Running Economy Benefits of Advanced Footwear Technologies Remain over a Prolonged Run in Highly Trained Distance Runners – A Randomized Crossover Trial

ABSTRACT Purpose Running economy (RE) improvements in advanced footwear technologies (AFTs) have been investigated during short running bouts, while performance enhancing effects may be greater over longer distances. Therefore, the aim was to compare RE and biomechanics during a 90-min run between AFTs and traditional shoes in highly trained distance runners. Methods Nine highly trained distance runners (5 females) visited our laboratory on two separate sessions within 14 days. In each session, they performed a submaximal threshold assessment treadmill test, followed by a 90-min treadmill run. We used linear mixed effects models (with random intercepts for participants) to examine the effects of time, shoe condition, and their interaction on energetic cost of transport (ECOT) and biomechanical measures. Results Participants (age: 32.4 ± 8.4y, body mass index: 20.8 ± 1.2 kg/m 2 ) had a mean maximal World Athletics score of 930 ± 84points, corresponding to 10 km times (min:s) of 30:17 and 36:09 for males and females. ECOT was different between AFT and Non-AFT (β = 0.57 (0.41 to 0.72), p = 0.009) throughout 15 to 90 min. On average, ECOT was 3.18% (95% CI: 2.14 to 4.22) lower in the AFTs compared to the non-AFT condition. Over time, ECOT (β = 0.30 (0.19 to 0.41), p < 0.001) increased by 5.63% (95% CI: 3.00 to 8.27) across both shoe conditions, but was not shoe-dependent (ECOT: p = 0.553). With AFTs, step rate was lower (β = 0.13 (0.04 to 0.21), p = 0.030), flight time longer (β = -0.08 (-0.14 to -0.03), p < 0.001), and contact time (β = 0.05 (-0.00 to 0.11), p = 0.001) shorter than with non-AFTs, but differences disappeared over time. Conclusions There were no differences between shoe conditions in deterioration of RE during the 90-min run, but AFTs maintained their beneficial properties in RE over time and therefore are probably a good choice for long distances.