An evaluation of therapist's ability to perform graded mobilization on a simulated spine

The purpose of this study was to determine whether physiotherapists could perform posteroanterior passive oscillatory movements (POMs) graded according to Maitland (1986, 2001) on apparatus analogous to the lumbar spine. Ten post-graduate physiotherapists specialising in manual therapy performed the equivalent of grade I to IV posteroanterior POMs on apparatus analogous to the lumbar spine. The displacement and amplitude of each oscillation was recorded at four trials. Considerable overlap was observed between the grades, for both measures. In particular grades I and II overlapped greatly with III and IV. For every grade the contribution to variance due to physiotherapist and due to trial were highly significant ( p =0.000). Further, between 53% and 83% of the variance of the displacement and up to 80% of the variance in amplitude was due to differences between physiotherapists. These percentages were greater for the higher grades. Within a trial physiotherapists showed very little variability. The validity of Maitland's grading system as a tool for measurement and replication between physiotherapists is challenged.