A Ground-Up Approach to Lower Extremity Functional Stability – Lilian Chung

In this blog post, we have had the opportunity for our very own Physiotherapist, Lilian Chung to present to us exercise prescriptions to improve lower extremity functional stability!

Instability in the lower extremity is most visibly seen through the knee presented by internal rotation of the tibia and valgus knee. The knee is limited in degrees of motion, so we see that functionally its stability is mostly maintained through the foot (talus & arch) and hip (glute) control. Common knee issues are driven from the foot and/or hip.

Taking on a ground-up approach, an important area to consider first and look at is the foot. The foot can influence and affect an individual at any time when in weight-bearing positions such as standing, walking, running, and sports.

Two types of extreme foot morphologies to consider are a high arched foot (pes cavus) and a flat arch foot (pes planus). Proper stability in the foot is attained through maintaining what is known as a ‘tripod’ in the foot, where the 1st metatarsal, 5th metatarsal, and heel remain in contact with the floor and allow for weight/ground forces to be evenly distributed. In contrast, patients who may have either of the two mentioned foot morphologies will have an altered foot tripod, where it is more difficult to maintain the tripod and stability and causing the weight to be unevenly distributed.

It is important to consider the talus as well in that limitations in mobility and/or stability can be contributors to these foot morphologies and kinetic chain dysfunctions that occur. Limited mobility is presented through a stiff talus which opposes foot stability by limiting ankle dorsiflexion and affecting movements and activities that require this mobility (ex. Squats, sprinting, etc). Compensations for this then occur through worsening overpronation of the foot. Limited stability through the foot can be observed through internal rotation of the talus and a resulting medial arch collapse. As depicted this in turn can affect our tripod foot and the rest of the kinetic chain.

How can we improve this?

Cueing and facilitation of the foot can include:

• Improving foot intrinsics (through strengthening the foot to improve the tripod foot, typically when overpronated)
• Facilitating mobility in the talus (external rotation of the talus) and improving dorsiflexion at the ankle with exercises

A key takeaway is to always remember to assess and check the feet! That is it for this post, thank you Lillian for her amazing presentation!