Downhill running: how to train your legs for descents

Ask runners what hurt most after a mountain ultra and few will say the climbs. It's the descents: quads that won't hold you on the last downhill, stairs that feel impossible for three days afterwards. Descending is a skill and a kind of strength that flat running and even climbing don't train. The good news is that legs adapt to it quickly, if you train it on purpose.

Why descents hurt

Running downhill, every step is a small landing. Your quadriceps work to slow you down while they're being stretched: that's eccentric muscle work. It costs less energy than climbing, which is why descending feels easy at the time, but it causes far more small damage inside the muscle fibres.

The result shows up a day or two later as delayed-onset muscle soreness, and in a race as quads that stop absorbing the impact. Heart rate and training load scores barely notice it, so a hilly long run can look easy in your numbers and still leave your legs wrecked.

The repeated-bout effect

Here's what makes downhill training so effective: after a first bout of eccentric exercise, the same exercise causes much less damage and soreness the next time, even weeks later. Studies of downhill running found that a single session protected the legs from much of the soreness and damage of a second one done several weeks afterwards.

The protection fades over weeks to months if you stop, and it's specific: it comes from loading the same muscles in the same way. That shapes the training: start with a small dose, repeat it regularly, and keep it going all season rather than cramming descents in just before the race.

Building descents into a season

Base: the first doses

Start with what feels too little: 5 to 10 minutes of moderate descending at an easy effort, once a week, for example the way down from a hill at the end of an easy run. Expect some soreness after the first one or two; it fades quickly. Add a few minutes every week or two, and pick slightly steeper or rougher paths as it gets easier.

Build: race-like descents

Now the descents should look like the race's. Two ways to do it:

• Long runs with long descents. Choose routes where the downhill is as long and steep as the race's, and run it at race effort, late in the run when your legs are already tired.
• Downhill repeats. Climb at an easy effort, run down at a steady, controlled pace, repeat 4 to 8 times. Climbing back up is the recovery. Keep these to one session a week.

Look at the race's profile: the longest descent and the total descent tell you what to prepare for. A race with 5,000 metres of descent needs weeks with 1,500 to 2,500 metres of descending in the build phase.

Peak and taper

Keep descending in the peak weeks, a little less than in Build. In the last 10 days, keep only short, easy descents: the protection lasts, and fresh legs matter more now.

A sample downhill session (build phase)

About 75 minutes on a hill with a runnable descent of 5 to 8 minutes:

1. 15 minutes easy on the flat or rolling ground.
2. Hike or run up easily, about 6 to 8 minutes.
3. Run down at a steady, controlled effort: quick steps, relaxed shoulders, as close to race pace on descents as you can hold with good form.
4. Repeat 5 to 6 times. Stop early if your form gets sloppy: tired descending is where ankles turn.
5. 10 minutes easy to finish.

Do it once a week at most, not the day before a long run, and expect your quads to tell you about it the first time.

Shoes and poles

Grip matters more than cushioning on technical descents: a shoe with good lugs and a secure fit around the midfoot lets you trust your steps. More cushioning helps on long, smooth descents and late in a race. If you'll use poles in the race, train with them on descents too: planting them on steep ground takes load off the quads, but it takes practice to do without tripping.

Eccentric strength in the gym

Strength training adds protection with less pounding than running downhill. Slow lowering phases train exactly the braking work descents need:

• Step-downs from a box, 3 to 4 seconds down, 3 sets of 8 per leg.
• Slow split squats or lunges, lowering in 3 seconds.
• Reverse Nordic curls or wall sits for quad endurance.
• Calf raises with a slow lowering, for ankles on rough descents.

Our guide to strength training for trail runners shows how to fit this into two short sessions a week.

Technique: light and quick

• Short, quick steps. More steps with less impact each. Overstriding with a straight leg is the main source of quad damage and of falls.
• Lean with the slope, not back. Leaning back puts the brakes on with every step.
• Eyes three to five metres ahead, planning where your feet go next.
• Arms wide for balance on rough ground.
• On very steep ground, walking down with small steps or using poles saves more than it costs.

Descending on race day

Even with trained legs, the first descents of a long race are where many runners lose the end of it. Running the early downhills fast feels free, because heart rate stays low, but the muscle damage adds up. Hold back on the first half's descents: smooth, relaxed, a little slower than you could. The minutes you give away early are small next to the ones you save in the last hours, when legs that can still descend pass dozens of runners walking down.

Reading your legs

Some soreness after the first downhill sessions is expected. Soreness that lasts more than three or four days, or gets worse each week, means the dose went up too fast: hold it for a week or two. Sharp pain in a knee, a shin or a foot is different from muscle soreness; if it doesn't settle with a few easy days, see a doctor or a physiotherapist.

Read next

• Strength training for trail runners: what, how much and when
• How many hours a week to train for a 50 km, 100 km or 100 mile race

Sources

1. Byrnes WC, Clarkson PM, White JS, Hsieh SS, Frykman PN, Maughan RJ. Delayed onset muscle soreness following repeated bouts of downhill running. Journal of Applied Physiology, 1985; 59(3): 710–715.
2. McHugh MP. Recent advances in the understanding of the repeated bout effect: the protective effect against muscle damage from a single bout of eccentric exercise. Scandinavian Journal of Medicine & Science in Sports, 2003; 13(2): 88–97.