“Fast and flat course” is a phrase that is utilized to draw some runners into signing up for particular marathons. Hills are stigmatized even in a runner’s masochistic existence in which pushing through pain is the norm. One of the most famous hills is “Heartbreak Hill” beginning around mile 20 of the Boston Marathon that rises 91 feet at a 3.3 % grade. Having run it, I know first hand that it’s a taxing little climb, especially at that time of the race. However, it seems to always be the hill climbing in a race that gets noted more so than any hill descent. The Boston Marathon has a downhill trajectory from the start to about mile 8-9 when the course flattens out a bit. Research supports that this part of the course may actually be more taxing on the body than the climb later. In fact, mastering the downhill run may separate the men from the boys and the women from the girls in terms of performance, especially in trail and mountain running where hills are the norm.
Downhill “pounding” = increased impact force= increased injury risk
When running downhill, the force of gravity is with you. Anyone who runs knows that it feels like your feet are pounding the pavement more when you run downhill than when you are running on flat surfaces or going uphill. This is of concern from an injury prevention standpoint because as the magnitude of the “pounding” or impact forces go up, so does your risk of injury. As the steepness or the grade of the downhill increases, you may have felt as though the pounding increases as well as your muscle soreness in the days following. What you are feeling is backed by research. In a recent study, the impact that women experienced when running at 4 meters per second (8.8 mph, ~6:30 per mile) on an instrumented treadmill at grades of -5, -10, -15 and -20%; researchers found that the impact forces were significantly increased compared to running on level surfaces (Wells et al. 2020). These findings corroborate data generated by Gottshall and Kram (2005) that indicate running down a -2.5% grade increased impact force by 54%. Björklund et al. (2019) specifically studied impact forces that trail runners experience when running downhill, uphill and on level surfaces and found that impact forces were greatest on the downhill segments. The stress of downhill running is evident in the days following your run too. Chen et al (2007) found that running for 30 minutes down a -15% grade decreases running economy 4-7% for several days. Running economy is a measure of how efficient you are or how much energy your body demands to run at a particular speed and corresponds to the amount of oxygen you need to consume in a given unit of time. Chen et al. (2007) found that following a downhill run, runners experienced increased oxygen consumption, decreased maximum strength of muscles around the knee (extensors, specifically), decreased range of motion in the knee and ankle, increased muscle damage, increased rating of perceived exertion (how hard it feels to run), and increased lactic acid levels in the blood. In short, downhill running substantially stresses your body.
Why you should master downhill running to improve your performance
Perhaps you didn’t need the data summary above to prove it to you, but downhill running, without a doubt, is more stressful on your body, than level surface or uphill running. This is exactly why you need to master it. If you are better at running downhill, you will not only reduce the negative physiological effects on your body, but you may also have a significant advantage over your competitors in your next race.
Björklund et al. (2019) identified that speed varied the most among runners during the downhill portions of a trail run, and the more technical the section of the course, the more variable the speeds became. So if you are looking for a window of opportunity to take down your competition on your next trail race, you will probably want to consider working on your downhill running, particularly over technical terrain. Furthermore, Kerherve et al. (2016) found that runners tend to continue losing speed over time when downhill running, whereas speed tends to reduce and then plateau on the flats or uphill segments. Learning how to maintain speed on the downs is key to increasing your competitive edge.
Tips for mastering the downhill run
So if downhill running is stressful on the body, how do we train for it without destroying ourselves? Small doses that allow you to practice mechanics that will reduce impact and prevent injury.
One of the main reasons that people experience greater impact forces when running down hill is that they tend to lean back and run with their feet out in front of them. This is like driving your car downhill with your foot on the brake. This will wear out the brakes on your car quite quickly; in running, it wears out your body and puts you at increased injury risk. At the same time, people tend to run with lower step rate or cadence when running down hill. This means that the foot is spending greater time in contact with the ground, which translates to greater stress on the legs and rest of the body.
Given this, you need to do the opposite of what you likely tend to do. You need to keep your steps short, quick and light with your body over your feet. This can be very uncomfortable for some, because adding a forward lean accentuates gravity’s force to carry you down the hill even faster. You may even feel like you are about to fall. But becoming comfortable with this level of discomfort will not only translate to speed on the downhills, there will be less impact on your body.
As with any new skill, it is better to train it in small doses ….CORRECTLY. And doing downhill running correctly will likely be very uncomfortable at first. But in time, correct practice will make this skill automatic and you’ll be whipping down the hills (and maybe even having fun while doing it) without thinking much about it.
Here is an example of how you can begin to train down hill running after warming up:
- Find a hill that has a grade that is challenging but not utterly daunting for you (only you can define what this is).
- Start at the top of the hill and run down for 10 seconds with good form (high cadence, body over feet).
- Walk back to the top for recovery.
- Run downhill for 20 seconds with correct form and walk back to the top for recovery.
- Continue these repeats, increasing the duration of the downhill run (i.e., 30, 40, 50 and 60 seconds).
- cool down
As this becomes more comfortable, you can work into using hills that you would like to conquer or maybe those that are part of or mimic your upcoming race. Strategically place this in your training schedule so that your intense workouts come earlier in the week before your downhill training session. Remember what the data show— your running economy will be decreased in the days following your downhill workout. When you start training downhill running, shoot for doing this only once per week.
*Increase your cadence (step rate).
*Run quietly, softly.
*Lean forward, from the ankles to keep your body over your feet.
*Practice correct downhill running form in small doses (see example workout above).
*If you feel like you are going to fall forward while running downhill, you are probably doing it right!
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Björklund, G, Swarén, M, Born, DP, Stöggl, TL. 2019. Biomechanical adaptations and performance indicators in short trail running. Frontiers in Physiology. 10: p 506.
Chen, TC, Nosaka, K, Tu, JH. 2007. Changes in running economy following downhill running. Journal of Sports Sciences. 25(1): 55-63.
Gottshall, JS, Kram R. 2005. Ground forces during downhill and uphill running. J of Biomechanics. 30(3): 445-452.
Wells, MD, Dickin, DC, Popp J, Wang H. 2020. Effect of downhill running grade on lower extremity loading in female distance runners. Sports Biomech. 19(3): 333-341.