METHODS: This study was reviewed and approved by the Institutional Review Board of the European Institute of Health and Medical Sciences. This was a single blind study of 6 months duration. Thirty volunteers diagnosed with mechanical low back pain or with a history of at least two episodes mechanical low back pain were entered into the intervention group. Another cohort of 28 volunteers, reporting no history of low back pain, were recruited as a control arm. Inclusion criteria limited subjects to between the ages of 20 and 68 years. A blinded evaluator (a podiatrist) performed navicular measurements, calculated percentage navicular drop and measured relaxed weight bearing calcaneal eversion.
RESULTS: There were no statistically significant differences between the groups in the percentage of navicular drop, the initial non-weight bearing height of the navicular, degree of calcaneal eversion, difference in navicular drop bilaterally or difference in calcaneal eversion bilaterally. Calcaneal eversion was shown to have a significant and positive relationship to navicular drop. A fair to moderate relationship was determined in the left foot (r = 0.451) and a moderate to good relationship was determined in the right foot (r= 0.626). Power and effects size was low.
DISCUSSION: Study limitations include the possibility of insufficient statistical power secondary to a weaker than expected effect size that may have influenced study outcomes. In order to enhance power, it is suggested that more stringent inclusion and exclusion criteria exclude control subjects with musculoskeletal pain to the lower limbs (a manifestation of the hyperpronated foot), focus on a chronic low back pain population with a history of a greater number of episodes, and increase the sample size.
This study was originally completed as part of a Master's degree in the Programme of Chiropractic, European Institute of Health and Medical Sciences, University of Surrey, Guildford, Surrey, England. We wish to thank the University of Surrey for its help and support.
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