The relationship between leg length inequality and pelvic kinematics

Leg length inequality (LLI) is thought to be clinically linked to pelvis kinematics. Yet, scientific uncertainty exists around the relationship between LLI and pelvis kinematics. This thesis reports on two projects: 1. a systematic review exploring associations between LLI and pelvis kinematics, and 2. a single group biomechanical study that investigates the association between artificially induced leg length inequality and pelvis kinematics using 3-D motion analysis. Participants were measured in upright standing (static) positions during four heel-lift conditions (0mm, 5mm, 9mm, 12mm). Kinematic data for each participant was used to produce two outcome measures 1. Whole pelvis rotations and 2. relative pelvis rotations. For each condition of LLI, means and standard deviations described global and relative pelvis kinematics of participants. A repeated measures ANOVA analysed differences in the population means of the four heel-lift conditions. Post-hoc analyses estimated the effect of heel-lifts, compared to no heel-lift. The review found included studies were at moderate-to-high risk of bias with inconsistent data indicating LLI is associated with pelvis kinematics. The primary study found a relationship between clinically applied heel-lifts and whole pelvis transverse plane rotations. This dissertation challenges existing theories on the relationship between LLI and pelvis kinematics.