Relationship between foot pain, muscle strength and size: a systematic review

BackgroundFoot pain is common and disabling and thought to be associated with muscle weakness. Understanding the relationship between pain and weakness may help identify effective treatment targets.ObjectivesTo conduct a systematic review to evaluate the relationship between foot pain and foot muscle weakness, or muscle size as a proxy for weakness.Data sourcesElectronic databases and reference lists were searched for all years to April 2015.Eligibility criteriaFull-text articles were retrieved based on the question 'Does the study evaluate an association between foot pain and foot muscle weakness or size?'Data extraction and synthesisTwo reviewers independently screened eligible studies, extracted data and completed a methodological rating.ResultsEight studies were identified evaluating the relationship between foot pain and foot muscle strength (n = 6) or size (n = 2). Four studies reported a significant relationship between pain and toe flexor force. One study reported a significant relationship between heel pain and reduced forefoot muscle size. One study reported an inconsistent association depending on measurement technique. One study reported no association between pain and hindfoot muscle size. One study reported no association between low to moderate pain and toe flexion force.LimitationsDue to data heterogeneity, no data were pooled for meta-analysis.ConclusionThere is evidence of a significant association between foot pain and muscle weakness when foot pain is of high intensity and primarily measured by toe flexion force. However there is inconsistent evidence that lower intensity foot pain is associated with other measures of foot muscle weakness or size.Systematic Research Registry ID reviewregistry166.