The effect of motor imagery on ankle function and performance in persons with and without a lateral ankle sprain: a systematic review and meta-analysis

Abstract Background: Lateral ankle sprains are highly prevalent and result in tissue damage, impairments of muscle strength, instability and muscle activation. Up to 74% will experience ongoing symptoms after a lateral ankle sprain. Motor imagery might be supportive in rebuilding motor networks or creating new networks to restore impairments such as muscle activation and movement patterns. This systematic review was undertaken to summarize the current body of evidence. Methods: A systematic review with meta-analysis of randomized controlled trials was conducted in healthy participants and participants with a lateral ankle sprain. Movement representation techniques (motor imagery or action observation) in isolation, or in combination with usual care were compared to controls. Any relevant variables related to (self-reported) function and performance were included in the analysis. Results: Nine studies, six examining healthy participants and three examining participants with an acute lateral ankle sprain, were included. All studies were rated with moderate to high risk of bias overall. Quality of the motor imagery interventions differed largely between studies. The results showed a large and significant effect of motor imagery on lower leg strength (SMD 1.47, 95% CI 0.44 to 2.50). Evidence showed a non-significant effect on ankle range of motion (SMD 0.25, 95% CI -0.43 to 0.93), a non-significant on edema (SMD -1.11, 95% CI -1.60 to 3.81), a non-significant effect on the anterior reach direction of the Star Excursion Balance Test (SEBT) (SMD 0.73, 95% CI -0.62 to 2.08), the posterolateral direction (SMD 0.32, 95% CI -0.94 to 1.57), and on the posteromedial direction (SMD 0.52, 95% CI -0.07 to 1.10). The certainty of evidence for the different comparisons was very low. Conclusions: There is a significant, positive effect for motor imagery to improve lower leg muscle strength. The certainty of evidence was however low. The effect on balance, range of motion and edema was uncertain, non-significant and of very low certainty. Systematic review registration: PROSPERO CRD42021243258.