Abstract
Objective: To quantify the amount of force orthopedic physical therapists use to perform joint mobility assessment and grades I to IV of joint manipulation of the thoracic spine. Methods: Nineteen physical therapists working in the outpatient orthopedic setting were recruited to participate. The orthopedic physical therapists performed joint mobility assessment and Maitland grades I-IV manipulation in a posterior-anterior direction on the thoracic spine of the same individual. The forces exerted by the physical therapists were measured with the MotionMonitor Manual Therapy system force sensor. Descriptive statistics were performed to determine the mean high and low forces used for thoracic joint mobility assessment and grade I-IV manipulation, and mean time between oscillations for grade I-IV manipulation. Two repeated measures analyses of variance (ANOVAs) were performed to determine if significant differences occurred in mean high force and mean low force (N) between manipulation grades I-IV. A third repeated measures ANOVA was performed to determine if significant differences occurred in time between oscillations (s) in grades I-IV manipulation. Results: The results showed a high amount of variability for both high and low mean forces for joint mobility assessment, and a high amount of variability was observed for the Maitland grades I-IV manipulation as well. The mean high force during assessment was 104.93 N (SD=33.80) and the mean low force was 63.20 N (SD=33.35). Grade I high force of 49.38 + 30.05 N, and grade IV high force of 129.71 + 62.37 N. Grade I low force of 33.33 + 26.07 N, grade IV low force of 84.95 + 59.21 N. Time between grade I oscillations of .78 + .53 seconds, and time between grade IV oscillations of .87 + .75 seconds. A statistically significant difference was found in force (N) between grades I-IV of joint manipulation for both mean high force (F=22.004, df=3, p=.000) and mean low force (F=11.095, df=3, p=.000). There was also a statistically significant difference (F=4.436,df=3,p=.019) in time (s) between oscillations in grades I-IV of joint manipulation. Conclusion: There is a high amount of variability between orthopedic physical therapists for both high and low mean forces used to perform thoracic joint mobility assessment, and Maitland grades I-IV of joint manipulation. Further research is needed to improve clinical standardization of joint assessment and manipulation techniques.