The effect of talocrural joint manipulation on muscle activity of the lower limb, balance, pain and disability in participants with chronic ankle instability syndrome

Abstract

Background and Purpose: Ankle sprain injuries are prevalent in both the sporting and general population and can develop into chronic ankle instability syndrome (CAIS). When this occurs, there is a tendency for the ankle to re-sprain following an acute ankle sprain. Deficits in proprioception and neuromuscular control, specifically of the peroneal muscles, may lead to altered balance and postural stability in patients with CAIS. Recent research suggests that the ankle invertors and plantarflexors are also affected. Joint manipulation has been shown to result in reduced pain and improved foot and ankle functioning in individuals with CAIS, however, the exact mechanism(s) through which joint manipulation brings about these effects is not clear and the field of extremity joint manipulation on arthrogenic muscle inhibition (AMI) is under-investigated. This study aimed to determine the immediate effect of talocrural joint manipulation on postural stability and the muscle activity of the ankle invertors, evertors and plantarflexors by assessing surface electromyography (sEMG) of these muscles during static single-limb postural stability testing. Subjective outcomes of pain and disability were also measured through the use of the foot and ankle disability index (FADI). Methods: This study used a randomized, single blinded placebo controlled pre-test, and a repeated post-test measures experimental design. A sample of 42 participants, with grade I or II CAIS, aged 18-45 years, were randomly allocated into two groups. One group received a long axis distraction talocrural joint manipulation and the other group, a sham manipulation. General pain and disability (FADI), postural stability (Biosway Portable Balance System) and muscle activity (Biopac wireless EMG system) measurements were taken before the intervention. Muscle activity and postural stability were assessed again immediately after the intervention and then again 20 minutes later. Postural stability and muscle activity were measured both with participants’ eyes opened and eyes closed. FADI measurements were taken 24 hours after the intervention. Results: The two groups were comparable at baseline for age, gender, body mass index, pain and disability, postural stability and muscle activity (p > 0.050). An inter-group analysis showed a significant improvement in FADI (p= 0.005) and general pain scores (p= 0.039) when compared to the placebo group post-manipulation. There were no significant changes in the manipulation group for muscle activity and postural stability when compared to the placebo group (p > 0.050). Intra-group analysis showed an overall improvement over time for eyes opened postural stability in the manipulation group (p= 0.040) and decreased fibularis longus muscle activity in the placebo group with eyes open balance testing (p= 0.047) and eyes closed balance testing (p= 0.023). Conclusion: The results of this study showed that talocrural joint manipulation had a positive effect on pain and disability in individuals with CAIS. No significant differences were found between the intervention and placebo groups for limb muscle activity and postural stability. Intra-group analysis showed that the manipulation had a positive effect on eyes-open postural stability performance and that there may have been a trend of an effect of manipulation counteracting muscle fatigue experienced in the fibularis longus of the placebo group. Further investigation to further elucidate the effect of manipulation in CAIS is recommended.