Muscle Strength of the Ankle

Definition / Description

Muscle strength is the amount of force a muscle can generate. 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.

Charecteristics

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.
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(e.g., greater recruitment, rate of discharge), increased muscle CSA, changes in muscle architecture, and possible adaptations to increased metabolites, for increased strength.


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

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) Strengthening of weakened muscles is essential to rapid recovery and is a preventive measure against reinjury. All muscles of the ankle should be targeted, including the peroneal muscles. All exercises performed bilaterally.
Continual monitoring of strength is important. Isokinetic strength testing is an accepted method of assessing ankle strength. Also used is a hand-held dynamometry for consistent monitoring of strength performance. (ref 1 level A1)
It is important to understand that each rehabilitation program must be individualized (ref 2)
The use of mental practise during the threatment also results in higher strength gain (ref 5 level A2?)

Strengthening begins with isometric exercises and progresses to dynamic resistive exercises.

Isometric Strength Training
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
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 (ref 2, 3⇒ rubber tubing en 4 richtingen)
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)
4)Eversion
Procedure: Push foot outward (away from the midline of the body)

Toe curls and marble pick-ups
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
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

As the patient achieves full weight bearing without pain, proprioceptive training is initiated for the recovery of balance and postural control (ref 2 en 3)