Barefoot and minimalist running
Evidence: limited
Running barefoot or in minimalist shoes changes foot-strike mechanics but has no proven benefit for injury prevention or performance; the marketed claims run well ahead of the data. An abrupt switch is a common way to get injured.
Barefoot running, and its near-equivalent in thin “minimalist” shoes, was popularised as a more natural, injury-proof way to run. The evidence does not bear out the strong claims. A systematic review found no conclusive evidence that barefoot or minimalist running prevents injury or enhances performance (barefoot running review).
What it does change
Running without cushioning reliably shifts most people from a heel strike toward a forefoot or midfoot strike, with lower vertical loading rates at impact and a higher cadence (barefoot running review). These are real biomechanical changes, and they shift load from one place to another: less impact transient and less work at the knee, but more demand on the calf, Achilles and foot. Whether that trade reduces injury overall is exactly what the evidence cannot show; injury-rate comparisons come out roughly even once mileage is accounted for, and foot-strike pattern itself has not been shown to determine injury or economy.
The transition is the danger
The clearest finding is a caution. Switching abruptly to barefoot or minimalist running loads the calf, Achilles and the bones of the foot in ways the body is not conditioned for, and raises the risk of injury, including metatarsal bone-stress injuries, during the change. This is the tissue-adaptation lag in action: the muscles and bones need months to adapt to the new loading, and enthusiasm outruns them. Any transition has to be very gradual, over months, not weeks.
The volume argument against it
The deeper case against barefoot running follows from the central fact of the sport: the main way to get better at running is to run more, so the consistent volume that builds fitness is the thing to protect above almost all else. Anything that lets a runner accumulate that volume with less injury is therefore net good, which is the real argument for cushioned shoes: they reduce the per-stride load and let most runners train more, more often, with fewer breakdowns. Barefoot running pushes the other way. By stripping cushioning and concentrating load on the calf, Achilles and foot, it lowers the volume most people can sustain before something gives, especially during the long transition. Even if its mechanics were advantageous, a method that caps how much you can safely train is working against the main driver of improvement.
A reasonable position
Barefoot or minimalist running is a legitimate personal preference and a useful occasional drill for foot and lower-leg strength, but not an evidence-based injury cure or performance upgrade. Most runners do well in comfortable conventional shoes chosen by feel. Anyone drawn to minimalism should transition slowly and judge it by their own response, the same individual-test principle that applies to everything else (individual variation).