Effects of selected features of advanced footwear technology on lower limb joint work

The objective of this study was to isolate the effects of two key components of Advanced Footwear Technology, the curved carbon fibre plate and the midsole material, on lower-limb joint work. Sixteen male recreational runners ran overground at a speed of 3.9 (±5%) metres per second in three shoe conditions: a standard Nike Vaporfly 4% (Original VP4), a modified version without the curved carbon fibre plate (No Plate) and a version with the PEBA midsole material replaced with EVA foam (EVA). Motion capture and force platform data were recorded to determine positive and negative metatarsophalangeal, ankle, knee, and hip joint work, and positive and negative foot + footwear work across the different conditions. Removing the carbon fibre plate significantly increased negative work at the metatarsophalangeal joint and positive work at the ankle. Replacing PEBA with EVA significantly reduced positive foot + footwear work. The findings of this study highlighted a group effect of the curved carbon fibre plate, which redistributed positive lower-limb joint work from the ankle to the metatarsophalangeal joint. Conversely, the results highlighted subject-specific differences in response to the midsole material, emphasising the importance of considering individual variability in footwear design elements to optimise athletic performance.