Effect of a 2-week Joint Mobilisation on Range of Motion in Those With Chronic Ankle Instability

Introduction: Injury to the lateral ligament complex of the ankle manifesting as ankle sprains are the most frequently incurred musculoskeletal injury [1]. Up to 70% of those who sustain a single lateral ankle sprain report residual symptoms, including recurrent bouts of instability, additional ankle sprains and reduced functional capacity [2]. These negative antecedents form the primary characteristics of chronic ankle instability (CAI), which although often considered an innocuous injury, has been associated with an increased risk of developing co-morbidities such as post-traumatic ankle osteoarthritis. CAI has been linked to many mechanical insufficiencies including reductions in posterior talar glide and dorsiflexion range of motion (DF-ROM). Joint mobilisation techniques that target the posterior glide of the talus are purported to increase DF-ROM through the restoration of arthrokinematic movements that occur between the talus and ankle mortise. Although joint mobilisations are informed by a conceptual framework of clinical reasoning, there is a lack of consensus within the literature regarding their effectiveness as a clinical technique. Further, there is a paucity of methodologically rigorous research into the interaction between treatment dose and ROM improvements [3]. The purpose of this study was to examine the effect of different treatment durations of a grade IV anteroposterior talocrural joint mobilisation on weight-bearing DF-ROM (WB DF-ROM) during a 2-week treatment intervention.

Methods: Forty-eight female team sports athletes (age = 22.8 ±4.8 years) participated in the study. All participants presented with a history of ankle instability which was confirmed using the Cumberland Ankle Instability Tool (CAIT), where a score of less than 24 was used to indicate the presence of the condition. Participants were randomly assigned to one of three treatment conditions (30 seconds, 60 seconds, or 120 seconds), and received six treatments equally spaced over a 2-week period. WB DF-ROM was measured prior to and immediately following each treatment session using the weight bearing lunge test and knee-to-wall principle. Two-way mixed model ANOVA was used to test for differences in WB DF-ROM between groups. Simple main effects were calculated to determine the difference between treatment groups following each treatment session. Effect size statistics were calculated using Hedge’s g.

Results: Statistically significant interaction effects between the treatment group and treatment session for WB DF-ROM (F (17.042, 306.754) = 6.954, p ≤ 0.001, partial η2 = .279, έ = 0.682) were evidenced (Table 1). A significantly greater improvement in WB DF-ROM was observed in the 120 second treatment group compared to the 30 second group following treatment sessions 1, 2 and 3 (p ≤ 0.001). Longer treatment durations were seen to produce significantly greater improvements in WB DF-ROM than lesser durations following treatment session 2 and 3 (p ≤ 0.001). No significant differences were observed between treatment groups following treatment session 4, 5 or 6 (p ≥ 0.05). Effect size statistics showed that there was a ‘very large’ (g ≥ 1.2) effect for the 60 second treatment group following treatment session 1, and for the 30 second treatment group following treatment session 2. All other effect sizes were ‘huge’ (g ≥ 2.0).

Conclusions: These results indicate that an anteroposterior talar joint mobilisation is able to improve measures of WB DF-ROM in females with CAI regardless of treatment duration, whilst increases in treatment durations confer greater improvements during the first 3 application sessions. Consequently, longer treatment durations should be utilised early on in the treatment process to address ankle range of motion deficits.