The advent of the carbon-plated running shoe, in support of the first, historic sub 2-hour marathon, has
resulted in an arms race across various running shoe companies in hopes of providing a similar
competitive advantage to their athletes and customers. Research has shown these new shoe technologies
can significantly improve running economy. However, of the limited research, most is focused on just one
brand and model of carbon-plated shoe. If athletes are to compete on a level playing field, further
investigation is needed to determine that these new shoe technologies confer a similar competitive
advantage across multiple brands and models. PURPOSE: Case study comparison on the effects of two
carbon-plated running shoes (Hoka CarbonX vs. Nike Zoom Alphafly Next%) and a traditional
running/racing shoe (Hoka Tracer 2) on running economy and running mechanics. METHODS: Data was
collected on one male distance runner (age: 35 years, height: 178 cm, weight: 67.7 kg) on two separate days.
On the first testing day, the Tracer 2 (TR) was compared to the Carbon X (CX). On the second testing day,
the CX was compared to the Alphafly (AF). Following a 10-minute jog, a series of 4 x 6 minute trials (two
trials per shoe, randomized) were completed at 13.84 km/hr (~7:00/mile pace) and at 15.29 km/hr
(~6:20/mile pace) with a 4-minute break between trials. Oxygen consumption (VO2) was recorded
continuously throughout each trial and the final 3 minutes were averaged. Further, the two trials in a
given shoe at a given speed were averaged to make comparisons between shoes. Similarly, heart rate (HR),
ground contact time (GCT), cadence, and vertical oscillation (VO) were measured (Garmin, HRM-Tri).
RESULTS: On day 1, comparisons (mean ± SD, %difference) of the TR to CX at 13.84 km/hr were as
follows: VO2 (ml/kg/min; TR: 46.9 ± 0.2, CX: 46.8 ± 0.6, -0.3%), HR (bpm; TR: 170 ± 0, CX: 169 ± 3, -0.7%),
GCT (ms; TR: 201 ± 0.1, CX: 203 ± 1.8, 0.7%), Cadence (steps/minute; TR: 171 ± 0.8, CX: 172 ± 0.1, 0.3%), VO
(cm; TR: 11.3 ± 0.2, CX: 11.2 ± 0.1, -1%) and at 15.29 km/hr: VO2 (TR: 51.3 ± 0.1, CX: 51.2 ± 0.1, -0.1%), HR
(TR: 179 ± 0.9, CX: 179 ± 1.9, 0%), GCT (TR: 195 ± 1.1, CX: 193 ± 0.5, -1.2%), Cadence (TR: 173 ± 0.4, CX: 172
± 0.7, -0.3%), VO (TR: 10.8 ± 0, CX: 11 ± 0, 2%). On day 2, comparisons of the CX to AF at 13.84 km/hr were
as follows: VO2 (CX: 45.7 ± 0, AF: 43.9 ± 0.2, -3.8%), HR (CX: 170 ± 0.6, AF: 168 ± 1.9, -1.3%), GCT (CX: 202 ±
0.2, AF: 205 ± 1, 1.3%), Cadence (CX: 173 ± 0.6, AF: 169 ± 0.1, -2.3%), VO (CX: 10.4 ± 0.1, AF: 11.0 ± 0.1,
5.7%) and at 15.29 km/hr: VO2 (CX: 50.8 ± 0.4, AF: 48.7 ± 0.1, -4.2%), HR (CX: 179 ± 0.2, AF: 177 ± 1.8, -
0.9%), GCT (CX: 193 ± 0.2, AF: 197 ± 0.4, 1.7%), Cadence (CX: 175 ± 0.7, AF: 171 ± 1.8, -2.3%), VO (CX: 10.4
± 0.1, AF: 11.1 ± 0.4, 6%). CONCLUSION: Compared to the TR, the CX did not result in meaningful
differences in economy or mechanics in this case study. However, the AF improved economy by ~4%
compared to the CX, while increasing vertical oscillation (6%) and decreasing cadence (2.3%). While
statistical inferences cannot be made from this case study analysis, these findings do raise concerns on the
relative advantages offered by new shoe technologies across different brands and models of shoes.
Click to expand...