Immediate effect of two myofascial interventions on navicular position, great toe extension and balance measures in asymptomatic subjects with pronation : placebo controlled

Abstract

Background: Myofascial therapies are widely researched with regards to their effects on pain, disability and range of motion. The benefits of such therapies are attributed to the mechanical changes that myofascial therapies are proposed to have on the fascial and myofascial structures. Breakthrough imaging and laboratory techniques, have allowed the in vivo study of these structures, resulting in new hypotheses regarding the roles that connective tissues might play in proprioception.

Objectives: The purpose of this investigation was to assess the effects of two myofascial therapies, in terms of immediate changes in navicular pronation, great toe extension measurements and balance tests, as indicated by the postural stability (eyes open and closed) and limits of stability tests. Pre-, post-intervention analysis was used to determine if there were significant changes between the groups.

Aims: The myofascial interventions aimed to reduce myofascial restriction and adhesions, within the plantar and crural fasciae’s of individuals with bilateral pronation.

Methods: The study recruited 45 subjects with bilateral pronation (2 or more degrees) and randomly allocated them into a placebo ultrasound, ischaemic compression or myofascial release group. Each subject underwent a case history, physical examination, foot, ankle and knee regional examinations, as well as screened for contraindications. A blinded assistant examiner helped measured and record the baseline measurements for navicular position and great toe extension, using a standard two arm goniometer. The researcher then tested participants for postural stability (eyes open, eyes closed) and limits of stability, on the Biosway Portable Balance System. Subjects were then examined and treated bilaterally, for myofascial restrictions in the foot, lower leg and ankle, related or unrelated to the pronation present. Pre- and post-intervention measurements were recorded within a 20 minute window immediately before and after the relevant intervention.

Statistical Analysis: Repeated measures ANOVA testing was used to compare the rate of change (between pre- and post-intervention measurements) amongst the three groups, and a p-value <0.05 was considered statistically significant. Post hoc Bonferroni adjusted tests were done to compare all pair wise groups, as well as identify trends between groups.

Results and Discussion: The data showed that both myofascial groups, significantly improved in postural stability (eyes closed) overall, post hoc testing showed the ischaemic compression group (p=0.004) and myofascial release group (p=0.031), compared to changes in the placebo ultrasound group.The overall changes were predominantly found in the anterior-posterior axes, with significant improvements in ischaemic compression (p=0.007) and myofascial release group (p=0.053) axes compared to placebo. For the other outcome variables, statistically significant treatment effects were not consistant bilaterally between the groups. Significant (p=0.051) time*group differences for changes in right navicular position. Post hoc testing revealed a borderline significant (p=0.056) improvement in pronation for the myofascial release group in comparison to the ischaemic compression group, which on average got worse. With regards to passive non-weight bearing great toe extension left, significant (p=0.067) improvements for the ischaemic compression group were shown compared to placebo, although this was not consistent for all the great toe extension tests. A borderline significant (p=0.059) time*group effect for postural stability (eyes open) medial-lateral test was obtained. Post hoc Bonferroni adjusted testing showed a non-significant (p=0.063) correlation between the myofascial release group and placebo ultrasound group.

Conclusion: The results of this study, rejects the Null hypothesis for changes in balance measurements and suggests that both myofascial interventions had a significant positive outcome for postural stability, compared to placebo. The postural stability (eyes closed) test gave an indication of positive or negative changes in centre of pressure displacement, about the centre of gravity. It is noted that the sham ultrasound, used as a placebo intervention may have produced a treatment effect and is therefore not a reliable placebo measure for this type of investigation.