title: Reliability and minimal detectable change of gait kinematics in people who are hypermobile.
abstract: OBJECTIVE
  To evaluate intra- and inter-session reliability of gait data in hypermobile and normal adults, and from this, determine the minimum detectable change (MDC) through 3D gait analysis (GA) measurement.
  
  
  METHODS
  Thirteen people with normal flexibility (Beighton score 0.82 ± 1.2) and 14 hypermobile people (Beighton score 5.6 ± 1.6) completed three separate GA sessions. Lower limb joint kinematics were recorded in three planes of motion. Intra- and inter-session variability was calculated and compared using single factor ANOVA. MDC at 95% confidence level was calculated for the hypermobile cohort.
  
  
  RESULTS
  There was no significant difference between hypermobile and normal flexibility adults in intra- or inter-session variability for any parameters measured. For both groups, mean intra-session variability was under 2.0° for all joints in all three planes. Inter-session variability was greater; sagittal plane joint angles were most reliable, showing less than 3.0° variability for all joints. Frontal plane variability was below 3.5°. Highest variability was seen in internal/external rotation angles, with hip, knee and ankle showing 4.6°, 5.1° and 3.2° variability respectively. These reliability values are reflected in MDC results, with pelvis and sagittal plane joint angles showing the lowest MDCs.
  
  
  CONCLUSIONS
  In hypermobile people, 3DGA kinematic parameters are repeatable. Hypermobile people's joint laxity does not affect variability of their kinematic gait analysis measures. The results will help guide future clinical trial design; future work should ensure that differences expected to be observed are measurable, and exceed the MDC for a given parameter.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK. Electronic address: a.bates13@imperial.ac.uk.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Bates
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: Alison H
authors.initials: AH
authors.lastname: McGregor
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, UK; Department of Physiotherapy, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Alexander
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D015203:Reproducibility of Results
keywords: Gait; Hypermobility; Joint hypermobility syndrome; Minimal detectable change; Reliability