Many individuals, especially runners, put a lot of thought into our footwear. Runners, will ask us what is the best brand or type of shoe for them? However, as clinicians, we often direct their attention to what goes in the shoe. A shoe is comparable to a vitamin supplement when dieting. The foot itself and the function of the foot is the wholefoods that you consume throughout the day. The point is, you can't take supplements to mask a poor diet and you also can't throw a shoe on a weak foot and expect performance to increase and injuries to completely go away.
With that being said, let us dive into some ways we asses the foot and strengthen the foot to avoid these common injuries and conditions that are common in both the general population and runners.
We will usually start by assessing the big toe and how mobile it is. First toe extension is the ability to bend the first toe backwards. This is very important in walking and especially running.
Adequate first toe extension is important as it allows for proper toe-off and propulsion. This will activate the windlass mechanism. The windlass mechanism occurs as the first toe extends backwards and the plantar fascia tightens which creates a stable arch in the foot.
Fig 1: Example of the windlass mechanism. You can see in the right picture as the big toe extends it will activate the arch of the foot
This stable arch allows for the supination of the foot and rigid support for the push-off. In the absence of this, the foot will pronate or cave in, which will reduce the ability to generate force and can add stress to other structures of the foot.
The inability to extend the first toe is often referred to as “hallux limitus” or in the case of complete lack of motion “hallux rigidus”. This can occur due to stiffness in the muscles or capsule around the foot, or joint changes such as arthritis. Someone with these limitations may develop a bunion or a hallux valgus which is when the toes point inward.
Some risks for developing this limitation may include tight footwear, previous injury, muscle imbalances, or flat feet.
Extension requirements for the big toe vary depending on activity. However, an individual should be able to reach 60 degrees of extension to allow for proper gait when walking and running. For jumping and sprinting activities, the requirements may be as much as 100 degrees.
Test this yourself
What does it test for? Ability to extend the first toe.
Why is it important? Extension of the first toe initiates the “windlass” mechanism. This increases tension on the bottom of the foot, increasing the arch for propulsion. The inability to extend the first toe can lead to overpronation, bunion formation, Achilles injury, metatarsal stress fracture. Approximately 60 degrees or more of extension is needed for normal propulsion
o Inability to extend 40-60 degrees.
Advice: Extension stretches and/or “short foot” exercises.
Common sensations are some discomfort or stretching in the arch of the foot or ball of the foot. If this is the case the plantar fascia, deep muscles of the foot or joint capsule of the foot may be restricting motion. To improve range, we can simply stretch these structures.
Along with stretching it is important that we strengthen the structure that influences this joint. In this case, we can strengthen the deep muscles of the foot which assist in supporting the arch and allowing for efficient toe-off.
Check out the video below to get a brief overview of how to strengthen the deep muscles of the feet and increase the mobility of that big toe.