McKenzie lumbar classification: inter-rater agreement by physical therapists with different levels of formal McKenzie postgraduate training.

Study Design: Inter-rater chance-corrected agreement study.

Objective: The aim was to examine the association between therapists' level of formal precredential McKenzie postgraduate training and agreement on the following McKenzie classification variables for patients with low back pain: main McKenzie syndromes, presence of lateral shift, derangement reducibility, directional preference, and centralization.

Summary Of Background Data: Minimal level of McKenzie postgraduate training needed to achieve acceptable agreement of McKenzie classification system is unknown.