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Ankle Mobility, Ankle Instability, and Exercises to Strengthen Your Ankle

  • Category: Foot & Ankle
  • Posted On:
  • Written By: Jonathan Kaplan, MD
  1. Complexities of the ankle joint

The ankle is primarily considered a hinged joint in which it only allows one plane of motion, similar to a hinge on a door. This means that the ankle itself is responsible for up and down motion, or what we refer to as dorsiflexion (up) and plantarflexion (down). However, the ankle is truly much more complex than this. It is comprised of three bones: the tibia (shin bone), fibula (bone on the outside of the ankle), and the talus. These bones are held closely together at the angle by over nine ligaments (with many of these ligaments having multiple segments of their own), thereby providing excellent stability. Interestingly, the talus is one of the few bones in the body that has only ligaments attached to it and does not have any tendons attached to it.

In addition to the ankle joint itself, it is important to consider the joint underneath the ankle, which is termed the subtalar joint. This is comprised of the talus and the calcaneus (heel bone). This is important to consider as well as this joint is primarily responsible for the inward (inversion) and outward (eversion) motion that occurs through the ankle and foot. This joint also has its’ own ligaments that provide further stability. Lastly, there is additional motion across the joints just further down from the ankle, termed the transverse tarsal joints, which also provide motion in all planes.

  1. Ankle mobility / Stability

The collective anatomy of the ankle, subtalar, and transverse tarsal joints are important for the overall function, motion, and stability across the ankle. The unique anatomy to the bones around the ankle provide inherent stability, however the complex of ligaments around the ankle are especially important in maintaining stability. The ankle is not as mobile as some of our larger joints, such as the hip, however due to the need for the foot and ankle to move both up and down but also inwards and outwards, there is an innate tradeoff for stability. The primary stabilizers of the ankle are the ligaments around the ankle however the secondary stabilizers are the tendons that cross the ankle joint. This means that when the ligaments are injured, the tendons often have to work harder to maintain stability, thereby putting them at risk for injury as well. Ultimately, instability can occur in most of the joints in our bodies if there is injury to either the bones or the ligaments that maintain this stability. One major reason the ankle may be more susceptible to injury and subsequent instability is due to the complex three dimensional function of these joints in combination with the types of activities we are involved in, both within our day to day life as well as more strenuous / physical activities. Simply put, the foot and ankle are the foundation for our body and are in use with almost all activities of daily living.

  1. Ankle instability

There are multiple different ‘types’ of ankle instability depending on which ligaments are injured. However in general, when we refer to ankle instability it is due to an ankle sprain, in which there is an inversion (inward) ankle injury. When this happens, the ligaments on the outside of the ankle are either stretched or torn. The injured ligaments in this situation are the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). These ligaments specifically prevent the ankle from shifting forward (anteriorly) and inward (inversion), therefore when injured patients are more susceptible to repeat injury. After an ankle sprain, these ligaments will typically heal, however they do not always heal as tight as they should, thereby resulting in an increase in abnormal motion across the ankle and subtalar joints with subsequent instability. I like to use the analogy of a rubber band that is stretched out too much and no longer holds the appropriate tension to function. The secondary stabilizers of the ankle in this situation are two tendons on the outside of the ankle called the peroneal tendons, which may also be inflamed (tendonitis) or torn at the time of injury.

The big question is: why does one person get ankle instability after a sprain while another does not? Ankle instability can occur after a single major sprain or after a series of minor or major sprains. It is estimated that there is some level of instability in anywhere between 5-30% of patients sustaining a major ankle sprain. We believe this large variation to be a result of multiple causes, such as due to variations in individual anatomy, variations in ‘normal’ laxity (how flexible or stiff a patient may be at baseline), severity of injury, alignment of the bones in the foot, and many other factors. Additionally, the types of activities we participate in (IE Basketball) as well as types of shoe-wear (IE high heels or shoes that tilt us outwards) may predispose to an ankle sprain. Some of these factors we can control and others we cannot.

Additionally, ankle instability tends to have a bimodal distribution, meaning it presents in two different patient populations. In younger patients, it may occur as a result of an injury to the ligaments and tendons. However in some older patients, these ligaments and tendons may simply weaken over time resulting in what I would term ‘secondary’ ankle instability (not from a particular injury).

  1. Importance of training and strengthening

As is the case with any activity, the more we adequately train our body, the better it will function. Whether doing sudoku puzzles to improve our cognitive brain function, or practicing free throws to prepare for an upcoming basketball game, practice & training are critical to optimize outcomes. This is especially true for maintaining ankle stability. In truth, improvement of ankle stability is not only dependent on overall ligament and muscle/tendon function, but also our brain function. There is a term called proprioception, which is our mind’s awareness of the body’s given location in space at any particular time. These training regimens work both on the physical function of our ankles but also the mental component as well.

Given that ankle instability can occur from an ankle injury or simply over time as you age, performing an exercise regimen focusing on ankle stabilization can potentially help avoid injuries and issues related to ankle instability. Almost everyone will sustain some form of an ankle sprain in their life. Incorporating an ankle stabilization program into your exercise regimen may help avoid ankle injuries and subsequent development of ankle instability.

In the case of an ankle sprain, we know that we cannot make the ligaments truly ‘normal’ again, however, these stabilization programs are designed to strengthen the muscles and tendons around the ankle thereby reducing the amount of work the ligaments have to do. This helps accelerate a return to baseline activities as well as potentially decrease recurrent injuries. This is evident in that there are improved outcomes with a functional rehabilitation program of controlled support and simultaneous stimulation of the ligaments and tendons compared to an extended period of cast immobilization after an ankle sprain.

  1. Exercises for Ankle Stability

The age-old adage of “If you don’t use it, you lose it” is important to consider. Due to inactivity and changes in our lifestyles as we age, our entire core, lower back, and lower extremities muscles weaken over time. Therefore, prior to elaborating on specific exercises for ankle instability, I try to emphasize the importance of incorporating a consistent core and lower back program into a patients exercises regimen.

Specifically related to ankle stabilization, there are many different variations of ankle stabilization exercises that can be done. When considering a specific program, I try to take into account ease of access to equipment in order to stay consistent with the program. Many of these can be performed with minimal equipment, allowing patients to perform them at home, at a local fitness center, or even while traveling.

I’d like to give recognition to a close friend and colleague of mine, David Rivera, who is a physical therapist based out of Chicago, Illinois as he has helped me develop this home program for my patients. For the repetition exercises we generally recommend 3-4 sets of 10-15 reps approximately 2-4 times per week. For the balance exercises we recommend approximately 30 second intervals with 3-5 reps done on a daily basis.

Some of our favorites include:

  • 4 way ankle strengthening with band: This can be done in the seated position or with the foot hanging off the edge of the bed. Using a resistance band, the foot is taken through a series of resisted motions. The resistance band needs to be adjusted based on each of these motions in order to isolate dorsiflexion (upwards), plantarflexion (downwards), inversion (inward), and eversion (outward). This can be accomplished by either wrapping the resistance band around the opposite foot or around a stationary object, such as the leg of a table.
  • Heel Raises (Single & Double Leg): We will often recommend performing these heel raises in a series of exercises that progress through complexity. Patients should start on a flat surface and using both feet to perform the heel raise. Next, a single leg heel raise should be performed in similar fashion, alternating between sides. Lastly, the double leg followed by single leg heel raise can be performed with the heels hanging off the edge of a surface. The best way to do this is using the lowest step on stairs. It is important to have a hand rail or something to hold on to in order to help control the exercises and protect from injury. These are termed ‘eccentric stretches’ as the calf muscle and Achilles tendon are allowed to stretch while simultaneously contracting these muscles.
  • Single Leg Balance: The patient starts by standing with their feet at shoulder width, hands placed on their hips, and then lifts one leg off the ground. The patient focuses on maintaining head, chest, abdominal, and pelvic position without allowing their pelvis, hips, or lower extremity to tilt. This can be done initially on a stable surface such as a flat floor and for more advance technique performed on a foam balance pad. Additionally for even more complex training this can be done with the eyes closed, however this should not be done until the more straightforward techniques are mastered.
  • Tandem Balance: This involves similar technique to the single leg balance however rather than standing on a single leg, the technique is performed with one foot in front of the other. It should be performed with one foot forward first and repeated with the opposite foot in front in order to ensure equal training on both sides. Similarly, it can be performed first on a stable surface such as the floor followed by a more unstable surface such as a foam pad. It should be performed first with the eyes open and for more advanced training can be done with the eyes closed.
  • Tandem Squats: These involve performing a series of body weight squats (no actual extra weight) focusing on proper technique. We will often have our patients start with their feet at shoulder width and perform a controlled squat. Once this is mastered, the feet can be brought closer together as the more narrow base is harder to perform. Additionally, this is initially performed on a stable surface such as the floor followed by a more unstable surface such as a foam pad. It should be performed first with the eyes open and for more advanced training can be done with the eyes closed.
  • Balance / Rocker Board: There are many variations of exercises using a balance board (sometimes called a wobble board). Typically we will start with having the patient simply stand with both feet equally apart and try to keep all edges of the board from touching the ground. Next, the patients are instructed to use their core, lower back muscles, and lower extremities to try to guide the board in specific directions, with the goal of getting either the front, back, or specific sides of the board to gently touch the ground in a controlled fashion. As this is mastered, other activities can be incorporated, such as placing a tennis ball in the center and trying to keep it from moving or even incorporating various hand dexterity activities while maintaining balance on the board.
  • Bosu Lunges: The bosu ball is a half-rounded rubber ball that is often available at a fitness center. Similar to the balance board, there are many variations of exercises that can be done based on expertise and function. Of note, the basic exercises involve the use of the blue, half-rounded side of the ball while more advanced maneuvers involve the flatter, black side. However in most patients I recommend starting with relatively straightforward lunge exercises.

The first exercise involves placing the front foot on the center of the ball (designated by the rings on the ball) and the backfoot in the standard lunge position. The patient then does approximately 10-15 lunges in this position, focusing on a controlled and guided technique. The feet should then be switched and this should be repeated for an additional 10-15 lunges.

The second exercise is slightly more difficult and involves placing the back foot on the center of the ball and the front foot at an adequate length to perform a lunge. Once positioned, 10-15 lunges should be performed, again focusing on control of speed and position. The feet should again be switched and this should be repeated for an additional 10-15 lunges.

For patients without a history of ankle instability, it is beneficial to perform the exercises at three to four times a week incorporated into an exercise regimen, however in patients with previous ankle sprains or ankle instability it may be necessary to perform at least once a day, if not multiple times throughout a day. Also, in our athletes, it is beneficial to perform these exercises both before and after physical activities. For all of these exercises, proper technique is key not only to optimize outcomes but also prevent injury. Therefore, I will often refer patients to at least one or two sessions of physical therapy so they can be taught a home program to ensure safety and outcomes. Also, there are excellent resources on-line and I often recommend patients use various publicly available video media resources in order to learn the intricacies of these exercises. Additionally, with all these exercises, the more basic exercises should be focused on first and progression to the more complex techniques should not be done until basic techniques are mastered. Lastly, if any of these exercises are causing worsening or consistent pain, they should be discontinued. As is the case with foot and ankle injuries or symptoms, a medical professional should be consulted prior to implementing these programs.

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