Words by Bec Munro

What is ‘normal’ ankle joint dorsiflexion?

Ankle dorsiflexion is movement at the ankle where, if the foot is not fixed to the floor, the foot will move up towards the leg, or if the foot is fixed to the floor (as in gait), the tibia moves forward over the foot.
There is no definitive value in the literature as to the ‘normal’ range of ankle dorsiflexion and this is largely due to the fact that some studies use a weight-bearing assessment of ankle movement while others use a non-weight-bearing assessment. There is however a general consensus that a weight-bearing lunge test is the simplest and most reliable test to assess ankle joint dorsiflexion. A measurement of 10-12 cm of the foot from the wall, or a 35-38 degree angle of the tibia are considered to be minimum measurements needed to allow for ‘normal’ function of the lower leg during gait.

What can restrict ankle joint dorsiflexion?

The most common cause of restricted ankle dorsiflexion is tight posterior muscles, usually the gastrocnemius and soleus.
A bony block may also limit ankle movement. An abnormally shaped talus or an anterior exostosis (abnormal bony protrusion) will potentially block movement of the tibia forward over the talus (the bone in the foot that articulates with the tibia).
A tight joint capsule or tight posterior ligaments (tibiotalar and talofibular) can also limit dorsiflexion.

What happens if I don’t have enough ankle dorsiflexion?

Maggs (2015) has reviewed the literature that examines the effects of reduced ankle dorsiflexion on function of the lower limb. There are 6 main outcomes suggested in the research. 1) decreased knee flexion 2) increased knee valgus (where the knee moves towards the midline of the body) 3) increased pronation of the subtalar joint allows for increased dorsiflexion movement at the midtarsal joint in order to compensate for reduced ankle dorsiflexion 4) increased hip flexion and forward lean of the trunk 5) increased ground reaction force (energy coming up from the ground through the foot during gait) 6) impaired balance.

Several studies have looked for a correlation between reduced ankle dorsiflexion and injury. Two studies (Backman & Danielson (2011) and Malliaras et al (2006)) found a correlation between reduced ankle dorsiflexion and patellar tendinopathy. Willems et al (2005) and Pope et al (1998) were both prospective studies that found subjects with reduced ankle dorsiflexion were at five times the risk of ankle sprain. The research is less clear on the contribution of reduced ankle dorsiflexion to the development of plantar fasciitis. It does however make sense that as the midfoot plantarflexes to compensate the plantar fascia will be placed under strain, and most treatment plans for plantar fasciitis will include an Achilles stretching regime.

How can I increase ankle joint dorsiflexion?

Traditionally a static calf stretch (assuming a stretch and holding it for 20-30 seconds) has been prescribed to improve ankle dorsiflexion range. However a dynamic exercise, such as Mulligan’s ankle mobilisation, is thought to not only increase ankle dorsiflexion range but also reduce stiffness of the movement. The exercise program follows:
o Loop a resistance band around a table leg and then around the leg to be stretched. The band should sit below both malleoli (protruding ankle bones) and act to block forward movement of the talus during the exercise.
o Then perform a lunge where the knee should be moved forward over the toes.
o Two to three sets of 10-12 reps should be performed daily.