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Reference topic 7: The Foot That Forgot the Ground

Barefoot shoes and foot strength: what the evidence says

ProbableEvidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.50 sources5 graded recommendationsTopic hub: MovementTopic hub: Strength and bone

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The children came from a rural primary school in Kenya's Rift Valley, and none had ever worn shoes. Daniel Lieberman's team filmed 16 of them running down a track of hard dirt. Two-thirds of their footfalls landed on the ball of the foot, and only 12% on the heel. Pupils from an urban school, running in their shoes, struck heel first 97% of the time.1

On force plates, sensors that measure how hard a foot lands, American volunteers showed why that might matter. "The average runner strikes the ground 600 times per kilometre, making runners prone to repetitive stress injuries," the team wrote. A heel strike delivers a sudden spike of force, about 1.5 to 3 times body weight. Habitually barefoot runners landing on the forefoot produced an impact peak about three times lower. The shoe barely lowered the spike; it slowed its rise nearly sevenfold, and that is what makes a heel strike comfortable.1 Whether it makes one harmless is a separate question.

Mismatch card

The system

The foot, a sensing, spring-loaded base for walking, running and balance.

What it expects

Bare or thinly shod feet on varied ground, working the arch and toes daily.

What it gets

Cushioned, arch-supported, toe-sprung shoes on flat floors from early childhood.

What happens in the gap

Less ground feel, softened impacts of unknown cost, likely weaker foot muscles and, in some studies, flatter arches; in old age, weak toes and poor balance are linked to falls.

The handrail

Balance and strength training (●●●); gradual minimal-shoe walking or foot exercises (●●○)

Strength of evidence

●●○ Trials show foot strength returns with use, but the links from lifelong shoe-wearing to flat feet, injuries and falls rest on cross-sectional and retrospective data.

What this topic covers

  • ·A Foot Older Than Shoes
  • ·The Sole as a Sense Organ
  • ·Heels, Forefeet and a Tidy Story
  • ·The Rarámuri
  • ·Feet That Weaken and Recover
  • ·The Fall

The practical version is in the book: Chapter 3, The Body That Walks.

The handrail

Each recommendation carries the strength of the evidence behind it. How the grades work.

  1. Train balance and strength, especially after 60

    StrongEvidence grade: Strong. Multiple randomized controlled trials, or consistent large cohort studies with a well-understood mechanism.

    At least three days a week, practice single-leg stands, stepping, sit-to-stand or Tai Chi, plus resistance work; progress for at least 12 weeks and keep going. Programs that challenge balance for more than three hours a week work best; walking alone is not proven to prevent falls.31324546

  2. Give your feet work, gradually

    ProbableEvidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.

    Evidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials. for strength·Evidence grade: Emerging. Early, small, animal-only, or actively contested. for balance

    Walk in flat, flexible shoes with room for the toes, starting with about 30 minutes a day and building wear time over about 16 weeks. Or do foot exercises (toe curls, arch doming) at least five days a week. Gains appear within eight weeks and seem to level off by about six months.232433 With knee osteoarthritis, supportive shoes won the one head-to-head trial (●●○).42

  3. Runners: take months, not weeks

    ProbableEvidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.

    Do not change a comfortable heel strike just because it is one. Heavier runners, and those running over 35 km (22 miles) a week, fared worse in minimalist shoes in one trial. Pain focused on one foot bone means stop and get it checked.374738

  4. At home after 65, wear shoes

    ProbableEvidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.

    Choose low heels and firm, slip-resistant soles indoors and out, not socks or slippers. Practice barefoot balance only on a clear floor beside something solid to hold.2948

  5. Safety

    StrongEvidence grade: Strong. Multiple randomized controlled trials, or consistent large cohort studies with a well-understood mechanism.

    Up to half of people with diabetes have peripheral neuropathy. With diabetes, numb feet, poor leg circulation or past foot ulcers, do not go barefoot or switch to minimal shoes without your clinician, and check your feet daily.4950

The skeptic's corner

The case against this topic, from the research itself.

The barefoot boom promised fewer running injuries, and the trials have not borne that out. A Cochrane review of 12 trials found that "most evidence demonstrates no reduction in lower-limb running injuries in adults when comparing different types of running shoes", though most of it was of low or very low certainty.34 About 40% of runners are injured during follow-up,35 and injury rates do not seem to have shifted despite decades of changing shoe design.36 Another review found only limited, backward-looking evidence linking a non-heel strike to fewer injuries, and would not recommend changing strike for an uninjured heel-striker.37

Switching can hurt. When 19 runners moved gradually to toe-shoes over 10 weeks, 10 showed increased bone marrow edema, fluid in the bone visible on scans, in at least one foot bone. Runners in their usual shoes showed it less often, and the authors urged a transition "very slowly and gradually".38 Vibram, denying the allegations, agreed to pay $3.75 million to settle class actions alleging it had falsely claimed its FiveFingers toe-shoes could reduce injury and strengthen muscles.39

Money runs through the science. Vibram USA helped fund the Nature study, whose authors declared competing financial interests,1 and later minimal-shoe studies had ties to two other barefoot-shoe makers.4033 That does not make the findings wrong, but readers should know it.

Shoes also earn their keep. Wearing them is associated with lower odds of hookworm and other infections that enter through the feet (Topic 20).41 And in a trial of 164 people with knee osteoarthritis (wear-and-tear arthritis), stable supportive shoes eased walking pain more than flat flexible ones, with fewer adverse events, against the researchers' own hypothesis.42

Grounding, the claim that bare skin on soil lets electrons flow in and calm inflammation, is weaker still. A review of its claimed benefits was written by contractors for EarthFx, the company sponsoring grounding research, and a key human study it cites grounded just four people.43 A later trial by one of the same authors relied on self-reports from 16 massage therapists.44 No independent, adequately sized trial comparing grounding with a sham (fake) connection appears to have been published. On current evidence grounding is unsupported (Topic 38).

Terms this topic defines

Related topics

Sources cited above

  1. 1.Lieberman, D.E., Venkadesan, M., Werbel, W.A., Daoud, A.I., et al. (2010). "Foot strike patterns and collision forces in habitually barefoot versus shod runners." Nature, 463(7280), 531-535. https://doi.org/10.1038/nature08723 (school in South Nandi District, in the Kalenjin-speaking Rift Valley; the team confirmed with teachers and by watching that the children had never worn shoes; eight girls and eight boys averaging 13.5 years, each running at preferred speed on a 20-25 m track filmed at 500 frames a second; 22% of their footfalls landed flat; the shod comparison pupils attended an urban school in Eldoret; the heel-strike impact spike is about 1.5-3 times body weight within 50 milliseconds; barefoot forefoot strikes peaked at 0.58 body weights against 1.74-1.89 for heel strikes with or without shoes; the shoe slowed the spike nearly sevenfold compared with a barefoot heel strike)
  2. 2.Nature (2010). Cover, Nature, 463(7280), 28 January 2010: "TREAD SOFTLY: How we ran in comfort before we started wearing shoes."
  3. 34.Relph, N., Greaves, H., Armstrong, R., Prior, T.D., et al. (2022). "Running shoes for preventing lower limb running injuries in adults." Cochrane Database of Systematic Reviews, 8, CD013368. https://doi.org/10.1002/14651858.CD013368.pub2 (11,240 participants)
  4. 35.Kakouris, N., Yener, N., and Fong, D.T.P. (2021). "A systematic review of running-related musculoskeletal injuries in runners." Journal of Sport and Health Science, 10(5), 513-522. https://doi.org/10.1016/j.jshs.2021.04.001
  5. 36.Nigg, B.M., Baltich, J., Hoerzer, S., and Enders, H. (2015). "Running shoes and running injuries: mythbusting and a proposal for two new paradigms: 'preferred movement path' and 'comfort filter'." British Journal of Sports Medicine, 49(20), 1290-1294. https://doi.org/10.1136/bjsports-2015-095054 (Benno Nigg and colleagues: "there does not seem to be a secular trend in running injury rates")
  6. 37.Anderson, L.M., Bonanno, D.R., Hart, H.F., and Barton, C.J. (2020). "What are the benefits and risks associated with changing foot strike pattern during running? A systematic review and meta-analysis of injury, running economy, and biomechanics." Sports Medicine, 50(5), 885-917. https://doi.org/10.1007/s40279-019-01238-y
  7. 38.Ridge, S.T., Johnson, A.W., Mitchell, U.H., Hunter, I., et al. (2013). "Foot bone marrow edema after a 10-wk transition to minimalist running shoes." Medicine and Science in Sports and Exercise, 45(7), 1363-1368. https://doi.org/10.1249/MSS.0b013e3182874769
  8. 39.GlobeNewswire (2014). Vibram FiveFingers Class Action Settlement Provides Consumer Refunds (14 July 2014; lead case Bezdek v. Vibram USA Inc., No. 1:12-cv-10513, D. Mass.). https://www.globenewswire.com/news-release/2014/07/14/650392/10089064/en/Vibram-FiveFingers-Class-Action-Settlement-Provides-Consumer-Refunds.html
  9. 40.Cudejko, T., Gardiner, J., Akpan, A., and D'Août, K. (2020). "Minimal shoes improve stability and mobility in persons with a history of falls." Scientific Reports, 10, 21755. https://doi.org/10.1038/s41598-020-78862-6 (three authors declare a mutual grant ownership with Vivobarefoot Ltd.).
  10. 33.Futrell, E., and Chevan, J. (2026). "Effects of long-term minimal footwear use on fall-risk and fall incidence in older adults." Gerontology, 72(4), 245-257. https://doi.org/10.1159/000550264 (part of the footwear was donated by Xero Shoes; funded by the US Centers for Disease Control and Prevention).
  11. 41.Tomczyk, S., Deribe, K., Brooker, S.J., Clark, H., et al. (2014). "Association between footwear use and neglected tropical diseases: a systematic review and meta-analysis." PLoS Neglected Tropical Diseases, 8(11), e3285. https://doi.org/10.1371/journal.pntd.0003285 (53 observational studies, mostly of poor quality).
  12. 42.Paterson, K.L., Bennell, K.L., Campbell, P.K., Metcalf, B.R., et al. (2021). "The effect of flat flexible versus stable supportive shoes on knee osteoarthritis symptoms: a randomized trial." Annals of Internal Medicine, 174(4), 462-471. https://doi.org/10.7326/M20-6321
  13. 43.Oschman, J.L., Chevalier, G., and Brown, R. (2015). "The effects of grounding (earthing) on inflammation, the immune response, wound healing, and prevention and treatment of chronic inflammatory and autoimmune diseases." Journal of Inflammation Research, 8, 83-96. https://doi.org/10.2147/JIR.S69656 (disclosure: Chevalier and Oschman are contractors for EarthFx Inc. and own a small percentage of its shares; Brown is also a contractor. The muscle-soreness study cited is Brown, D., Chevalier, G., and Hill, M. (2010). "Pilot study on the effect of grounding on delayed-onset muscle soreness." Journal of Alternative and Complementary Medicine, 16(3), 265-273. https://doi.org/10.1089/acm.2009.0399, with eight subjects, four grounded). (two of the contractors own small stakes in EarthFx; the grounded study had eight subjects)
  14. 44.Chevalier, G., Patel, S., Weiss, L., Chopra, D., et al. (2019). "The effects of grounding (earthing) on bodyworkers' pain and overall quality of life: a randomized controlled trial." Explore, 15(3), 181-190. https://doi.org/10.1016/j.explore.2018.10.001 (the therapists reported their own pain and mood)
  15. 31.Sherrington, C., Fairhall, N.J., Wallbank, G.K., Tiedemann, A., et al. (2019). "Exercise for preventing falls in older people living in the community." Cochrane Database of Systematic Reviews, 1, CD012424. https://doi.org/10.1002/14651858.CD012424.pub2 (108 trials with 23,407 people averaging 76 years)
  16. 32.Sherrington, C., Michaleff, Z.A., Fairhall, N., Paul, S.S., et al. (2017). "Exercise to prevent falls in older adults: an updated systematic review and meta-analysis." British Journal of Sports Medicine, 51(24), 1750-1758. https://doi.org/10.1136/bjsports-2016-096547
  17. 45.Bull, F.C., Al-Ansari, S.S., Biddle, S., Borodulin, K., et al. (2020). "World Health Organization 2020 guidelines on physical activity and sedentary behaviour." British Journal of Sports Medicine, 54(24), 1451-1462. https://doi.org/10.1136/bjsports-2020-102955
  18. 46.Montero-Odasso, M., van der Velde, N., Martin, F.C., Petrovic, M., et al. (2022). "World guidelines for falls prevention and management for older adults: a global initiative." Age and Ageing, 51(9), afac205. https://doi.org/10.1093/ageing/afac205
  19. 23.Ridge, S.T., Olsen, M.T., Bruening, D.A., Jurgensmeier, K., et al. (2019). "Walking in minimalist shoes is effective for strengthening foot muscles." Medicine and Science in Sports and Exercise, 51(1), 104-113. https://doi.org/10.1249/MSS.0000000000001751 (2019 trial; 57 runners randomized)
  20. 24.Curtis, R., Willems, C., Paoletti, P., and D'Août, K. (2021). "Daily activity in minimal footwear increases foot strength." Scientific Reports, 11, 18648. https://doi.org/10.1038/s41598-021-98070-0 (2021 study; 22 volunteers; people who had worn such shoes for two and a half years were no stronger than the six-month group)
  21. 47.Fuller, J.T., Thewlis, D., Buckley, J.D., Brown, N.A., et al. (2017). "Body mass and weekly training distance influence the pain and injuries experienced by runners using minimalist shoes: a randomized controlled trial." American Journal of Sports Medicine, 45(5), 1162-1170. https://doi.org/10.1177/0363546516682497
  22. 29.Koepsell, T.D., Wolf, M.E., Buchner, D.M., Kukull, W.A., et al. (2004). "Footwear style and risk of falls in older adults." Journal of the American Geriatrics Society, 52(9), 1495-1501. https://doi.org/10.1111/j.1532-5415.2004.52412.x (327 people aged 65 and older who fell, and 327 matched controls)
  23. 48.Menant, J.C., Steele, J.R., Menz, H.B., Munro, B.J., et al. (2008). "Optimizing footwear for older people at risk of falls." Journal of Rehabilitation Research and Development, 45(8), 1167-1181. https://pubmed.ncbi.nlm.nih.gov/19235118/
  24. 49.Bus, S.A., Sacco, I.C.N., Monteiro-Soares, M., Raspovic, A., et al. (2024). "Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2023 update)." Diabetes/Metabolism Research and Reviews, 40(3), e3651. https://doi.org/10.1002/dmrr.3651
  25. 50.National Institute of Diabetes and Digestive and Kidney Diseases (2018). What Is Diabetic Neuropathy? https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/nerve-damage-diabetic-neuropathies/what-is-diabetic-neuropathy

This topic carries 50 notes in the research manuscript; the 25 above are those behind the material on this page. Full source register.