The effect of carbon fiber plated shoes on submaximal running mechanics in non-elite runners

Running shoes constructed with midsole carbon fiber (CF) plates are often worn by elite long-distance runners and may result in mechanical and physiological changes (e.g. increased ground reaction forces, metabolic savings, and speed); however, the effect of these shoes is unknown in a non-elite population. We investigated biomechanical variables in non-elite runners running at submaximal speeds wearing the Nike ZoomX Vaporfly NEXT% 2 shoes (Next%), a shoe with CF plates and specialized energy-returning foam, compared to a shoe without CF plates (Pegasus). 12 male (20.75 +/- 0.62 years) and 18 female (22.94 +/- 5.06 years) runners were recruited. Following a warmup (400 m) in their own shoes at their preferred pace, runners ran 800 m twice, once in each shoe: Pegasus or Next%. Stride frequency during the shoe trials was controlled (via metronome) to preferred stride frequency recorded in the warmup. Wearable running analysis IMUs were worn to collect data. Stride length was significantly greater (p < 0.000) in Next% (2.97 +/- 0.49 m) than in Pegasus (2.85 +/- 0.46 m). Horizontal GRF was significantly higher (p = 0.009) in Next% (9.35 +/- 1.92 N/kg/s) than in Pegasus (8.72 +/- 1.41 N/kg/s). While wearing the Next% shoe, non-elite runners exhibited a significant increase in stride length and horizontal GRF while maintaining a constant stride frequency which ultimately resulted in an increase in running speed.