Hill Running: The Ankles Have to Get it Somewhere.
Get what ? They have to get the dorsiflexion or ankle rocker somewhere. One has to get the ankle dorsiflexion range somewhere and if it is not at the ankle mortise one can snag it from somewhere else, but at a cost.
Remember, we need a requisite 10 degrees (preferably 15 degrees) of ankle dorsiflexion to walk and run normally (the starting reference point is 90 degrees perpendicular to the ground). You should have 30-35 degrees! (You will tap into most of this with up hill running). This motion needs to be matched with available hip extension. When one (i.e. hip extension or ankle dorsiflexion) is limited, the other is usually impaired as well.
When someone has a limitation in ankle rocker it can be found elsewhere possibly, and often, at a cost. Increased midfoot pronation is a classic strategy. If one collapses the arch enough the talus will drop forward and inwards (we know that the normal talar movement in pronation is Plantarflexion, adduction and medial rotation). These 3 combined motions will also tip the tibia forward and help to achieve the sufficient forward motion of the joint complex to allow sagittal progression of the body. The problem with this is that if the amount of pronation is too much the foot will splay compromising the foot tripod, excessive pronation will occur putting the tibialis posterior and plantar fascia at risk as well as other structures, and when this occurs the tibia will excessively internally spin dragging the knee into a valgus/medial moment thus possibly creating patellar tracking issues and significant strain on the MCL and menisci as well as other components. Increased foot progression angle, with increased forefoot pronation is another classic strategy. This option maintains the normal sagittal knee progression path, but at a cost. Many folks will attempt to mitigate biomechanical limitations when running hills by either knowingly or unknowingly turning the feet outwards. This will also allow for the increased foot pronation, internal tibial spin and valgus knee collapse BUT the turn out (increased foot progression angle) will still keep the forward/sagittal knee progression angle. So, they are still creating all of the other pathologic compensations but fooling the knee into a forward/sagittal progression. Mind you, this is a mere smoke screen because the same detrimental foot, ankle and knee mechanics are still occuring. The knee may be hinging forward but it is still doing so through a valgus hinge.
In these photos we see a huge steep hill incline represented by the Merrell loop. The inclination at foot strike is quite significant and so this represents in many ways a steep hill climb. There are 2 photos here so be sure to click to see both. The first one (white shirt) shows just how much ankle dorsiflexion is necessary to run on this “hill” (we wonder if Merrell knows they are asking their runners to hill run at the ankle/foot level?). It is hard to tell in the second picture but one might hallucinate that the stance foot is heavily pronating and collapsing inward. None the less, she is still cranking out a huge ankle dorsiflexion/ankle rocker range of motion. IF you do not have enough ankle dorsiflexion/rocker, as we discussed today, you may have to ask for it somewhere else and that could be a problem in time.
Hills and happy knees, Hills and unhappy feet, knees and hips. It is up to you, if you are paying attention. So many people do not.
Shawn and Ivo, The Gait Guys. Life is an uphill struggle, manage it well and you will have happy biomechanics your golden years.