Background Quantifying the potential benefits of advanced footwear technology(AFT)track shoes(i.e.,“spikes”)in middle-distance events is challenging,because repeated maximal effort trials(as in sprinting)or aerobic ...Background Quantifying the potential benefits of advanced footwear technology(AFT)track shoes(i.e.,“spikes”)in middle-distance events is challenging,because repeated maximal effort trials(as in sprinting)or aerobic running economy trials(as in long-distance running)are not feasible.Methods We introduce a novel approach to assess the benefits of AFT spikes,consisting of a series of 200-m runs at self-perceived middle-distance race pace with 10 min recovery,and conduct 4 experiments to evaluate its validity,sensitivity,reproducibility,and utility.Results In Experiment 1,participants ran 1.2%slower in spikes with 200 g added mass vs.control spikes,which is exactly equal to the known effects of shoe mass on running performance.In Experiment 2,participants ran significantly faster in AFT prototype spikes vs.traditional spikes.In Experiment 3,we compared 2 other AFT prototype spikes against traditional spikes on 3 separate days.Group-level results were consistent across days,but our data indicates that at least 2 separate sessions are needed to evaluate individual responses.In Experiment 4,participants ran significantly faster in 2 AFT spike models vs.traditional spikes(2.1%and 1.6%).Speed was similar between a third AFT spike model and the traditional spikes.These speed results were mirrored by changes in step length as participants took significantly longer steps in the 2 faster AFT spike models(2.3%and 1.9%),while step length was similar between the other spikes.Conclusion Our novel,interval-based approach is a valid and reliable method for quantifying differences between spikes at middle-distance running intensity.展开更多
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partly supported by a research contract from PUMA SE with the University of Massachusetts,Amherst.
文摘Background Quantifying the potential benefits of advanced footwear technology(AFT)track shoes(i.e.,“spikes”)in middle-distance events is challenging,because repeated maximal effort trials(as in sprinting)or aerobic running economy trials(as in long-distance running)are not feasible.Methods We introduce a novel approach to assess the benefits of AFT spikes,consisting of a series of 200-m runs at self-perceived middle-distance race pace with 10 min recovery,and conduct 4 experiments to evaluate its validity,sensitivity,reproducibility,and utility.Results In Experiment 1,participants ran 1.2%slower in spikes with 200 g added mass vs.control spikes,which is exactly equal to the known effects of shoe mass on running performance.In Experiment 2,participants ran significantly faster in AFT prototype spikes vs.traditional spikes.In Experiment 3,we compared 2 other AFT prototype spikes against traditional spikes on 3 separate days.Group-level results were consistent across days,but our data indicates that at least 2 separate sessions are needed to evaluate individual responses.In Experiment 4,participants ran significantly faster in 2 AFT spike models vs.traditional spikes(2.1%and 1.6%).Speed was similar between a third AFT spike model and the traditional spikes.These speed results were mirrored by changes in step length as participants took significantly longer steps in the 2 faster AFT spike models(2.3%and 1.9%),while step length was similar between the other spikes.Conclusion Our novel,interval-based approach is a valid and reliable method for quantifying differences between spikes at middle-distance running intensity.
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.
