Learning Spinal Manipulation: Objective and Subjective Assessment of Performance

The purpose of this study was to investigate associations between objective spinal manipulation therapy (SMT) biomechanical parameters and subjective assessments provided by patients, clinicians, and expert assessors.

Chiropractic students (N = 137) and expert instructors (N = 14) were recruited. Students were asked to perform a thoracic SMT alternately on each other on a force-sensing table while being observed by an expert instructor. Students who performed (clinicians) and received (patients) SMT, and expert instructors, independently scored each SMT performance using visual analog scales. Correlations between these subjective scores and SMT biomechanical parameters were calculated. The following parameters were evaluated: peak force, preload force, thrust duration, and drop in preload force. Spinal manipulation therapy comfort was also assessed by patients, clinicians, and expert instructors.

Results of the study indicate that thrust duration assessed by instructors and patients was the only parameters significantly correlated with the table data (r = .37; P < .001 and r = .26; P = .002). Comfort assessed by clinicians was significantly correlated with their own assessments of thrust duration (r = .37; P < .001) and preload force (r = .23; P = .007), whereas comfort assessed by instructors was significantly correlated with their own assessment of thrust duration (r = .27; P = .002) and drop in preload force (r = -.34; P < .001). Objective biomechanical parameters of performance did not predict perceived comfort.

Overall, the results from the subjective assessments of SMT performance are weakly correlated with objective measures of SMT performance. Only the thrust duration evaluated by expert instructors and patients was associated with scores obtained from the table. Perceived comfort of the procedure seems to be associated mostly with perceived thrust duration and preload characteristics.