Why barefoot
26 bones, 33 joints and more than 100 muscles, tendons and ligaments in each foot. Here is what researchers measured when feet got room to work, and how to switch at your own pace.
Inside every foot
Each foot is a small machine that adjusts to the ground with every step. A stiff, padded, narrow shoe takes over much of that work. A barefoot shoe hands it back to the foot.
What the research measured
Independent research teams measured feet before and after people switched to minimal shoes. None of them tested 4.bare shoes: they tested what minimal footwear does in general.
Adults who wore minimal shoes in daily life for six months increased their toe-flexor strength by 57.4% on average. The group that stayed in conventional shoes did not change. People who had already worn minimal shoes for years were about as strong as the six-month group.1
Participants wore Vivobarefoot shoes. Funding: Future Footwear Foundation and KASK & Conservatorium; the authors declare no competing interests.
57 runners were split into three groups. After eight weeks, foot muscle size and strength rose significantly in the group that simply walked in minimal shoes, and just as much in the group doing foot exercises. The control group did not change.2
65 adults over 65 were randomly assigned to minimal shoes or their usual shoes. The minimal-shoe group improved on a standard balance test at 16 weeks and again after one year; the control group did not. The study did not find a significant difference in falls.8
Change on the Mini-BESTest, a 28-point clinical balance test.
A 2025 systematic review of seven studies with 213 participants points the same way, and also notes that most studies so far are small and short.3
Room for your toes
Over a century ago, doctors noticed that feet which never wore shoes are widest at the toes. Later studies of people who grew up barefoot describe wider forefeet and toes that sit further apart.56
Most shoes do the opposite. They narrow towards a point, so the toes have to squeeze together to fit. The 4.bare sole keeps its full width across the whole toe area, so your toes can lie flat and spread.
Feel the ground
Thick foam and a stiff sole mute what your foot feels. A thin, flexible sole lets the ground through, so your foot can react by itself instead of relying on padding.
How you land
Harvard researchers measured the force of each landing. Runners who landed on the front of a bare foot hit the ground with 0.58 body weights, about three times less than heel strikers in running shoes. Heel strikers without shoes landed hardest of all: how you land matters more than what is under you.4
The study measured forces, not injuries. It was co-funded by Vibram USA, and the authors declared competing financial interests. A new way of landing takes weeks to learn: see How to switch.
Hear it from the experts
Three independent videos on what barefoot shoes can do, who they suit, and why the switch should be slow.
Nature Video · Harvard biologist Daniel Lieberman on how barefoot runners land.
Harvard University · Harvard researchers on walking barefoot and what calluses do for the feet.
Dr. Dave Candy, physical therapist · Who barefoot shoes suit, who they do not, and how to switch safely.
Independent videos by the presenters named. They are not connected to 4.bare and do not endorse our shoes. Nothing loads from YouTube until you press play; then YouTube's privacy terms apply.
How to switch
Barefoot shoes move work from the shoe to your feet, calves and Achilles tendons. That takes time to build, and the first weeks matter most. Every expert says the same thing: start small.
10 to 20 minutes around the house or garden, 3 to 4 times a week. Getting used to it, not a workout.
Add 5 to 10 minutes at a time, no more than about 10% a week. Keep your usual shoes for long or tiring days.
Errands, walks, a day at work. Add simple foot work: calf raises, standing on one leg, spreading your toes.
Wear them as much as feels good. If you run, start again with short, easy runs and build up just as slowly.
The 24-hour rule: check how your feet and calves feel the next day before you add more. Sore? Stay at the same level until it passes. Pain that does not go away is a reason to see a podiatrist.
Honest about the science
4.bare shoes do not treat, cure or prevent any condition. If you have foot pain, diabetes or a diagnosed foot condition, talk to a podiatrist before you switch.
The studies here tested minimal footwear in general, not 4.bare shoes. They report group averages; your own feet may respond differently.
Every number on this page links to the original study below, with the funder named where the study names one.
Sneakers in cotton or leather and sandals in three models, all on the Extra Wide sole.
Why barefoot
26 bones, 33 joints and more than 100 muscles, tendons and ligaments in each foot. Here is what researchers measured when feet got room to work, and how to switch at your own pace.
Inside every foot
Each foot is a small machine that adjusts to the ground with every step. A stiff, padded, narrow shoe takes over much of that work. A barefoot shoe hands it back to the foot.
What the research measured
Independent research teams measured feet before and after people switched to minimal shoes. None of them tested 4.bare shoes: they tested what minimal footwear does in general.
Adults who wore minimal shoes in daily life for six months increased their toe-flexor strength by 57.4% on average. The group that stayed in conventional shoes did not change. People who had already worn minimal shoes for years were about as strong as the six-month group.1
Participants wore Vivobarefoot shoes. Funding: Future Footwear Foundation and KASK & Conservatorium; the authors declare no competing interests.
57 runners were split into three groups. After eight weeks, foot muscle size and strength rose significantly in the group that simply walked in minimal shoes, and just as much in the group doing foot exercises. The control group did not change.2
65 adults over 65 were randomly assigned to minimal shoes or their usual shoes. The minimal-shoe group improved on a standard balance test at 16 weeks and again after one year; the control group did not. The study did not find a significant difference in falls.8
Change on the Mini-BESTest, a 28-point clinical balance test.
A 2025 systematic review of seven studies with 213 participants points the same way, and also notes that most studies so far are small and short.3
Room for your toes
Over a century ago, doctors noticed that feet which never wore shoes are widest at the toes. Later studies of people who grew up barefoot describe wider forefeet and toes that sit further apart.56
Most shoes do the opposite. They narrow towards a point, so the toes have to squeeze together to fit. The 4.bare sole keeps its full width across the whole toe area, so your toes can lie flat and spread.
Feel the ground
Thick foam and a stiff sole mute what your foot feels. A thin, flexible sole lets the ground through, so your foot can react by itself instead of relying on padding.
How you land
Harvard researchers measured the force of each landing. Runners who landed on the front of a bare foot hit the ground with 0.58 body weights, about three times less than heel strikers in running shoes. Heel strikers without shoes landed hardest of all: how you land matters more than what is under you.4
The study measured forces, not injuries. It was co-funded by Vibram USA, and the authors declared competing financial interests. A new way of landing takes weeks to learn: see How to switch.
Hear it from the experts
Three independent videos on what barefoot shoes can do, who they suit, and why the switch should be slow.
Nature Video · Harvard biologist Daniel Lieberman on how barefoot runners land.
Harvard University · Harvard researchers on walking barefoot and what calluses do for the feet.
Dr. Dave Candy, physical therapist · Who barefoot shoes suit, who they do not, and how to switch safely.
Independent videos by the presenters named. They are not connected to 4.bare and do not endorse our shoes. Nothing loads from YouTube until you press play; then YouTube's privacy terms apply.
How to switch
Barefoot shoes move work from the shoe to your feet, calves and Achilles tendons. That takes time to build, and the first weeks matter most. Every expert says the same thing: start small.
10 to 20 minutes around the house or garden, 3 to 4 times a week. Getting used to it, not a workout.
Add 5 to 10 minutes at a time, no more than about 10% a week. Keep your usual shoes for long or tiring days.
Errands, walks, a day at work. Add simple foot work: calf raises, standing on one leg, spreading your toes.
Wear them as much as feels good. If you run, start again with short, easy runs and build up just as slowly.
The 24-hour rule: check how your feet and calves feel the next day before you add more. Sore? Stay at the same level until it passes. Pain that does not go away is a reason to see a podiatrist.
Honest about the science
4.bare shoes do not treat, cure or prevent any condition. If you have foot pain, diabetes or a diagnosed foot condition, talk to a podiatrist before you switch.
The studies here tested minimal footwear in general, not 4.bare shoes. They report group averages; your own feet may respond differently.
Every number on this page links to the original study below, with the funder named where the study names one.
Sneakers in cotton or leather and sandals in three models, all on the Extra Wide sole.