Ankle anatomy and the power of dorsiflexion

How is that for a riveting title? (Because everyone enjoys reading about the ankle joint in their spare time). The ankle joint is one of those joints everyone can point to, but not everyone knows how to use. It connects the foot the lower leg, provides proprioceptive feedback to the sensory nervous system (Hertel, 2002), and is necessary for efficient gait mechanics. What happens when the ankle joint functions more as a cast, uniting the lower leg to the foot? How does that affect movement quality and why should people coaching movement care?

The ankle joint is actually made up of three different joint articulations (Hertel, 2002). These three joints work together to allow coordinated movement of the rear foot (see picture). The ankle enables the rearfoot to move in a variety of ways.  During gait, this coordinated movement allows force to be absorbed and the body to be propelled forward. During more “functional” movements, like the squat or lunge, having adequate ankle mobility and stability enables coordinated movement to occur all of the way up to the hip joint. Our ability to move easily is determined by many factors, including whether the joints can allow adequate movement to occur. This provides sensory input the brain about where our body is located in space and distributes load in a more equal way.

The talocrural joint (or tibiotalar joint, depending on what you’re reading), acts like a hinge when isolated, allowing the foot to point (plantarflex) or extend (dorsiflex). During weight bearing, the talocrural joint transmits torque from the lower leg to the foot. It is made up of the dome of the talus, the medial malleolus, the tibial plafond, and the lateral malleolus. One of the (often ignored) functions of this joint is when the foot is planted during walking, lunging, or squatting, mobility at this joint allows the tibia to move forward. This is called closed-chain dorsiflexion, a concept we will return to later (I know you are on the edge of your seat in anticipation). 

The subtalar joint also converts torque from the lower leg to the foot, but instead of allowing motion (primarily) to occur in the sagittal plane, movement occurs in the frontal plane through foot pronation and supination (pronation is when the arch comes towards the floor, supination is when the arch pulls away from the floor. Both are necessary during the gait cycle). The subtalar joint is the articulation between the talus and the calcaneous.

The distal tibiofibular joint is the articulation between the tibia and the fibula near the ankle. While there isn’t much movement between the tibia and the fibula, accessory gliding between these two bones is necessary for normal ankle mechanics. The joint is stabilized by a thick sheath of connective tissue called the interosseous membrane.

The large amount of mechanoreceptors in the ankle collateral joint ligaments provide feedback regarding joint speed (Wu et.al, 2015). In addition, the ankle provides valuable proprioceptive feedback to the brain regarding posture and balance (Goble, et.al, 2011). If the ankle lacks mobility, this will affect feedback regarding joint speed and posture. The impact on sensory input as well as the impact on force transmission mentioned above makes a strong argument for active ankle joint mobility.*

There are a number of ways to work on ankle joint mobility. I made the case above for the fact that the ankle joint moves in a variety of different ways. Below are two examples of joint mobility exercises I frequently use with clients to begin improving awareness of the ankle joint. They are both circular in nature. One is open chain (done with the foot moving around the ankle and the foot not in contact with anything). The second is closed chain (the body moves around the ankle). Improving awareness of how a joint moves is an effective way to reduce fear around joint movement and get the client comfortable with how the area works. 

After helping the client isolate the ankle joint, the next step is building strength in a dynamic way. While eccentric calf raises are great at teaching the foot how to control dorsiflexion against gravity, the ability to actively dorsiflex in a closed-chain condition may be more important for dispersing load up the lower extremity and reducing load at the knee, specifically the ACL (Dill, et.al, 2014). Load at the knee also depends on what happens at the hip joint, but since this is a blog about the ankle, we will focus on the hip a different day. (And practicing loading joints in a variety of ways makes the connective tissue surrounding the joint stronger. But first you have to be able to isolate the joint). In addition, in a small study that looked at 20 women over the age of 25, the only lower leg strength measure that corresponded with increased risk of falling was ankle dorsiflexion (Skeleton, et.al, 2002). If you work with older adults, there is no doubt you have at some point witnessed the foot shuffle. Often, improving mobility and strength at the ankle will have a positive effect on how a person picks up his feet (total body strength also does wonders. But again, trying to stay focused).

https://www.youtube.com/watch?v=TelMWTiXTJ8

https://www.youtube.com/watch?v=K-H7krq6WAo

Active dorsiflexion can be practiced in a number of ways.** If you teach down dog in any capacity, and you consistently encourage reaching the heels to the floor, more than likely, the students whose heels aren’t on the floor don’t notice much change, class after class. Similarly, if you work in a personal training setting or are someone that struggles with “tight” calves, you probably notice stretching doesn’t get you very far. This is where concepts from FRC come in handy. Lifting the front of the foot off of the ground in a position such as down dog will begin to build strength and control at the ankle joint (or pretending to lift, if there is no way the lift will happen). You can play with this in a variety of positions, both with straight knees and with bent knees (that will affect what you experience at the ankle. As I have discussed in previous blogs, variety is good).

https://www.youtube.com/watch?v=lqOB3Gg6YI0

When programming ankle mobility work into a client’s program, I like to spend about five minutes total going through awareness, and then working on dynamic strength. Once the ankle has been used in a variety of ways, I will usually integrate the concepts into something the client traditionally struggles with, such as a bodyweight squat or a lunge position, so the client can experience the difference in awareness and ease of movement. 

Ankles matter. So do hips, knees, ribs… No one body part is more important than the other. Taking the time to explore strength in different areas and perform more nuanced work can improve the way the parts support the whole.

Yours in health and wellness,
Jenn

*I wrote this from the perspective of having limited range of motion at the ankle joint. If you are hypermobile at the ankle joint, some of these concepts might not apply. Instead of focusing on mobility, you will want to focus on improving control and strength.
**Remember, if you experience pain when doing in the front of the ankle when doing any of this work, be sure to get checked out by a medical professional. 

Resources:
Hertel, J, (2002). Functional anatomy, pathomechanics, and pathophysiology of lateral ankle instability. Journal of Athletic Training, 37(4), pp. 364-375.

Wu, X., Song, W., Zheng, C., Zhou S., & Bai, S., (2015). Morphological study of mechanoreceptors in collateral ligaments of the ankle joint. Journals of Orthopedic Surgery Research, 10(92).
Goble, D.J., Coxon, J.P., Van Impe, A., Geurts, M., Doummas, M., Wenderoth, N., & Swinnen, S.P., (2011). Brain activity during ankle proprioceptive stimulation predicts balance performance in young and older adults. The Journal of Neuroscience, 31(45), pp. 16344-16352.

Dill, K.E., Begalle, R.L., Frank, B.S., Zinder, S.M., & Padua, D.A., (2014). Altered knee and ankle kinematics during squatting in those with limited weight-bearing-lunge ankle-dorsiflexion range. Journal of Athletic Training, 49(6), 723-732.