Stimulation of muscles and proprioception after an ankle sprain – Article from Fysioterapeuten

Stimulation of muscles and proprioception after an ankle sprain

Adherence to self-directed exercise after an ankle sprain is very low and reduces the effect of rehabilitation. How can this dilemma be solved?

Optimal effect of rehabilitation after an ankle sprain involves more than 900 minutter with treatment. This is only achieved through self-directed exercise. Adherence to self-directed exercise after an ankle sprain is very low and reduces the effect of rehabilitation. How can this dilemma be solved? 

Incidence of ankle sprains 

Ankle sprains are among the most common musculoskeletal injuries and underscore the need for effective prevention and treatment strategies to reduce the incidence of recurrent sprains and lower the risk of developing chronic ankle instability. The total incidence of ankle sprains in Norway is estimated at 400 per day and 150 000 – 200 000 per year. Studies indicate that up to 70% of the population has experienced at least one sprain during their lifetime. 

More people will experience at least a new ankle sprain within the first 12 months after the initial injury. Thus, a previous ankle sprain is the most important risk factor for subsequent ankle sprains, and more people may develop chronic ankle instability if adequate rehabilitation is not provided. Ankle sprains are often viewed as a minor and self-limiting injury, which means that many do not seek treatment or do not receive sufficient follow-up from healthcare professionals. 

Mechanoreceptors 

Proprioception refers to the body's ability to perceive the position and movement of the joints. This is made possible by mechanoreceptors in muscles, tendons, and ligaments, which provide continuous feedback to the central nervous system about the body's position and movement. Mechanoreceptors are specialized neurons that transmit information about mechanical deformation into electrical signals. Stimulation of these receptors results in reflexive muscle contraction around the joint as a control of movement. In an ankle sprain, the mechanoreceptors in the ligaments become overstretched and therefore have a higher firing threshold. It is therefore crucial for optimal proprioception that other mechanoreceptors in tendons and muscles can maintain the function of positioning the joint until the receptors in the ligaments have returned to normal. 

900 minutes of improvement with exercise 

Rehabilitation after an ankle sprain starts as soon as the acute treatment is over. A meta-analysis showed that exercise interventions significantly reduce the likelihood of recurrent ankle sprains, and that this effect improves with treatment over 900 minutes (OR=0.48, 95% CI 0.37 to 0.63). This corresponds to 15 hours of exercise, which may be difficult to achieve through visits to a physiotherapist alone. Often, a physiotherapist or other therapist is seen once or twice a week, and it will therefore take two months or more to reach 900 minutes of rehabilitation. To achieve the desired effect, a large amount of exercise through self-directed training is absolutely necessary. The challenge with rehabilitation is getting patients to carry out the self-directed exercise. Adherence to self-directed exercise has been shown to be very low. This was discussed, among other places, by Sevild et al. in Fysioterapeuten January 2023, with a summary of previous research. 

Positioning of the foot, stimulation of muscles and proprioception 

I believe patients should exercise more in daily life. A device that pulls the foot into an inversion position could be a solution. This would require the person to actively use the muscles on the outside of the foot to position the foot and ankle in a neutral position during walking. EMG measurements in this context have shown increased stimulation of the muscles laterally on the foot with the intention of stimulating proprioception.

Taping can provide temporary stability, but does not stimulate the muscles in the way active exercise does. Read more here.

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