell, Smith machine and dumbbell presses	1RM was highest with the barbell, then the Smith machine, then dumbbells
Farias and colleagues, 2017	19 trained men	Four sets to a 10-repetition maximum with each press, 2 minutes rest	More total repetitions with dumbbells; different muscle activity patterns
Christian and colleagues, 2023	20 people (10 men, 10 women) with at least a year of training	Dumbbell and barbell presses at incline, flat and decline angles	Muscle activity differed by angle and by muscle
Sæterbakken and colleagues, 2020	35 resistance-trained men	Ten weeks of training with Smith machine, dumbbells or a barbell on a Swiss ball	Changes carried over to the barbell bench press

The load: what the 1RM figures show

In the 2012 study, every participant was tested for a 1RM in all three chest-press exercises. The group reached 106.4 kg (standard deviation 15.5) with the free barbell, 103.6 kg (14.8) with the Smith machine and 89.5 kg (13.7) with dumbbells, as reported in the abstract, which does not say how the dumbbell figure was counted. Muscle activity, measured with electromyography (EMG), also differed between the exercises. The authors had expected that more freedom of movement would lengthen the “sticking region”, the weakest part of the lift, but the differences did not follow that order. They concluded that it is possible to choose a chest-press exercise to train a particular muscle more than the others.

More repetitions, different muscles busy

The 2017 study had 19 trained men perform each press for four sets with a 10-repetition-maximum load, resting 2 minutes between sets, and then do a triceps extension. Total repetitions were significantly higher with dumbbells (31.2) than with the barbell (27.8). The dumbbell press produced significantly greater pectoralis major activity than the barbell press, while the Smith machine produced greater anterior deltoid activity than either. The Smith machine and barbell presses produced greater triceps brachii activity than dumbbells, and dumbbells produced greater biceps brachii activity than the Smith machine and barbell. The authors reported that the choice of press also changed repetition performance and muscle activity in the triceps extension that followed.

Does the angle change the answer?

The 2023 study asked 20 people, aged 24 on average, to find a 1RM for flat dumbbell and barbell bench presses, then lift at 70% of that 1RM at incline, flat and decline positions. Anterior deltoid activation was significantly higher during the incline barbell press than during the decline barbell and decline dumbbell presses. Pectoralis major activation was significantly lower during the incline dumbbell press than the decline dumbbell press. The authors suggested that stability demands and shoulder width may explain some differences, and that sensor placement could have affected the pectoralis readings during the decline press. They also inferred that larger amounts of body fat in the female participants caused irregularities in the pectoralis data. Those explanations are the authors’ own, not tested findings.

After ten weeks of training

The 2020 trial randomised 35 resistance-trained men, averaging 4.2 years of training, to a ten-week programme with two chest-press sessions a week using a Smith machine, dumbbells, or a barbell on a Swiss ball. Everyone was tested on a 6-repetition maximum in both their own exercise and the barbell bench press. All three groups lifted more slowly and spent longer in the sticking and post-sticking regions at the end, and regardless of which exercise was trained, no differences were observed in vertical displacement or in muscle activity across the lifting regions. The authors read this as transfer to the untrained barbell press, and noted that improved strength altered the sticking region in resistance-trained men.

What these abstracts do not say

• None reports muscle size, so none shows which press builds more muscle.
• Samples are small, and three of the four include only men.
• Participants were trained lifters; beginners were not the focus.
• EMG records electrical activity during a lift, which is different from long-term results.
• The abstracts give no safety comparison between the exercises.

The bottom line

Across these four small studies, barbell presses allowed higher 1RM loads, dumbbells allowed more repetitions in one set of tests, and the muscles with the highest activity varied by exercise and angle. The authors of the 2012 study suggested choosing a press to emphasise a muscle, and the 2020 trial found carry-over from the trained exercise to the barbell press. Anyone changing their training should follow qualified coaching advice.

Sources

• The sticking region in three chest-press exercises with increasing degrees of freedom, Journal of Strength and Conditioning Research, 2012 (abstract on PubMed), read 28 October 2026 (pubmed.ncbi.nlm.nih.gov)
• Maximal strength performance and muscle activation for the bench press and triceps extension exercises adopting dumbbell, barbell, and machine modalities over multiple sets, Journal of Strength and Conditioning Research, 2017 (abstract on PubMed), read 28 October 2026 (pubmed.ncbi.nlm.nih.gov)
• Analysis of the activation of upper-extremity muscles during various chest press modalities, Journal of Strength and Conditioning Research, 2023 (abstract on PubMed), read 28 October 2026 (pubmed.ncbi.nlm.nih.gov)
• The effects of ten weeks resistance training on sticking region in chest-press exercises, PLoS One, 2020 (abstract on PubMed), read 28 October 2026 (pubmed.ncbi.nlm.nih.gov)

In the 2026 American College of Sports Medicine (ACSM) overview of 137 systematic reviews covering more than 30,000 participants, voluntary strength was enhanced by lifting heavier loads (80% or more of one-repetition maximum), through a complete range of motion, for 2 to 3 sets, at the beginning of training sessions, and on 2 or more sessions a week. Range of motion is one item in that list, and three smaller reviews look at it directly. This guide sets them out. It is general information for healthy adults, not medical advice, and none of the abstracts read is specific to dumbbells or kettlebells.

What the ACSM overview did and did not find

The ACSM position stand is an overview of reviews. It included systematic reviews of randomised trials in healthy adults aged 18 or over who completed resistance training for at least 6 weeks, compared with no exercise or with an alternative resistance training programme. Its summary says that few prescription variables affected the primary adaptations. Beyond the strength variables above, it says training to momentary muscle fatigue, equipment type, exercise complexity, set structure, time under tension, blood flow restriction and periodization did not consistently affect training outcomes.

Two observations on the abstract’s wording: complete range of motion is listed for strength, and not for hypertrophy, power or endurance; and the abstract gives no definition of “complete”.

Three reviews side by side

Review	Studies	What the abstract reports
Schoenfeld and Grgic, 2020 (SAGE Open Medicine)	6 studies, 135 participants (127 men and 8 women)	Full range of motion had beneficial effects on lower-body hypertrophy compared with partial. Research on the upper limbs was limited and conflicting. No study had examined the trunk.
Pallarés and colleagues, 2021 (Scandinavian Journal of Medicine & Science in Sports)	16 studies	Full range of motion produced significantly greater adaptations than partial for muscle strength (effect size 0.56) and lower-limb hypertrophy (0.88). Functional performance favoured full range (0.44) but not significantly. No significant difference was found for muscle thickness, pennation angle and fascicle length (0.28).
Kassiano and colleagues, 2023 (Journal of Strength and Conditioning Research)	11 studies	Full range, and partial range in the initial part of the movement, gave greater hypertrophy of the rectus femoris, vastus lateralis, biceps brachii and brachialis (distal sites) than partial range in the final part. One comparison went the other way: partial range in the middle part gave greater triceps brachii hypertrophy than full range (effect size 1.21).

What the longer-muscle-length finding says

The Kassiano review concluded that when training at a longer muscle length, through either partial or full range of motion, some muscles such as the quadriceps femoris, biceps brachii and triceps brachii tend to experience optimal growth. It added that partial range in the initial part of the excursion, in combination with full range training, should be considered when prescribing hypertrophy-oriented programmes. The Schoenfeld and Grgic review separately noted that some evidence indicates the response to range of motion may be muscle-specific, a hypothesis it said warrants further study.

Reading the evidence with care

• The reviews pool studies of resistance training in general. The abstracts do not say how many used dumbbells or kettlebells.
• The Schoenfeld and Grgic review had 8 women among its 135 participants.
• Pallarés and colleagues describe a lack of consensus and high controversy about the most effective range of motion. Their significant results were for strength and lower-limb hypertrophy.
• The effect sizes in the table come from different reviews, outcomes and comparisons, and are listed as each abstract reports them.

What NHS instructions look like

The NHS “Strength exercises” page (page last reviewed 28 February 2024) says not to worry if you have not done much for a while, and it does not use the phrase “range of motion”. Its mini-squat instruction says to bend the knees slowly as far as is comfortable. Its biceps curl, done with a pair of light weights, says to bend the arms slowly until the weight reaches the shoulder and then to lower slowly. The page says to build up slowly and to try these exercises at least twice a week.

For the weekly target, the NHS guidelines for adults aged 19 to 64 (last reviewed 22 May 2024) say to do strengthening activities that work all the major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms) on at least 2 days a week, to the point where you need a short rest before repeating the activity. Examples include lifting weights, working with resistance bands and exercises that use your own body weight. The page advises speaking to your GP first if you have not exercised for some time, or if you have medical conditions or concerns. For choosing a load, see the guide to how to choose the right dumbbell weight; for exercises by muscle group, see dumbbell exercises for every muscle group.

The bottom line

The ACSM overview lists a complete range of motion among the variables that enhanced voluntary strength. Two reviews report an advantage for full range over partial in lower-body outcomes, and the Kassiano review found full range and initial-part partial range both ahead of final-part partial range at several sites. Research on the upper limbs was described as limited and conflicting, and one comparison favoured partial range for triceps growth. None of the abstracts is specific to dumbbells or kettlebells.

Sources

• American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews, 2026 (europepmc.org)
• Effects of range of motion on muscle development during resistance training interventions: A systematic review, SAGE Open Medicine, 2020 (pubmed.ncbi.nlm.nih.gov)
• Effects of range of motion on resistance training adaptations: A systematic review and meta-analysis, Scandinavian Journal of Medicine & Science in Sports, 2021 (pubmed.ncbi.nlm.nih.gov)
• Which ROMs Lead to Rome? A Systematic Review of the Effects of Range of Motion on Muscle Hypertrophy, Journal of Strength and Conditioning Research, 2023 (pubmed.ncbi.nlm.nih.gov)
• Strength exercises, NHS, page last reviewed 28 February 2024 (nhs.uk)
• Physical activity guidelines for adults aged 19 to 64, NHS, page last reviewed 22 May 2024 (nhs.uk)

Illustration: a lifter has just put down the dumbbells after a session and has about five minutes before leaving. What do the sources say about spending them stretching? Two NHS pages describe stretching routines, and two research papers look at what stretching does. This guide sets them side by side. It is general information for healthy adults, not medical advice, and none of the sources is specific to dumbbell or kettlebell training. The NHS pages were read on 27 October 2026.

What the NHS cool-down contains

The NHS page “How to stretch after exercising” (page last reviewed 16 March 2026) describes its routine as a way to cool down after a workout, to gradually relax, improve flexibility and slow the heart rate. It says the gentle stretches should take about 5 minutes, and that you can spend more time if you feel the need.

The routine has five stretches, each held for 15 to 20 seconds: buttock, hamstring, inner thigh, calf and thigh. All five work the lower body. The page says that if you have an injury, a medical condition or are pregnant, you may need to make changes to some stretches, and to talk to a physiotherapist or healthcare professional about which ones are right for you.

A second NHS routine, with different holds

The NHS “Flexibility exercises” page (page last reviewed 20 November 2023) is a different routine, which says not to worry if you have not done much exercise for a while. It lists neck rotation, a neck stretch, a sideways bend and a calf stretch, with instructions such as moving “as far as is comfortable”, and says to build up slowly. It says to try to do the exercises at least twice a week and to combine them with its sitting, balance and strength routines.

The hold times differ from the cool-down page: 5 seconds for the neck stretch and 2 seconds for the sideways bend, against 15 to 20 seconds for each cool-down stretch. The pages describe different routines, and each figure is given as it appears on its own page.

What the Cochrane review tested

A Cochrane review published in 2011, with searches to early 2010, asked whether stretching before or after exercise affects delayed-onset muscle soreness. It included 12 randomised or quasi-randomised studies. One was a large field trial with 2,377 participants, 1,220 of whom were allocated to stretching. The other 11 were small, with 10 to 30 participants in the stretch condition. All were at moderate or high risk of bias, and the quality of the evidence was low to moderate.

• After exercise only: the pooled estimate was a reduction in soreness one day later of about one point on a 100-point scale (4 studies; the 95% confidence interval ran from a 6.88-point reduction to a 4.79-point increase).
• Before and after, in the large trial: peak soreness over a week was about four points lower on the same scale, which the authors call statistically significant but very small.

The authors concluded that stretching before, after, or before and after exercise does not produce clinically important reductions in delayed-onset muscle soreness in healthy adults.

What 20 experts agreed in 2025

A Delphi consensus statement in the Journal of Sport and Health Science used a panel of 20 experts who reviewed existing systematic reviews, with at least 80% agreement required. The panel agreed that chronic and acute stretching improves range of motion (although alternatives exist) and reduces muscle stiffness, which may not always be desirable. It agreed that chronic stretching may promote vascular health, but that more research is warranted.

It also agreed that stretch training does not contribute substantively to muscle growth, does not serve as an all-encompassing injury prevention strategy, does not improve posture, and does not acutely enhance post-exercise recovery. A consensus statement is expert agreement based on reviews, not a new trial.

Does stretching count towards the weekly target?

The NHS guidelines for adults aged 19 to 64 (last reviewed 22 May 2024) say adults should aim to do strengthening activities that work all the major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms) on at least 2 days a week. Effort matters: the page says to do them to the point where you need a short rest before repeating the activity. Its examples include lifting weights, working with resistance bands, exercises that use your own body weight, yoga, pilates and tai chi. Stretching routines are not among the examples. The guide to what counts as muscle-strengthening activity compares the NHS and CMO lists in full.

The bottom line

The NHS cool-down routine takes about 5 minutes and holds each of five lower-body stretches for 15 to 20 seconds. The 2011 Cochrane review found no clinically important reduction in delayed-onset muscle soreness from stretching in healthy adults, and the 2025 Delphi panel agreed that stretching improves range of motion but does not acutely enhance post-exercise recovery. Anyone with an injury, a medical condition or pregnancy is pointed by the NHS to a physiotherapist or healthcare professional. For the other end of the session, see the guide to warming up for dumbbell and kettlebell sessions.

Sources

• How to stretch after exercising, NHS, page last reviewed 16 March 2026 (nhs.uk)
• Flexibility exercises, NHS, page last reviewed 20 November 2023 (nhs.uk)
• Physical activity guidelines for adults aged 19 to 64, NHS, page last reviewed 22 May 2024 (nhs.uk)
• Stretching to prevent or reduce muscle soreness after exercise, Cochrane Database of Systematic Reviews, 2011 (pubmed.ncbi.nlm.nih.gov)
• Practical recommendations on stretching exercise: A Delphi consensus statement of international research experts, Journal of Sport and Health Science, 2025 (pubmed.ncbi.nlm.nih.gov)