If you’ve ever woken up with burning quads the day after a hilly race, you can probably blame all the downhill pounding. Although running uphill may feel more difficult from a cardio perspective, going downhill well is challenging—and a lot harder on your body.
Here’s why: Muscles contract in two ways—concentrically (muscle shortens: think picking something up) and eccentrically (muscle lengthens while contracting: think putting that something back down). “Eccentric contractions are much more costly from an energy and wear and tear perspective,” says Dr. Ivo Waerlop, D.C. “Running downhill requires lots of eccentric contraction, especially in the quadriceps and lower leg muscles.” Mastering the downhill with proper form will put less stress on your legs and can help you make up time in your next race.
Lean forward from the hips, not the shoulders. Gravity naturally pulls you downhill. Avoid the urge to lean back and focus on keeping your body perpendicular to the ground. “As you increase speed, move your center of gravity forward with you; not enough and your feet are sliding out from under you, too much and you’re on your face,” Waerlop says.
Use your arms for balance. When running downhill, we don’t need the forward-back arm movement for power like we do on flats and uphills. Although it may look ridiculous in race photos, Xterra world champion Lesley Paterson recommends flailing your arms out to the side for balance. “It can help give your body the control it might need if speed takes over or a sudden change in direction is needed,” she says.
Engage your core. Think of your abs, glutes and back as your stable base that your limbs work around.
“Circle” your stride. Because you don’t need as much power from the knee drive (thanks, gravity!), keep the feet under the body and don’t overstride. “I often do an almost circular motion—especially if on steep terrain—rather than driving the knee straight through in front of the body,” Paterson says. “It allows more extension out the back and a chance to relax some of the muscles in the follow-through.”
Read more at: https://www.triathlete.com/training/the-secrets-to-running-downhill-fast/