top of page
Blog: Blog2

Chronic Ankle Instability (CAI)

Updated: Sep 20, 2021

Have you ever landed awkwardly on your feet while playing sports, or twisted your foot over an uneven surface? What we know as a common ankle sprain may not be as simple as it seems.

Ankle sprains are a common injury to develop in both sporting activities and the general community. Approximately 20% of the population with ankle sprains will eventually develop CAI.

What is CAI?

Generally, ankle sprains occur when the ankle moves into an awkward position which causes the strong ligaments that support the ankle to stretch beyond their limits and tear. For the anatomically savvy people out there, the most common ligaments affected are the anterior talofibular ligament (ATFL) and/or the calcaneofibular ligament (CFL). After an ankle sprain, balance is often affected. It is important to strengthen the muscles around the ankle to retrain the muscles that control balance. Failure to do so may eventually lead to repeated ankle sprains.

As mentioned above, CAI is commonly developed from recurrent ankle sprains. This is mainly due to the sprain itself not being adequately healed or not rehabilitated completely. Each recurrent sprain will cause further weakening/stretching of the ligaments that support the ankle leading to greater instability and balance problems. Balance may not be the only thing affected by a CAI; postural control, proprioception, muscle reaction timing and muscle strength can be negatively impacted as well.

How can I tell whether I have CAI or not?

First, do not panic. Although, recurrent ankle sprain is often closely linked and a primary characteristic of CAI, this does not necessarily mean CAI is present. Other characteristics may be loss of balance, difficulty weight-bearing on the affected ankle, decreased reflex response and control of ankle. To fully confirm a CAI, an in-depth examination by a physiotherapist would be needed to be conducted to confirm if CAI is present or not.

The physiotherapist would usually conduct a detailed subjective interview to gain as much information about the mechanism of injury and how it is affecting daily life or sporting activities. Next a physical exam will be conducted to test balance, muscle strength, ligament laxity and task-specific movements. This is done to rule out any other potential causes of the ankle sprain. Potentially an MRI may be needed to confirm the above findings, however, this is not a necessity.

I have it, what can I do to manage CAI?

The main treatment options for CAI are exercise and usage of external ankle supports. External ankle supports are very useful to help prevent ankle sprains, especially during sporting activities. Exercises that target strength, balance and neuromuscular control are also of benefit to treating this condition. In more severe cases, ankle surgery may be needed to tighten the loosened ligaments, a consultation with an orthopedic surgeon would help to decide if this is needed or not.


When seeing a physiotherapist, they will tailor a specific program based on your goals and activities. Here are some examples of exercises that can be given.

Invertor and Evertor Strengthening: Strengthening exercises especially targeting invertors and evertors of the ankle have found to be an effective form of exercise to help with CAI. The below video shows a demonstration of an exercise for the invertors and evertors with a theraband.

Balance Exercises

1. Single Leg exercise on foam mat whilst throwing PTP reaction ball.

Focus on maintaining balance and catching the ball. The reactive ball challenges you to reach outside your base of support and testing your ability to catch a ball reactively.

2. Y-balance

Another exercise for balance, by reaching outside of your base of support with your feet.

3. Eversion with pull-off press

The purpose of the exercise is to activate the evertors of the ankle in a lengthened position whilst trying to maintain core stability.

These are some of the many exercises that can be provided by a physiotherapist to help manage CAI.

Remember, the advice and exercises provided in this blog are of a general nature only. For your specific condition or injury, please consult with a health professional. If you have any questions, feel free to reach out to our Breathe physiotherapists.

Blog and videos by UQ Physiotherapy student undertaking clinical placement, supervised by principal physiotherapist, Winnie Lu.

Principal Physiotherapist

Souths United Football Club Physiotherapist


Al-Mohrej, Omar, & Al-Kenani, Nader. (2016). Chronic ankle instability: Current perspectives. Avicenna Journal of Medicine, 6(4), 103–108.

McKeon, Patrick O, & Hertel, Jay. (2008). Systematic review of postural control and lateral ankle instability, part I: can deficits be detected with instrumented testing. Journal of Athletic Training, 43(3), 293–304.

Handoll, Helen HG, Rowe, Brian H, Quinn, Kathryn M, de Bie, Rob, & Handoll, Helen HG. (2011). Interventions for preventing ankle ligament injuries. Cochrane Library, 2011(5).

Chinn, Lisa, MS, ATC, & Hertel, Jay, PhD, ATC. (2010). Rehabilitation of Ankle and Foot Injuries in Athletes. Clinics in Sports Medicine, 29(1), 157–167.

196 views0 comments

Recent Posts

See All


bottom of page