The art of descent
For obvious reasons, runners tackling a hilly course tend to fret most about the uphills. But you spend nearly as much time descending as you do ascending (unless you’re finishing on a mountaintop and t aking a helicopter down), so it’s also important to make sure you’re efficient on the way down – otherwise, you’ll lose time to competitors, and pay the price later in the race (or the next day) with sore, deadened legs. That’s because downhill running causes your leg muscles to contract “eccentrically” since you’re braking with each stride, which produces microscopic damage to your muscle fibres.
In a recent review in the European Journal of Applied Physiology, University of Calgary researcher Guillaume Millet – an accomplished ultra-trail runner himself – and his colleagues outlined several researchbacked strategies to minimize muscle damage while running downhill. One option is to increase your cadence, so you’re taking shorter, quicker strides, which reduces the impact of each stride. Another is to vary your foot strike, so that you’re landing on different parts of your sole rather than always the heels or always the toes. To some extent, that may happen naturally on uneven trails; but by making a deliberate effort to mix up how you land, you’ll distribute the load to different muscles in your legs.
Most importantly, Millet and his colleagues suggest that the best way to prepare for running downhill is to, well, run downhill. That’s because of a phenomenon called the “repeated bout effect”: doing any exercise that leaves you sore afterwards will make you less sore the next time you repeat a similar workout. That’s in part because the initial exercise weeds out the weakest muscle fibres and stimulates the growth of stronger ones, and also because of changes in how your whole body responds to damage (exercise in one leg can even make the other leg less susceptible to future damage). There’s no simple recipe for how much downhill training you need, but the best plan is to train on downhills that mimic anything you’ll encounter in a race.