Forces applied during manual therapy to patients with low back pain

Background: To date, there is little information available regarding the forces used during mobilization treatment of patients with low back pain (LBP). Objective: This study measured such forces and investigated whether the force characteristics could be predicted on the basis of physical therapist and patient characteristics. Subjects: Ten physical therapists applied a central posteroanterior (PA) mobilization treatment to 80 patients with LBP, providing data on treatment of 123 lumbar levels. Methods: Physical therapists were required to treat their patients while the patients lay on an instrumented couch. This couch has been shown to be highly accurate in its measurement of force in 3 directions (error <2%) and has demonstrated high test-retest reliability (ICC [2, 1], 99% CI = 0.99-1.00). The forces applied by the physical therapists were recorded over a 10-second period. Data on the characteristics of the physical therapists and patients were collected by means of questionnaires. Results: The force used by physical therapists related not only to patient characteristics but also to physical therapist characteristics. Interestingly, current pain intensity and nature of symptoms did not affect the forces used. The overall patterns of the force characteristics were generally consistent with previous studies performed in asymptomatic subjects. However, the magnitude of the force applied and the frequency of each grade used in the present study are relatively higher than in earlier studies. Conclusion: These preliminary data provide some useful quantitative information about the forces used during mobilization treatment of patients with LBP. Also, the force characteristics described here may provide useful data for both teaching and research in manual therapy.