You want stronger feet you say? The obvious answer to anyone Googling their way to stronger feet is to master the use of clawing and/or spreading their toes. You’ll be instructed to tug on a towel (towel crunch) or simply pick up objects with their feet.
As I usually tout in my articles, our strength, flexibility, and drills should lay on the foundation of function, meaning they should look and feel like running. Without going on a 500 word rant about the towel crunch and its inability to look and feel like running, I thought I would talk about muscle function, the foot, and a more effective way to think about foot strength.
Lengthening vs. Shortening Contractions
Our muscles can contract to either shorten or lengthen. Eccentric, or lengthening contractions are preformed against resistance. In running, this occurs from initial contact to mid stance (the first half of the gait cycle). Approaching midstance the arch lengthens as it absorbs the shock of landing. In reality, the arch lengthens, the tibia spins, the knee bends, and hip rotates. Remember, your leg is a chain of movement, not simply an isolated motion. Controlling the lengthening contractions is uber important. It will allow you to control landing forces and maintain proper alignment for latter stages (ie pushoff). Once through midstance, the muscles transitiong to a shortening contraction. Shortening, or concentric contractions are found primarily in the second half of the gait cycle: midstance to push off. Concentric contractions provide forward movement, shunting force and torque down your leg, through the foot, and into the ground.
Relating Foot Function to Exercise
When training the foot to perform, the pairing of your exercise can make all the difference. Ideally, your goal is train your foot as a link in the kinetic chain that is your leg. Much like your ankle, knee, foot, and trunk, the arch first must control the lengthening contraction. Before we consider any exercise it’s best if we start standing. You’re weight bearing while you’re running, right? Please weight bear during your strength exercise. Second, exercises performed to improve strength should toggle you through both lengthening and shortening contractions. Truthfully, control during our lengthening contractions is the most important. Lack of control on the front half of your gait cycle can wreak havoc on the latter half. Think of it this way: losing the battle against the ground can change your alignment and posture for the second half.
The Towel Crunch
Knowing the basics from above, you can see my beef with the towel crunch. First, the exercise only trains half of the gait cycle, and in my opinion, the less important half. Pulling against the towel will train the foot for shortening contractions only. The concentric or shortening contraction associated with the exercise is often performed non-weight bearing to boot. Continuing on my, what could be a lengthy, rant, the exercise is selective to the foot only. In life and running, our muscles fire together, not as a solo act. A towel crunch fails to link your foot the remainder of your kinetic chain (leg and trunk). Standing balance and reaches can help you link your hip to the foot, improve strength, and maximize balance.
We all love to run and for most of us, strength training is a necessary evil to keep us on track with our true passion: running. Selectively strengthening is a time waster. The towel crunch is a perfect example of applying strength training to the anatomy and not function.