Gymnastik- och idrottshögskolan, GIH

Advanced footwear technology (AFT) has reshaped distance running performance, but concerns remain regarding its potential biomechanical implications discussed in the injury literature. This study investigates whether the improved running economy provided by AFT occurs without systematic increases in biomechanical variables that have been discussed in the literature in relation to running-related injuries. Thirty recreational runners completed treadmill trials in three shoe conditions: Nike Vaporfly 3 (NV3; PEBA foam + carbon-fiber plate), Nike Invincible 3 (NI3; PEBA foam), and Brooks Levitate 5 (BL5; TPU foam). Running in each shoe was conducted at 10.8 and 12.6 km·h^-1. Oxygen uptake, heart rate (HR), and biomechanical variables related to injury risk (vertical average loading rate (VALR), vertical instantaneous loading rate (VILR), braking impulse, contact time, and contralateral pelvic drop) were analyzed using a two-way repeated measures ANOVA. Compared with both NI3 and BL5, NV3 significantly reduced oxygen uptake (mean difference: -1.749 ± 0.259 and -1.914 ± 0.215 mL·kg^-1·min^-1, respectively, p < 0.001) and HR (mean difference: -4.750 ± 0.637 and -5.433 ± 0.720 beats·min^-1, respectively, p < 0.001). The BL5 exhibited substantially higher VALR and VILR than both NV3 and NI3 (all p < 0.001) and NV3 exhibited significantly higher VALR values than NI3 (p = 0.006). Braking impulse was lowest in NI3, and no significant shoe condition effects were observed for contralateral pelvic drop or contact time. AFT shoes combining PEBA foam with a carbon-fiber plate improved running economy without increases in the biomechanical variables examined, which have been discussed in the literature in relation to running-related injuries. AFT shoes can enhance metabolic performance, while PEBA-only shoes may better suit sessions focused on cushioning and impact management.