Can Level Ground Biomechanics Predict Uphill and Downhill Running Economy?

Marathon terrain significantly impacts athlete performance. This study examined whether level running biomechanics can predict uphill and downhill running economy using a new metric, running grade aptitude (RGA). Forty distance runners (32 males and 8 females) ran on a split-belt treadmill at +4% and -4% gradients, simulating Boston Marathon hills.