The Secrets to Running Downhill Fast.

Last month we contributed to Jene Shaw’s article in Triathlete Magazine.

Please hit the link here for the entire great article by Jene Shaw. There is lots more here. LINK

http://triathlon.competitor.com/2012/05/training/the-secrets-to-running-downhill-fast_54031

Here were some of our Form tips used in Jene’s article for going fast downhill.

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.

Perfect Foot Position

Think of your foot as a tripod, with the three points being the heads of the big and little toes (at the ball line) and the heel. This tripod needs to be level for the foot to function optimally. If you are too much on your heel, your shins need to slow the descent of the foot, which can lead to shin splints. If you land too much on your forefoot, your calves have to work harder to lower your heel and will exaggerate any forefoot abnormality you have in your gait; this will place additional stress on your knees. —The Gait Guys, Drs. Ivo Waerlop and Shawn Allen

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Here are some other things to remember when running down hill:

Be a drop of water:  The Zen of watching water run downhill can teach us much. Taking the path of least resistance often is the least stressful for our bodies. Though terrain features like rocks, grass and dirt mounds can be useful to control speed, they also cause deceleration of our bodies, which means you need to reaccelerate them (remember Newtons 1st law?). This costs energy and wear and tear on our chassis.  If you need to regulate speed on your descent, use the terrain options as described or angle your approach to one side or another zigzagging the descent.  Taking the descent on an angle enables you to get 2 legs of your foot tripod on the ground almost immediately for added stability and it shifts your center of gravity to a more vertical or stable position, it also puts your body mass closer to the hill. A slip when descending on an angle is a better controlled slip.  As you gain skill, you can point your feet more progressively down hill.

Do your homework:  In the simplest explanation, muscles contract two ways: concentrically and eccentrically. Concentric contractions explain how the muscle shortens as it contracts, like picking up something. Eccentric contractions explain how the muscle lengthens as it contracts, like putting something you picked up back down. Eccentric contractions are much more costly from an energy and wear and tear perspective, as it takes more energy to break bonds between muscle fibers than make them. Running down hill requires lots of eccentric contraction of muscle, especially the quadriceps and muscles on the front of the shins, as there is a shift from glute drive to quadriceps loading. Running hills requires more (or extra) training particularly the eccentric phase for hill descents because of the increased demand. 

The faster you go, the more perpendicular to the ground your body needs to be:   Because of gravity, you are pulled down a hill. Our instinct may tell us to lean away (or backward) as we descend and pick up speed, but that could spell out disaster and perhaps your last run for quite some time. As you increase speed, you need to have your center of gravity move forward with you; not enough and your feet are sliding out from under you, too much and you are on your face. Again, if speed control is getting challenging, like in backwoods steep descents, zigzag your descent. Managing speed but covering more terrain safely is better than being the first down the hill while the last to get out of the first aid tent.

Look down the hill, not at your feet:  Your brain works best pre-planning the next thing it should do, and works better when multitasking. Looking down at you feet actually facilitates your flexor muscles (the muscles which make you bend forward). This does two things: it makes you tend to fall forward and it turns off your extensor muscles (glutes, hams, back muscles) which are (or should be) the muscles in charge to keep you upright.

Engage your core:  Think of your core as your engine and your legs as your transmission. An engine needs to drive the transmission. Your core muscles (abs, glutes) provide a stable platform for the other limb muscles to work upon.  Not having the core engaged makes you more susceptible to injury, just like if your engine mount were broken.

Relax:  Your mind is like a parachute; it works best when open. Stiffening up elicits protective reflexes that could be dangerous while running downhill. Imagine trying to drive your car with the airbag inflated. Let go and follow the flow.

Arm Swing Part 3: Running Downhill on Uneven Terrain.

Today we have a pretty cool video for you. It is perfect stuff for a Sunday blog post. It is called “The Chase”. This team has done something pretty neat and this probably took alot of time to complete. Notice it is the same guy in two different outfits (red chasing black), giving the impression of him chasing himself. It is about pushing yourself to be the best you can.  But there are some clips at 2:17 we want you to pay attention to. Watch his arm swing when he is scrambling down the hill. The arm swing is tight, controlled and helps his core and balance. But there are other costs to doing this, and it gives perfect support to our blog posts from a few weeks ago on arm swing.

If you have not read our posts from December 7-8 (link) it might behoove you to read them now otherwise today’s topic will have limited meaning to you. We are building on this topic of limb swing, and how some of it is passive and some is active from a neurologic control standpoint. 

So, we are back to looking at limb swing again. Particularly arm swing today.  It is important for you to realize, as put forth in:

Huang et al in the Eur Spine Journal, 2011 Mar 20(3) “Gait Adaptations in low back pain patients with lumbar disc herniation: trunk coordination and arm swing.”

that as spine pain presents, the shoulder and pelvic girdle anti-phase begins to move into a more “in-phase” favor.  Meaning that, the differential between the upper torso twist and pelvic twist is reduced (in the drawing above the lines will laterally converge). In our opinion, in threatening motor challenges (such as running downhill at 2:17 in the video above) the body will create a reduction in spine rotation and motion due to the increased activation of the core to maintain balance and stability.  IF this anti-phase is reduced then arm swing will be reduced (as is seen when he is scrambling downhill). The central processing mechanisms do this to reduce spinal twisting, because reduced twist means reduced spinal motor unit compression and this hopefully leads to less pain but also more body control. The consequence to this reduced spinal rotation is reduced limb swing.  Think about this next time you see someone, a runner patient or athlete, with reduced arm swing especially on one side. Furthermore, according to

Collins et al Proc Biol Sci, 2009, Oct 22

“Dynamic arm swinging in human walking.”

normal arm swinging requires minimal shoulder torque, while volitionally holding the arms motionless requires 12 % more metabolic energy, proving that there are both active and passive components to arm swing.  Collins also discovered that among measures of gait mechanics, vertical ground reactive moments are most affected by arm swinging and increased by 63% without it. Wow, 63% !

So, taking this data, one could extrapolate that energy consumption is increased running downhill on uneven terrain. This may be nullified by moving with gravity and the downhill slope.  But on such uneven terrain, if you are smart and not reckless you will be expending energy to slow the downhill chaos so you can remain in control of the descent.  This goes for flat uneven or slippery terrain as well, keep this in mind when you hit some icy patches this season. Thing of The Gait Guys, and note how your body adapts to the surface. The surface has huge impact on how you use your body.

So, it is all about efficiency and protection. Efficiency comes with fluid unrestricted movements and energy conservation but protection has the cost of wasting energy and reduced mobility through a limb(s) and spine.

For you neuro nerds, remember the receptors from the central spine and core fire into the midline vermis of the cerebellum (one of the oldest parts of our brain, called the paleo cerebellum); and these pathways, along with other cerebellar efferents, fire our axial extensor muscles that keep us upright in the gravitational plane and provide balance or homeostasis. And when running downhill you had better be firing your extensors !

Shawn and Ivo …  combining almost 40 years of orthopedics, neurology, biomechanics and gait studies to get to the bottom of things….. to help you become better athletes, better coaches, and better doctors.