• Gudavalli MR

• Association of Chiropractic Colleges / congresses

METHODS: A total of 36 thrusts (double transverse, posterior to anterior) were delivered by the three chiropractors to a mannequin of similar shape and texture to a human. A three-dimensional force transducer was used between the doctor’s hand contact points and the mannequin. A computer and Motion Monitor software (Innovative Sports Training, Chicago, Illinois) was used to collect data at a sampling rate of 1000 samples per second. Each of the three doctors were asked to deliver two hand contact double transverse thrusts to the upper thoracic, middle, and lower thoracic levels. The doctors were instructed to deliver four types of thrusts according to their judgment. These are (i) high force high speed, (ii) high force low speed, (iii) low force high speed, and (iv) low force low speed thrusts. Doctors were not permitted to observe each other delivering thrusts. All the doctors and the technician collecting the data were blinded to the data. The data was exported to a text file and read into a MathCAD (version 11, Math Soft Inc., Waltham, MA). The data was reduced to important thrust characteristics using custom developed MathCAD software program. Biomechanical characteristics of the thrusts in terms of the duration, rate of loading, preload and peak loads were extracted from the data for the three chiropractors. The data was analyzed descriptively using minimum, maximum, average, and standard deviation calculations and comparisons based on these values.

RESULTS: The three clinicians had distinct thrust characteristics. Inferior to superior forces varied from -35N to 99N at the thrusting hand while they varied from -73N to 62N at the stabilizing hand. Lateral forces varied from -88N to 50N at the thrusting hand while they varied from -52N to 41N at the stabilizing hand. Peak loads in the posterior to anterior direction ranged from 146-454N at the thrusting hand, and 148-362N at the stabilizing hand. Durations of the thrust ranged from 119-652 milliseconds. Rates of loading have ranged from 246-2105N/s. The stabilizing hand peak forces were 90% of the thrusting hand peak forces. Low force adjustment force magnitudes were 70% compared to high force adjustment magnitudes. Duration and rate of loading for low speed adjustments were 50% of the magnitudes for the high-speed adjustments.

DISCUSSION: The thrusting hand forces observed were smaller compared to the literature values reported for a single hand contact posterior to anterior thoracic adjustments. This is a first study reporting the hand contact forces at both hand contacts during double transverse adjustments by experienced clinicians. This study provides a system for quantifying the three-dimensional load characteristics of different doctors on a mannequin. Future studies should aim at the training of the clinicians at specific ranges and use of this information in clinical trials on patients to determine the optimal treatment parameters. Improved mannequin development could lead to development of a database for training of students in chiropractic colleges.

ACKNOWLEDGEMENTS: The authors wish to acknowledge the clinicians, Mr. Caelyn Nagle, Mr. Josh Myers, and Ms. Tina Parekh for assistance with this study.

This abstract is reproduced with the permission of the publisher.