Muscle strength of the ankle

Original Editor - Pieter Jacobs

Top Contributors - Pieter Jacobs, Sheik Abdul Khadir, Wanda van Niekerk and Claire Knott  

Definition / Description

  • Muscle strength is the amount of force a muscle can generate. 
  • It is different from the muscle power which is the rate at which the muscle can work effectively.
  • The ability to generate force is necessary for all types of movement.
  • Regaining strength bilaterally is accepted clinical practice and is thought to be important for the prevention of ligamentous injuries at the ankle.


  • Muscle fiber cross-sectional area (CSA) is positively related to maximal force production.
  •  The arrangement of fibers according to their angle of pennation,muscle length, joint angle, and contraction velocity can alter the expression of muscular strength.
  • Force generation is further dependent upon motor unit activation according to the size principle. [1]

Adaptations to resistance training enable greater force generation through numerous neuromuscular mechanisms. Muscle strength may increase significantly within the first week of training, and long-term strength enhancement manifests itself through enhanced neural function, changes in muscle architecture, increased muscle CSA and possible adaptations to increased metabolites, for increased strength.[1]

The magnitude of strength enhancement is dependent on the type of program used and the careful prescription of muscle actions, intensity, exercise selection and order,volume, frequency and rest periods between sets.[1]

Physical Therapy Management

Once ROM is achieved and swelling and pain are controlled, the patient is ready to progress to the strengthening phase of rehabilitation.[2][3][4] (grade of evidence =A) It is essential to strengthen the weakened muscles for a rapid recovery and it is a preventive measure against reinjury. All muscles of the ankle should be targeted, including the peroneal muscles.[2][5][3][4][6](grade of evidence = B)

Performing exercises bilaterally is thought to be imortant for the prevention of ligamentous injuries at the ankle. [2]

Continual monitoring of strength is important. Isokinetic strength testing is an accepted method of assessing ankle strength.[2][6] Also used is a hand-held dynamometry for consistent monitoring of strength performance.[7][2] (grade of evidence =A)
It is important to understand that each rehabilitation program must be individualized [2] (grade of evidence =A)
The use of mental practice during the threatment might be a usefull adjunct to treatment options aimed at increasing muscle strength. [8] (grade of evidence =E)

Strengthening begins with isometric exercises and progresses to dynamic resistive exercises.[2][4]

(grade of evidence = A)

Isometric Strength Training [2]

Resistance is given by an immovable object (wall or floor), the contra lateral foot or manual resistance by the physiotherapist.
Strengthening can be accomplished in a pain-free range of motion.
Frequenty, duration:
Hold muscle contraction for 5–10 s
5–10 repetitions per direction, 3–5 /day 1) Plantar flexion
Procedure: Push foot downward (away from the head)
2) Dorsiflexion
Procedure: Pull foot upward (toward the head)
3) Inversion
Procedure: Push foot inward (toward the midline of the body)
4) Eversion
Procedure: Push foot outward (away from the midline of the body)

Isotonic Strength Training [2][3][5]

Resistance is given by the contralateral foot, rubber tubing, weights or the physiotherapist.
Strengthening can be accomplished in full range of motion and includes concentric and eccentric contractions first in nonweight-bearing position, later in a weight-bearing position 
Frequenty, duration:
Maintain muscle contraction for 4–10 s for concentric and eccentric components
2 sets of 10 repetitions per direction, 3–5 /day

1)Plantar flexion
Procedure: Push foot downward (away from the head)
2) Dorsiflexion
Procedure: Pull foot upward (toward the head)
3) Inversion
Procedure: Push foot inward (toward the midline of thebody)
Procedure: Push foot outward (away from the midline of the body)

Toe curls and marble pick-ups[2]

Strengthening can be accomplished throughout the day at work or at home
Frequenty, duration:
2 sets of 10 repetitions, 3–5 / day
Procedure: 1. Place foot on a towel. Curl toes, moving the towel toward the body.
                 2. Use toes to pick up marbles or other smallobjects.

Toe raises, heel walks, toe walks[2]

Strengthening can be accomplished using the body as resistance in a weight-bearing position
Frequenty, duration:
3 sets of 10 repetitions; progress walking as tolerated

Procedure: Lift the body by rising up on the toes Walk forward and backward on the toes and heels

It is also important to provide home exercises for the patient, this will improve his rehabilitation. The exercises shown here above can be given as home exercises.[5][3][2] (grade of evidence =B)
As the patient achieves full weight bearing without pain, proprioceptive training is initiated for the recovery of balance and postural control. [2][3] (grade of evidence =A)


  1. 1.0 1.1 1.2 Ratamess NA, Alvar BA, Eventoch TK, Housh TJ, Kibler WB, Kraemer WJ, Triplett NT. Progression Models in ResistanceTraining for Healthy Adults Position Stand. American College of Sports Medicine 2009: 687-708 (level of evidence = 1A)
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 Mattacola CG, Dwyer MK. Rehabilitation of the Ankle After Acute Sprain or Chronic Instability. Journal of Athletic Training 2002;37(4):413–429fckLR(level of evidence= 1A)
  3. 3.0 3.1 3.2 3.3 3.4 Chinn L, MS, Hertel J. Rehabilitation of Ankle and Foot Injuries in Athletes. Clin Sports Med. 2010 January ; 29(1): 157–167 (level of evidence =3A)
  4. 4.0 4.1 4.2 Fong DTP, Chan Y, Mok K, Yung PSH, Chan K .fckLRUnderstanding acute ankle ligamentous sprain injury in sports : review. Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology 2009, 1:14 (level of evidence= 1A)
  5. 5.0 5.1 5.2 Fletcher JP, Bandy WD. Clinical Suggestion Unique Positioning for Using Elastic Resistance Band in Providing Strengthening Exercise to the Muscles Surrounding the Ankle.North American Journal Of Sports Physical Therapy. 2007 (2):1:51-54 (level of evidence = 5)
  6. 6.0 6.1 Ürgüden M, KizilayY F, Sekban H, Samanci N, Sibel Özkaynak S, Hakan Özdemir H* fckLREvaluation of the lateral instability of the ankle by inversion fckLRsimulation device and assessment of the rehabilitation program. Acta Orthop Traumatol Turc 2010;44(5):365-377 (level of evidence = 3B)
  7. Stark T, Walker B, Philips JK, Fejer R, Beck R. Hand-held Dynamometry Correlation With the Gold Standard Isokinetic Dynamometry: A Systematic Review. American Academy of Physical Medicine and Rehabilitation 2011;3(5):472-9 (level of evidence = 1A)
  8. Sidaway B, Trzaska AR. Can Mental Practice Increase Ankle Dorsiflexor Torque? Physical Therapy. 2005(85):10: 1053-1060 (level of evidence= 3B)