Same Lifts, Different Plan? Strength Training for Women and Men

Walk into most gyms and you'll still see a split: men at the squat rack, women with light dumbbells and resistance bands. Fitness marketing often reinforces it, with "toning" programmes for women and "mass" programmes for men. Female triathletes in particular often hear that they need lighter weights, more repetitions, or different exercises altogether.

This article looks at what happens when researchers give men and women the same strength programme and measure the results. It covers three meta-analyses, a pair of trials in cyclists, and research on fatigue, then turns that into practical guidance for triathletes. TriForward's "Two Sessions a Week" and "The Minimum Effective Dose" cover how much lifting a triathlete needs. This article asks whether the plan itself should differ by sex.

Absolute and relative: why the question gets confusing

On average, men are stronger than women and have more muscle, particularly in the upper body. That is not in dispute. The question that matters for training is different: when men and women follow the same programme, do they improve by the same proportion?

That distinction matters because the same result can be described in two ways:

• Absolute change is the raw amount gained, such as kilograms added to a lift or square centimetres of muscle.
• Relative change is the gain as a percentage of where you started.

Inference: if a man starts with a 100 kg squat and a woman with a 60 kg squat, and both improve by 20%, the man gains 20 kg and the woman 12 kg. The absolute gains differ, but both responded equally well to the training. Most of the apparent disagreements in this research come from mixing these two measures.

The 2020 meta-analysis

The study most often cited on this question is a 2020 meta-analysis by Brandon Roberts, Greg Nuckols and James Krieger in the Journal of Strength and Conditioning Research. Its protocol was registered in advance. They included studies in which young to middle-aged men and women followed the same resistance training programme, and they compared the responses.

Their main findings:

• Muscle growth: 12 outcomes from 10 studies showed no significant sex difference (effect size 0.07, P = 0.31).
• Lower-body strength: 23 outcomes from 23 studies showed no significant difference (effect size −0.21, P = 0.20).
• Upper-body strength: 19 outcomes from 17 studies showed a significant effect favouring women in relative terms (effect size −0.60, P = 0.002). This was the only significant difference.

The authors concluded that men and women gain similar amounts of muscle and lower-body strength from the same training, and that women may have a greater capacity to improve relative upper-body strength, at least when untrained. They suggested this could reflect neural or motor-learning factors, or simply the short length of the studies, and called for more research.

Two limits are worth keeping in mind. The heterogeneity for strength outcomes was high (I² above 70), meaning the studies varied a lot. And the participants were mostly untrained, so the larger upper-body gains in women may partly reflect a lower starting point rather than a sex difference in how muscle adapts.

The 2025 Bayesian meta-analysis

A 2025 meta-analysis by Milo Refalo and colleagues, including Greg Nuckols, in PeerJ looked specifically at muscle size. They screened 2,720 studies and included 29 in healthy adults aged 18 to 45.

• Absolute muscle growth slightly favoured men, with a standardised difference of 0.19 (95% highest density interval 0.11 to 0.28).
• Relative muscle growth was similar, with a difference of 0.69% (95% interval −1.50% to 2.88%), an interval that comfortably includes zero.
• The absolute advantage for men appeared in the upper body, not the lower body.
• Training experience didn't change the results, although the authors noted that very well-trained people need more study.

The authors concluded that women appear to have a similar capacity for muscle growth as men, especially when measured as a percentage of their starting size. Inference: for a female triathlete, this suggests that heavy lifting will build muscle at roughly the same relative rate as it would for a male training partner.

What happens after 50

Many triathletes are in their 40s, 50s and beyond, so the 2021 meta-analysis by Matthew Jones and colleagues in Sports Medicine is particularly relevant. It focused on adults over 50 doing identical resistance training programmes. They included 30 studies with 41 comparisons and 1,410 participants, 651 men and 759 women. Study quality was rated moderate.

In relative terms:

• Lower-body strength gains favoured women (g = −0.21, 95% CI −0.33 to −0.10).
• Upper-body strength gains showed no significant difference.
• Muscle size gains showed no significant difference.

In absolute terms, men gained more:

• Upper-body strength: g = 0.48.
• Lower-body strength: g = 0.33.
• Muscle size: g = 0.45.

The authors noted that whether sex differences appear depends heavily on whether results are expressed in absolute or relative terms. Inference: for an older female triathlete, the message is encouraging. Lifting works at least as well, in percentage terms, as it does for men of the same age. TriForward's "Strength Training After 50" covers the specific case for power training with age.

Evidence from cyclists

The meta-analyses above mostly involve people who aren't endurance athletes. A 2021 review by Olav Vikmoen and Bent Rønnestad in the Journal of Functional Morphology and Kinesiology brought together their own Norwegian trials of heavy strength training in cyclists, carried out separately in men and women.

In both sets of trials, cyclists added 11 to 12 weeks of heavy lower-body strength training, twice a week, to their normal endurance training. The programmes used four lower-body exercises, three sets each, progressing from 10-repetition maximum loads towards 4-repetition maximum. Control groups did endurance training only.

The results were similar between sexes, and in some measures women improved more:

• Lower-body strength: +38.6% in women and +26.0% in men (P = 0.08).
• Quadriceps size: +7.4% in women and +4.6% in men (P = 0.11).
• 40-minute average power: +6.4% in women and +6.0% in men.
• Power output in a 5-minute test after 3 hours of riding: +7.0% in women and +7.2% in men.
• VO2max: no change in either sex compared with controls.
• Cycling economy in short submaximal bouts: improved only in women.

The authors were careful about the limits. Men and women were tested in separate studies rather than compared directly. The men were at a higher performance level and trained more hours per week (9.9 compared with 5.1). There were no data on elite female cyclists. They concluded that both sexes can improve cycling performance by adding strength training, but that the evidence isn't yet strong enough to make sex-specific recommendations.

TriForward's "Heavy Lifting for Bike Power" covers what this research means for FTP and time-trial performance.

Fatigue: a real difference, but task-specific

One area where men and women do appear to differ is fatigability. A 2014 review by Sandra Hunter in Acta Physiologica concluded that women are usually less fatigable than men during similar-intensity isometric contractions. The size of the difference depends on the task, including the type, intensity and speed of contraction, the muscle group and the environment.

Proposed mechanisms include differences in muscle fibre type, blood flow and energy metabolism, and in how the nervous system activates muscles.

Inference: in practice, a woman may be able to complete more repetitions at a given percentage of her maximum than a man. This doesn't mean women need lighter loads or different exercises. It does mean that prescribing sets by percentage of one-repetition maximum may work slightly differently between sexes. Using repetitions in reserve, stopping a set with one to three good repetitions left, adjusts for this automatically.

Do women need different exercises?

The short answer from the evidence is no. In all of the trials pooled in these meta-analyses, men and women did the same programme and both improved. None of the reviews found evidence that women respond better to lighter, higher-repetition training or to a different set of exercises.

What can reasonably differ is the starting point:

• Upper-body strength is often lower relative to the lower body in women, so press-ups, pull-ups or rows may need to start from an easier variation.
• Experience with free weights may differ. Many women triathletes have spent less time in the weights area and benefit from a few weeks of technique-focused sessions.
• Confidence and environment matter. A crowded free-weights area can be off-putting, and that is a practical barrier rather than a physiological one.

None of these call for a different plan. They call for the same plan with a sensible starting level.

For triathletes, the upper-body point has a practical side. Swimming relies heavily on the shoulders, back and arms, and many female age-groupers come to the sport with relatively little upper-body strength. Inference: the 2020 meta-analysis suggests this is where untrained women may see some of their fastest relative progress, so it is a poor area to skip. TriForward's "Dryland Strength That Transfers to the Water" covers which upper-body exercises are most relevant to swimming, and "Swimmer's Shoulder in Triathletes" covers how to build shoulder load gradually.

Where sex and life stage genuinely matter

Some factors do change strength training for women, and a few for men. They are about health and life stage rather than the training response itself.

• Bone health. Bone loss accelerates around menopause, and swimming and cycling do little for bone. TriForward's "Lifting for Bone" and "Menopause and the Triathlete" cover this in detail.
• Pregnancy and the postpartum period. None of the trials in this article studied these groups. Return-to-lifting decisions need individual advice.
• The menstrual cycle. Many women are told to train according to their cycle phase. TriForward's "Cycle Syncing Your Strength Sessions" covers what the evidence actually supports.
• Energy availability. Low energy availability impairs adaptation in both women and men. TriForward's "Under-Fuelled, Not Undertrained" covers it.

Putting it into practice

The suggestions below are inference from the research above, not a tested programme for triathletes:

1. Use the same core lifts. Squats, deadlifts or hip hinges, lunges or split squats, calf raises, a pressing movement and a pulling movement suit both sexes.
2. Lift heavy enough to matter. The cyclist trials progressed from 10-repetition maximum loads towards 4-repetition maximum loads. A woman triathlete has no evidence-based reason to stay with light weights.
3. Lift twice a week. Both the cyclist trials and TriForward's "Two Sessions a Week" support this as a realistic dose alongside endurance training.
4. Prescribe by effort, not just percentage. Use repetitions in reserve to allow for differences in fatigability.
5. Start upper-body work at the right level. Use easier variations, such as incline press-ups or assisted pull-ups, and progress them.
6. Track relative progress. Compare yourself with your own starting point, not with your training partner's absolute numbers.

A triathlon scenario

The following example is illustrative, not drawn from a study. A couple in their late 30s train together for a 70.3. He has lifted on and off for years; she has never lifted and has been told she should use light weights so she doesn't "bulk up" before the race.

Based on the evidence:

• They can follow the same programme, with her loads and her upper-body variations set to her starting level.
• She can expect to progress quickly, in percentage terms possibly faster than him, because she is starting from a lower base and the trials suggest relative gains are at least similar.
• Muscle gains will be modest during a season of endurance training. In the cyclist trials, women added 7.4% quadriceps size over 11 to 12 weeks while improving their 40-minute power.
• Both can treat the season the same way, building strength in the winter and keeping a smaller dose through race season, as TriForward's "The Off-Season Strength Block" discusses.

Common mistakes

• Choosing loads by sex rather than by ability. Light pink dumbbells and heavy barbells are a marketing distinction, not a training principle.
• Comparing absolute numbers. A smaller absolute gain can still be an equal or better relative improvement.
• Assuming women won't gain muscle, or that men will gain far more. Relative gains are broadly similar.
• Skipping the upper body. Women made relatively larger upper-body gains in the 2020 meta-analysis, and swimming benefits from upper-body strength.
• Copying a percentage-based plan without adjusting. Use repetitions in reserve.

What we don't know

• How trained female athletes respond over longer periods. Most studies lasted a few months in untrained participants.
• Whether men and women differ when endurance training is added. The cyclist data come from separate studies, and there is no direct comparison in triathletes.
• Why women make larger relative upper-body gains, and whether that holds beyond the first few months.
• How hormonal contraception, pregnancy and menopause interact with strength gains, since these are rarely recorded in the trials.

References

• Roberts BM, Nuckols G, Krieger JW. Sex differences in resistance training: a systematic review and meta-analysis. Journal of Strength and Conditioning Research, 2020;34(5):1448–1460. doi:10.1519/JSC.0000000000003521
• Refalo MC, Nuckols G, Galpin AJ, Gallagher IJ, Hamilton DL, Fyfe JJ. Sex differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta-analysis. PeerJ, 2025;13:e19042. doi:10.7717/peerj.19042
• Jones MD, Wewege MA, Hackett DA, Keogh JWL, Hagstrom AD. Sex differences in adaptations in muscle strength and size following resistance training in older adults: a systematic review and meta-analysis. Sports Medicine, 2021;51(3):503–517. doi:10.1007/s40279-020-01388-4
• Vikmoen O, Rønnestad BR. A comparison of the effect of strength training on cycling performance between men and women. Journal of Functional Morphology and Kinesiology, 2021;6(1):29. doi:10.3390/jfmk6010029
• Hunter SK. Sex differences in human fatigability: mechanisms and insight to physiological responses. Acta Physiologica, 2014;210(4):768–789. doi:10.1111/apha.12234