Barefoot and Minimalist Shoes: What the Research Actually Supports

Minimalist and barefoot-style shoes do something real. Randomised trials show they make the small muscles of the foot measurably bigger and stronger, and they change how the foot meets the ground. What they have not been shown to do is prevent running injuries. The 2022 Cochrane review of running footwear found no reliable injury advantage for any shoe type, and the best-known transition trials found more bone marrow oedema on MRI in runners who switched. The honest summary: treat minimalist footwear as a slow-acting foot-strengthening tool, not as injury insurance.

What minimalist footwear demonstrably does

It grows the small muscles of the foot

This is the strongest claim in the field, and it rests on randomised trials rather than observation. In Ridge and colleagues, Medicine & Science in Sports & Exercise 2019;51(1):104-113, 57 runners were randomly assigned for eight weeks to walking in provided minimalist shoes with a weekly-increasing daily step count, a progressive foot-strengthening exercise programme at least five days a week, or a control group. Everyone kept their pre-study running mileage unchanged. Size was measured by ultrasound and strength by custom dynamometers at weeks 0, 4 and 8. Both rose significantly in the two intervention groups and did not change in controls. The researchers concluded that walking in minimalist shoes was as effective as dedicated foot exercises.

A separate randomised trial from the same laboratory — Johnson and colleagues, International Journal of Sports Medicine 2016;37(2):154-158, 37 runners randomised to Vibram FiveFingers or traditional shoes for ten weeks — reported a 10.6% increase in abductor hallucis cross-sectional area relative to control (p = 0.01). None of the other muscles measured changed significantly. The effect is real but narrower than the marketing implies.

Over a longer horizon, Chen and colleagues, Clinical Biomechanics 2016;36:8-13 put 20 habitually shod runners through a six-month minimalist transition against 18 matched controls, with MRI before and after. Foot muscle volume increased (p < 0.01, Cohen’s d = 0.54), concentrated in the forefoot (d = 0.64) rather than the rearfoot (p = 0.10, d = 0.30), and how much participants actually wore the shoes correlated with muscle change (r = 0.51, p = 0.02).

Pooling this literature tempers it. Peters-Dickie and colleagues, Clinical Biomechanics 2025;122:106417, a systematic review and meta-analysis of 28 randomised trials and 1,399 participants, found greater strength of toes two to five with minimalist shoes (standardised mean difference, 95% CI 0.02 to 0.76) but conflicting results for muscle size. The authors rated the certainty low to very low, citing the small number of studies and high risk of bias, and declared no competing interests.

It changes how you land — but not always in the direction people expect

The foundational paper is Lieberman and colleagues, Nature 2010;463(7280):531-535. Comparing habitually barefoot with habitually shod endurance runners, the researchers reported that barefoot runners often land on the fore-foot and less often on the heel, while shod runners mostly rear-foot strike — a pattern the elevated, cushioned heel makes possible. Even on hard surfaces, barefoot fore-foot strikers generated smaller collision forces than shod rear-foot strikers, driven by a more plantarflexed foot at landing and more ankle compliance. Two flags. The paper’s own conclusion is hedged: such gaits may protect against impact-related injury. And per its acknowledgements, the work was partially funded by a gift from Vibram USA, a minimalist footwear manufacturer.

Crucially, a shoe is not a foot strike. Willy and Davis, Medicine & Science in Sports & Exercise 2014;46(2):318-323 tested 14 male rearfoot-striking runners who had never worn a minimalist shoe, running ten minutes on an instrumented treadmill in both a minimalist and a standard shoe. Step length and step rate did not change. Vertical impact peak (p = 0.017) and average vertical loading rate (p < 0.001) were greater in the minimalist shoe, and both rose further over the accommodation period. Put a habitual heel-striker in a thin shoe and change nothing else, and loading goes up, not down.

It alters sensory input to the foot

Thinner, more flexible soles change what the sole of the foot feels, which is routinely marketed as better proprioception and balance. The measured results are mixed. In Zech and colleagues, European Journal of Sport Science 2015;15(4):279-285, a randomised crossover study of 35 distance runners on a force plate, the barefoot condition produced significantly greater postural sway velocity than every footwear condition, minimalist shoes included (p < 0.001). And in a six-week randomised agility-training study of 30 adults (Paquette and colleagues, Research Quarterly for Exercise and Sport 2017;88(1):44-51), balance and change-of-direction scores improved equally in the barefoot, minimal and traditional groups. Sensory input changes; a balance advantage has not been established.

What the evidence does not establish

The claim that minimalist shoes reduce injuries is the one most often made and the one with the weakest support. The best available synthesis is Relph and colleagues, Cochrane Database of Systematic Reviews 2022;8(8):CD013368, which pooled 12 randomised and quasi-randomised trials totalling 11,240 participants, with follow-up of six to 26 weeks. For the comparison that matters here — neutral/cushioned versus minimalist shoes, five studies and 766 participants — cushioned shoes made little or no difference to the number of runners sustaining a lower-limb injury, with a risk ratio of 0.77 (95% CI 0.59 to 1.01), rated low-certainty evidence. Note the direction: the point estimate marginally favours the cushioned shoe, and the interval crosses no effect. The review concluded that most evidence shows no reduction in lower-limb running injuries when comparing shoe types, at very low to low certainty. Most review authors declared no conflicts; one had contributed to a sports-equipment manufacturer’s think tank on an expenses-only basis, and one had previously run research funded by ASICS.

The single most informative individual trial is Fuller and colleagues, American Journal of Sports Medicine 2017;45(5):1162-1170: 61 trained habitual rearfoot-striking runners randomised to minimalist or conventional shoes and progressed gradually over 26 weeks. Sixteen of 31 were injured in minimalist shoes versus 11 of 30 in conventional shoes — a hazard ratio of 1.64, but with an interval spanning no effect (95% CI 0.63 to 4.27, p = 0.31), so the trial could not settle the overall question. What it did detect were interactions. Weekly running pain was greater in minimalist shoes, reaching a clinically meaningful difference above about 35 km per week, and risk scaled with body mass: at 85.7 kg the hazard ratio was 2.00 (95% CI 1.10 to 3.66, p = 0.02).

Nor has anyone shown that bigger foot muscles translate into fewer injuries. That step — from cross-sectional area to real-world injury rates — remains an assumption, not a finding.

The transition itself is where the documented harm sits

Ridge and colleagues, Medicine & Science in Sports & Exercise 2013;45(7):1363-1368 gave 36 experienced recreational runners MRI scans before and after a ten-week period. Seventeen stayed in traditional shoes; 19 gradually transitioned to Vibram FiveFingers. Bone marrow oedema was scored 0 to 4, where 4 represents oedema in more than half a bone’s length and corresponds to a stress fracture. Pre-training scans did not differ. Afterwards, 10 of the 19 minimalist-group runners showed an increase in at least one bone, significantly more than controls (p = 0.009). The companion report from the same cohort (Johnson 2016, above) put the control figure at one runner, and found that those who developed oedema — primarily women — had significantly smaller baseline size in every muscle assessed (p ≤ 0.05).

The detail that should stick: this was already a gradual ten-week transition, and it still produced an MRI signal. Ten weeks is not slow enough.

A staged transition consistent with the trial protocols

To capture the documented benefit (stronger feet) while avoiding the documented harm (bone stress), the research points toward a progression measured in months and led by walking. This is general education, not medical advice, and no substitute for a clinician who can examine your feet.

1. Months 1-2 — walking only. The Ridge 2019 protocol that produced measurable muscle growth involved no running at all: participants simply increased their daily step count in the shoes each week for eight weeks. Start indoors and on errands.
2. Month 3 — one short run, if you run. A single easy run per week in the minimalist shoe, a small fraction of weekly volume, on a forgiving surface. Everything else stays in your usual shoes.
3. Months 4-6 — creep the volume. Add minimalist mileage in small weekly increments rather than jumps, and keep conventional shoes for long and fast sessions.
4. Respect a ceiling. In the Fuller trial, pain became clinically meaningful above roughly 35 km per week in minimalist shoes. Higher-mileage runners have less headroom, not more.
5. Strengthen in parallel. Ridge 2019 found foot-strengthening exercises produced equivalent gains — a stimulus that does not involve absorbing ground reaction force.
6. Know the stop signs. Pinpoint tenderness on a bone, pain across the top of the foot, shin pain, or any ache still present the next morning means stop progressing and get assessed. Bone stress injuries are far easier to manage early.
7. Do not deliberately change foot strike at the same time. The Willy and Davis data show a thin shoe does not automatically produce a forefoot landing, and changing footwear and gait together makes it impossible to tell which is causing a problem.

Who should be cautious or avoid this entirely

Diabetes with peripheral neuropathy is the clearest contraindication in the guideline literature. The 2023 International Working Group on the Diabetic Foot guideline on preventing foot ulcers recommends educating at-risk people not to walk without suitable foot protection, and prescribing properly fitting, accommodative therapeutic footwear with a demonstrated plantar-pressure-relieving effect for those at moderate-to-high risk. Minimalist footwear does the opposite of pressure relief, and a foot with reduced protective sensation cannot report the pain that would otherwise stop you.

A prior metatarsal or navicular stress fracture, a rigid deformity, or any active foot complaint warrants assessment before adding an unfamiliar load pattern. Higher body mass and high weekly mileage were the two interaction terms that reached significance in the Fuller trial. And small baseline foot muscle size flagged the runners who went on to develop bone marrow oedema in the Johnson analysis — an argument for building strength through exercise before spending real time in minimalist shoes.

Limitations of this evidence base

These caveats are substantial enough that no strong recommendation is defensible in either direction.

• The trials are small and short. Sample sizes of 14 to 61 and durations of eight to 26 weeks are typical. Only the pooled Cochrane dataset reaches five figures, and most of that comes from military footwear-prescription trials, not minimalist-shoe comparisons.
• Most outcomes are surrogates. Muscle cross-sectional area, muscle volume, loading rate and postural sway are proxies. The trials powered for muscle size are not powered for injury.
• Blinding is impossible. The Cochrane authors flagged this as a reason for downgrading certainty: runners always know which shoe they were given, which contaminates self-reported pain and injury.
• Minimalist is not a standardised category. Vibram FiveFingers, a racing flat and a wide-toe-box zero-drop trainer all carry the label and load the foot very differently. The Cochrane review called for a consensus definition of running shoe design precisely because of this.
• Certainty ratings are low. Both the Cochrane review and the 2025 meta-analysis graded their evidence low to very low — a statement about how likely these estimates are to change with better trials. The answer is: quite likely.
• Funding and conflicts are not always visible. The Nature paper discloses partial Vibram USA funding; the 2025 meta-analysis authors declared none; the Cochrane team declared two minor industry links. Several of the smaller trials carry no funding statement in the indexed record at all.
• The populations studied are narrow. Overwhelmingly young, healthy, trained recreational runners — very little data on older adults, complete beginners, or people with the conditions that make foot health most consequential.

The bottom line

Minimalist footwear has one well-supported effect: worn consistently, it strengthens the muscles of the foot — and the trial that showed this most cleanly did it with walking, not running. What no trial has shown is that any of this prevents injury, and the transition carries a documented, MRI-visible bone stress signal even when described as gradual. If the trade still looks worthwhile, the evidence favours going slower than feels necessary, leading with walking, and building foot strength deliberately rather than hoping the shoes will do it for you.