Purpose This study aimed to determine the independent effect of the curved carbon-fiber plate in the Nike Vaporfly 4%shoe on running economy and running biomechanics.Methods Fifteen healthy male runners completed a me...Purpose This study aimed to determine the independent effect of the curved carbon-fiber plate in the Nike Vaporfly 4%shoe on running economy and running biomechanics.Methods Fifteen healthy male runners completed a metabolic protocol and a biomechanics protocol.In both protocols participants wore 2 different shoes,an intact Nike Vaporfly 4%(VF_(intact))and a cut Nike Vaporfly 4%(VF_(cut)).The VF_(cut) had 6 medio-lateral cuts through the carbon-fiber plate in the forefoot to reduce the effectiveness of the plate.In the metabolic protocol,participants ran at 14 km/h for 5 min,twice with each shoe,on a force-measuring treadmill while we measured metabolic rate.In the biomechanics protocol,participants ran across a runway with embedded force plates at 14 km/h.We calculated running economy,kinetics,and lower limb joint mechanics.Results Running economy did not significantly differ between shoe conditions(on average,0.55%±1.77%(mean±SD))worse in the VF_(cut) compared to the VF_(intact);95%confidence interval(-1.44%to 0.40%).Biomechanical differences were only found in the metatarsophalangeal(MTP)joint with increased MTP dorsiflexion angle,angular velocity,and negative power in the VF_(cut).Contact time was 1%longer in the VF_(intact).Conclusion Cutting the carbon-fiber plate and reducing the longitudinal bending stiffness did not have a significant effect on the energy savings in the Nike Vaporfly 4%.This suggests that the plate's stiffening effect on the MTP joint plays a limited role in the reported energy savings,and instead savings are likely from a combination and interaction of the foam,geometry,and plate.展开更多
基金We thank the subjects for participating,Sam Zeff for helping with mechanical testing,Sam Carey for helping cut the shoes,and Justin Ortega,Dale Haavind-Berman,Emily Laughlin,Annie Lye,and Adam Lee for help with data collection.
文摘Purpose This study aimed to determine the independent effect of the curved carbon-fiber plate in the Nike Vaporfly 4%shoe on running economy and running biomechanics.Methods Fifteen healthy male runners completed a metabolic protocol and a biomechanics protocol.In both protocols participants wore 2 different shoes,an intact Nike Vaporfly 4%(VF_(intact))and a cut Nike Vaporfly 4%(VF_(cut)).The VF_(cut) had 6 medio-lateral cuts through the carbon-fiber plate in the forefoot to reduce the effectiveness of the plate.In the metabolic protocol,participants ran at 14 km/h for 5 min,twice with each shoe,on a force-measuring treadmill while we measured metabolic rate.In the biomechanics protocol,participants ran across a runway with embedded force plates at 14 km/h.We calculated running economy,kinetics,and lower limb joint mechanics.Results Running economy did not significantly differ between shoe conditions(on average,0.55%±1.77%(mean±SD))worse in the VF_(cut) compared to the VF_(intact);95%confidence interval(-1.44%to 0.40%).Biomechanical differences were only found in the metatarsophalangeal(MTP)joint with increased MTP dorsiflexion angle,angular velocity,and negative power in the VF_(cut).Contact time was 1%longer in the VF_(intact).Conclusion Cutting the carbon-fiber plate and reducing the longitudinal bending stiffness did not have a significant effect on the energy savings in the Nike Vaporfly 4%.This suggests that the plate's stiffening effect on the MTP joint plays a limited role in the reported energy savings,and instead savings are likely from a combination and interaction of the foam,geometry,and plate.
