Taboga & Kram 2019, the effect of curves on distance-running performance

PeerJ modelling study of how running on curves slows distance runners. Negotiating a bend requires extra centripetal force, raising the average axial force the leg must apply and so the metabolic cost, which slows the achievable speed. The penalty grows as the curve radius tightens and as speed rises: a tight indoor track (17.5 m radius) is slower than a standard outdoor track (36.8 m radius), which is slower than a straight course. The effect is meaningful at elite speeds on tight indoor bends but negligible for gentle road curves and for recreational paces.