Alemu et al. 2025, uphill training and middle-distance performance

Randomised controlled trial in 40 moderately trained middle-distance runners aged 16–20 (Scientific Reports). Eight weeks of twice-weekly treadmill uphill training at gradients of 2.5%, 5.1% or 7.6% versus control. The steeper 7.6% gradient significantly improved maximal velocity (+0.93 m/s) and 800 m time trial against control, outperforming shallower gradients. Direct performance evidence for uphill training, though sample is modest and athletes are young.