I. Description of Motion:
Inversion occurs at the subtalar joint, it is the action of bringing the foot to midline. (1) The normal available passive range of inversion is 40 degrees, an average of about 17 degrees is needed for normal gait during toe off. (2,3) Primary inverters are tibilais anterior and tibialis posterior, innervated by the deep fibular (L4, L5) and tibial nerve (L4, L5) respectively. (1)
II. Mobilizing – Increasing Range of Motion:
To increase inversion range of motion you must stretch the legs everter’s, eversion is the action of bringing foot away from midline. Everters of the leg are: fibularis longus and fibularis brevis, which are both located in the lateral compartment of the leg. Fibularis tertius also assists with eversion. (1)
When stretching everter’s patient should feel a stretch on their lateral ankle. Patients should hold each stretch for 30 seconds, and repeat the stretch 3 times. Patients should do their stretches twice a day.
• For the first stretch to increase inversion range of motion patient will cross ankle over opposite knee, and pull foot into inversion, hold for 30 seconds. Patient should feel stretch on lateral ankle
• For the second stretch to increase inversion range of motion patient place foot foam roller and bring foot into inversion hold for 30 seconds patient should feel stretch on lateral ankle
• The same muscles that limit inversion, also help assist with plantar flexion, so a dorsiflexion stretch may also help increase inversion. You can stretch these muscles by instructing patient to stand facing a wall with the foot you would like to stretch back, then lean into the wall while keeping the back foots heel down and bending both knees. Patient should feel stretch in back of the calf.
III. Indications for Stretching:
Most common conditions/indications that are supported by literature that require mobilizing or stretching: (4)
• Gentle stretching for an acute ankle sprain (http://morphopedics.wikidot.com/lateral-ankle-sprain)
• After immobilization (cast, walking boot)
• After fracture of ankle
Start the irritable, acute, or very weak patient with isometric exercises:
• Patient will place medial edge of foot against a stabilized structure and press foot medially into the structure- isometrically contract inverters, hold for 10 second, and repeat 5 times
• Seated patient will place feet on both sides of ball and bring both feet into inversion pressing against ball, and hold for 3 seconds, repeat 5 times
In the exercise below, you may progress the patient by increasing the resistance by using the next level band:
• Inversion with theraband: Pt will sit with legs crossed, wrap the theraband around the stabilizing foot, and place therabnad on exercising foot, then bring foot into inversion 10 times for 1 set
Here patient is started with active range of motion exercise, then progressed to stability exercises utilizing a ½ foam roller:
• Patient will stand with 1 foot on half a ½ foam roller, bringing foot into supination and pronation. Patient will do this for 30 seconds, 3 times, twice a day.
• To progress patient will single leg balance on the ½ foam roller for 10 seconds, 3 times, twice a day.
• For the final progression patient will balance in single leg stance and come into yoga pose warrior 3. Perform 3 sets of 10 twice a day.
V. Potential Clinical Syndromes or Etiologies: (4,5)
Here are some common clinical syndromes that indicate strengthening of the inverters:
• Preventing ankle injuries before any pathology present
• Posterior tibial tendon dysfunction
• After sprain
• After immobilization
• After fracture of ankle
• Plantar fasciitis (http://morphopedics.wikidot.com/plantar-fasciitis)
• Tibial nerve entrapment due to hypermobile subtalar joint
VI. References and Additional Web Based Resources:
1. O'rahilly M. Dartmouth Edu. Chapter 17: the foot and ankle. 2008. Available at http://www.dartmouth.edu/~humananatomy/part_3/chapter_17.html. Accessed December 6, 2014.
2. Luke A. UCSF Department of Orthopedic Surgery. Ankle Physical Examination. 2014. Available at http://orthosurg.ucsf.edu/patient-care/divisions/sports-medicine/conditions/physical-examination-info/ankle-physical-examination/. Accessed December 6, 2014
3. Moriguchi CS. Ankle movement during normal gait evaluated by electrogoniometer. Revista Brasileira de Fisioterapia [1413-3555]. Available at http://www.scielo.br/pdf/rbfis/v11n3/a06v11n3. Accessed December 6, 2014.
4. Brody LT, Hall CM. Therapeutic Exercise, Moving Toward Function. Lippincott Williams & Wilkins; 2011.
5. American Acadamey of Orthopedic Surgeons. Ortho info. Posterior tibial tendon dysfunction. 1995. Available at http://orthoinfo.aaos.org/topic.cfm?topic=a00166. Accessed December 6, 2014