Reliability and minimal detectable change of the 'Imperial Spine' marker set for the evaluation of spinal and lower limb kinematics in adults.

The 'Imperial Spine' marker set was used to assess relative peak angles during gait and STS tasks using the minimum recommended sample size (n = 10) for reliability studies with minimum Intraclass Correlation Coefficient (ICC) of 0.70, optimum ICC 0.90 and 9 trials replicated per subject per task. Intra- and inter-tester reliability between an experienced and inexperienced user was examined. ICC, mean, standard error (SEM), Bland Altman 95% limits of agreement (LOA) and MDC were computed. ICC values demonstrated excellent intra- and inter-tester reliability in both tasks, particularly in the sagittal plane (majority ICCs > 0.80). SEM measurements were lower in gait (0.8-5.5°) than STS tasks (1°-12.6°) as were MDC values. LOA demonstrated good agreement. The 'Imperial Spine' marker set is reliable for use in healthy adults during functional tasks. Future evaluation in patients is required.