Your toes do more work than you give them credit for, and most of what is written about them is either a shrug or an overstatement. This is an attempt at neither. Here is what the research actually shows about what toes do, what modern shoes do to them, and what it is reasonable to do about it.
What toes are for
At the end of every step, as your heel lifts and your weight rolls forward, the only parts of your foot still on the ground are the ball of the foot and the toes. In that moment the ground is pushing up on your toes hard enough to bend them backward at the joints where they meet the foot — the metatarsophalangeal joints. The small muscles inside your foot fire to resist that, stabilising the joints and supporting the arch so the foot can act as a firm lever to push off from.1
That happens several thousand times a day. It is the main thing toes do, and it is the thing shoes change.
What your shoes do about it
Look at almost any shoe from the side and the toe curves upward off the ground. That curve is called a toe spring, and it is so common that almost nobody had studied it until 2020.
Researchers at Harvard, Chemnitz and Buffalo had 13 people walk on a treadmill barefoot and in four custom sandals with toe springs from 10 to 40 degrees. The more the toe curved upward, the less work the muscles around the toe joints had to do. The toe spring was doing part of their job for them.1
A separate comparison of habitually barefoot or minimally-shod people with people who wear conventional shoes found that foot strength and stiffness tracked with footwear use.2
Put those together and you have a plausible story: shoes take work away from the toe muscles, muscles that do less work get weaker, and weaker toe muscles have consequences for how the foot behaves under load.
What that story has not proven
The toe spring study measured muscle work during walking. It did not follow anyone over years to see whether their muscles actually weakened. The researchers are clear that this is what they hypothesise, not what they measured, and that any link to conditions like plantar fasciitis needs further testing.1
You will also read that weak toes cause knee pain, hip strain, back problems, poor posture, or a weak core. We have looked for research supporting those cascades and have not found it. The foot is connected to the rest of the body, but "connected" is not the same as "causes", and we are not going to write it as if it were.
What is reasonable to do
- Spend time barefoot at home. Free, and it gives the toe muscles the work the shoe was doing for them.
- Buy shoes with room in the toe box. A wide toe box costs nothing in function.
- Train the toes directly. A 2023 meta-analysis of 13 randomized trials found that training the small muscles of the foot improved balance, strength, arch behaviour and self-reported foot function — though not pain.3
Where this goes next
Feet do different jobs in different sports, and the research does not say the same thing about all of them. Rather than flatten it into one article, we have written it up by activity, with every figure sourced and every limit stated.
- For runners — the year-long randomized trial in which runners who trained their foot muscles were 2.4 times less likely to get injured, and what it doesn't prove.
- For climbers — hallux valgus at 53% in long-time climbers, and why the shoes come first.
- For dancers — what ballet builds in the foot, and the direction it leaves out.
- For older adults — toe grip strength predicts falls better than hand grip, and it is the part most fall-prevention programs skip.
- What toe stretching actually does — the trial in which wearing a spacer alone changed nothing, and adding the movement changed everything measured.
Toe-Rx is the tool we make for the third item on the list above. It holds the toes open and gives them something to close against, five to ten minutes at a time, sitting down. How to use it is here. Whether it is right for you depends on what you do with your feet — which is what the pages above are for.
*These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
References
- Sichting F, Holowka NB, Hansen OB, Lieberman DE. Effect of the upward curvature of toe springs on walking biomechanics in humans. Scientific Reports. 2020;10(1):14643. doi:10.1038/s41598-020-71247-9. PMID: 32943665. Read it
13 participants, walking. Measured muscle work, not muscle strength over time. The weakening consequence is the authors' hypothesis and they say so. - Holowka NB, Wallace IJ, Lieberman DE. Foot strength and stiffness are related to footwear use in a comparison of minimally- vs. conventionally-shod populations. Scientific Reports. 2018. Read it
Cross-sectional comparison of populations. Shows association with footwear use, not cause. - Jaffri AH, Koldenhoven R, Saliba S, Hertel J. Evidence for intrinsic foot muscle training in improving foot function: a systematic review and meta-analysis. Journal of Athletic Training. 2023;58(11–12):941–951. doi:10.4085/1062-6050-0162.22. PMID: 35724360. Read it
13 trials pooled, general population. Pain did not significantly improve.
