The goal of Ankle Flex is to restore functional and symmetrical range of motion in both ankles that is appropriate for the individual.

Ankle Flex’s patented technology has been developed by Physical Therapist Esther Smith, DPT, Cert. MDT. Esther has learned from her own ankle injuries and 13 years of clinical experience that even a simple ankle sprain or being in an ankle boot following a fracture can cause dorsiflexion loss. She created Ankle Flex because the standard home exercise protocols to restore ankle mobility were limited.

The ankle joint needs two directions of force in opposite directions to restore normal dorsiflexion following injury. The weight bearing mobilization with movement that Ankle Flex provides mimics the manual therapy technique used by PTs. It combines a pull force to the distal leg (posteroanterior) through the calf cuff while simultaneously stabilizing the foot and talus on the foot plate.

What is ankle dorsiflexion?

The front-to-back (sagittal) plane of movement, which is critical for running, walking, squatting, skiing, climbing and more.

Having limited ankle dorsiflexion (less than 10-15 degrees in one or both ankles) could show up as an early lift of the heel when walking uphill or squatting or in difficulty going straight down steps without making subtle compensations such as overpronating the foot to make up for the lack of hinging at the ankle joint.

These subtle compensations lead to local foot and ankle problems like hammer toes, bunions, tendonitis, plantar fasciitis, fallen arches and chronic ankle sprains. Eventually, we might change how we walk and perform daily activities causing potential upstream pain complaints at the knees, hips, and spine.

Why do some people have limited ankle dorsiflexion?

Limited ankle flexion occurs following ankle sprains and ankle injuries that require an ankle boot, cast or splint. Ankle dorsiflexion loss can also occur with tight calf muscles, stiff ankle joints, toe-walking and many other conditions. 

An ankle injury can impede dorsiflexion long after the injury heals.

Is a stiff ankle limiting your ability to move freely? Take the Knee-To-Wall Test

Typical ankle dorsiflexion is anywhere from 15 to 30 degrees of forward bending while bearing weight, depending on influences like genetics, injury history, and use patterns. You can measure yours with a simple knee-to-wall test.

Test instructions

  • This test is performed facing a wall using a standard tape measure with centimeter measurements. Place the tape measure on the floor perpendicular to the wall, with the zero measurement at the base of the wall. Kneel down facing the wall and place one foot on the tape measure, adjusting so that the big toe is on the tape measurement lines. The leg not being tested remains in a kneeling position.

  • Place your foot in such a way that an imaginary line drawn through the heel and big toe are aligned on the tape measure on the floor. Furthermore, an imaginary vertical line is drawn on the wall in line with the tape measure. Lunge forward until your knee touches the wall (vertical line). Keep the heel in contact with the floor at all times and keep your pelvis straight and level. Move your foot away from the wall until the knee can only make slight contact with the wall while the heel remains in contact with the floor. This placement puts the ankle joint in maximal dorsiflexion.

  • Record the maximum distance from the wall to the tip of the big toe. Measure the distance in centimeters (cm) with each centimeter corresponding to approximately 3.6° of ankle dorsiflexion. Measure both ankles and determine if there is an asymmetry or loss of dorsiflexion. For example, a reading of 2 centimeters equals 7.2 degrees of dorsiflexion, which means that the ankle has limited dorsiflexion. If you determine that you have less than 10-15 degrees or you have asymmetric dorsiflexion between sides you could benefit from Ankle Flex!