Foot problems are no different. In fact, there may be no greater challenge to a runner–that is most heavily impacted by running form–than foot problems, namely blisters and toenail pain. (Read this terrific and recent article by Liza Howard on preventing and treating blisters.) These two particular issues are intimately connected to running efficiency. Inefficient foot landing causes excessive and detrimental forces to the feet, and over time, can lead to serious and potentially devastating foot problems that can derail a run. Thankfully, there’s hope, if you can run efficiently, you’ll seldom have foot problems.
The evidence lies with our elite runner. Unlike other common ultrarunning ailments like bonking and nausea, seldom do the sport’s very fastest (and, more specifically, most efficient) runners have any foot problems. They usually wear normal (technical-fabric) running socks, and seldom ever apply tape, powders, or other elements to their feet. How do they do it? Here are some insights into how running forces impact our feet and how to mitigate or reduce foot problems during your long trail race.
The Mechanics of Foot Problems: Shearing and Compression
Blisters and toenail pain are generated by excessive landing forces:
- Shear (or friction) force. This is defined by the movement of one part of a system, along and in parallel to a stable (or oppositional) surface.
- Compressive force. This is a perpendicular force of one object in collision with another (usually stationary) object.
It is these forces that create foot problems. And while there are myriad elements that can sensitize the feet or compound their effects, without these forces, there are no foot problems. As such, mitigating them is the key to avoiding foot problems.
The How and Why of Blisters and Toenail Pain
Blisters are formed from shear forces. The foot (or more accurately, layers of tissue within the foot) slide around within in the shoe, and in interaction with the sock. But where do these forces come from? Two of the primary shear stresses come from overstriding and overpronation. (More on these to come.)
Toenail pain arises from compressive forces. Quite simply, the toes slam into the front of the toebox of the shoe while we run. This compression can be ‘traumatic’–of the foot slamming into a rock or root along the trail–or micro-repetitive, via general inefficiency like overstriding and overpronation.
Two Foot-Killing Stride Habits
Efficient foot strike occurs when the foot lands only a few inches in front of the trunk. This is important to both mitigate excessive landing stress, and to orient the leg beneath the body for pushoff. By definition, overstriding occurs when (any part of) the foot lands significantly in front of the body. In doing so, excessive landing stress must be absorbed by the legs, rather than used for propulsion. As such, overstriding is the number-one factor of nearly every running problem and injury. An overstride landing can create excessive shearing and compression stress, and it is the overwhelming cause of both blister formation and toenail trauma.
Lateral or Narrow Striding
A lateral or narrow foot strike is another potent stressor to the feet. Ideally the feet land directly beneath the body, if not slightly under its respective side of the body. A ‘cross-over’ landing pattern occurs when the foot lands so narrowly that it crosses the midline, and when this occurs, the foot strike is almost always excessively lateral. This lateral landing is a setup for excessive pronation force as the medial part of the shoe must travel farther to get to the ground. Then, inside the shoe, the foot is both compressing and shearing during this pronation crash down.
Reducing Foot Problems: Efficiency First!
Here are some key stride-efficiency concepts–things the pros do extremely well–to avoid foot problems:
This is much easier said than done, but efficient footstrike boils down to two concepts:
- Hip Hinge. Efficient forward engagement is important, but how to sustainably do so is widely debated. In my clinical, coaching, and personal experience, a ‘forward lean’–one where you simply lean forward at the ankle–is not sustainable. Rather, a hip hinge, ‘the universal athletic position,’ both sustainably pitches the trunk forward as well as improves hip loading. A forward trunk makes it easier for the foot to land beneath it.
- Foot Beneath You. While there are many strategies for doing so, a simple awareness of placing the foot beneath the body is a crucial starting point. A more hip-centric up-and-down movement, as well as a pawback pulling motion, are next-level strategies to ensure landing efficiency. (Read on for more on this.)
Land Beneath You on Your Whole Foot
While seemingly common sense, a whole, balanced-foot landing beneath the body can be a big challenge for most runners, especially on varied topography and terrain. To avoid overstriding, landing beneath the body is a crucial strategy to avoid excess foot stress. Additionally, engaging the whole foot–namely the medial arch and not just the lateral margin–is enormously important to avoid the narrow, cross-over or lateral foot striking that cause major hyper-pronation stresses. Feel your whole foot land beneath you!
Sit (or Ski) Downhill
The downhills of a mountain-trail race provide enormous potential compressive and shear forces. For most runners, even the fastest amongst us, the concept of ‘leaning into’ a downhill is terrifyingly suicidal. Thankfully, there’s an easier way to improve landing efficiency. A hip hinge on a downhill is a crucial strategy to pitch the trunk forward, while still feeling safely in control. Unsure what a hip hinge feels like? If you’ve ever downhill skied, then you know the feeling. If not, then the idea of ‘sitting into the hill’ may make more sense. This hip-hinged position not only helps improve foot strike, but it also shifts the landing stress into the hip joint, decreasing landing stress throughout the entire leg and focusing it in the glutes.
Pawback (or ‘Tap Dance’)
This final cue is among the most challenging but potent strategies to avoid foot stress. The Pawback is a pull-through strategy that helps both orient the footstrike underneath the body as well as propel the leg behind. It is a one-two punch of landing efficiency and stride endurance and power. It’s also a key strategy on the downhills. Since there is no propulsive element on steeper downhills, I liken a pawback strategy to a downhill ‘tap dance.’
Solving Problems: The Efficiency Rule and Moving Forward
Even with our best stride efforts, foot problems can happen. When they do, solve them (and be prepared to do so). That said, the emphasis here is that you have more control over foot problems than you may realize. Even if foot blisters and toenail destruction befall you, mitigating further irritation and damage is possible by working these stride strategies.
Nearly as good, these strategies fall into ‘The Efficiency Rule:’ “Any strategy that sustainably relieves [or prevents] pain will make you faster!”
Accentuating forward engagement and foot landing will not only decrease potential foot problems, but also decrease all leg stress and hopefully get you to the finish line faster and feeling better! Take control. Fix your feet before they’re broken!
Call for Comments (from Meghan)
- Have you thought about the specific circumstances of when and how you get blisters or black toenails on a long run?
- Do you feel them on the downhills? On flatter terrain? Something different?