Running in highly cushioned shoes increases leg stiffness andimpact loading (2018)

This study tested how highly cushioned “maximalist” running shoes change impact forces and spring-like leg mechanics compared with conventional shoes. Twelve healthy male heel-strike runners completed 3D gait trials at 10.0 and 14.5 km/h wearing a Hoka Conquest (maximalist) and Brooks Ghost 6 (conventional). At the faster speed, the maximalist shoe produced a 10.7% higher vertical ground reaction force impact peak and a 12.3% higher loading rate than the conventional shoe; at 10 km/h the impact peak was 6.4% higher. There were no differences in step length, contact time, or cadence between shoe conditions.

Mechanistically, runners wearing the maximalist shoe showed significantly greater leg stiffness (p = 0.007) and compressed their legs about 3.1-3.2 mm less during stance than in the conventional shoe. Peak vertical force changed with speed: it was ~38 N lower in the maximalist shoe at 10 km/h but ~41 N greater at 14.5 km/h, producing the larger impact metrics at faster speed. The results demonstrate that increased midsole cushioning provokes a stiffer leg response that amplifies, rather than attenuates, impact loading - offering a biomechanical explanation for why more cushioning has not reduced running injuries.