Developing skilled performance of lumbar spine manipulation

We are writing in regard to the randomized controlled study by Dr John Triano et al.1 As students in the chiropractic field, we are interested in the way that education can be modified to help build competence, effectiveness, and skill in practice. We are encouraged to see people researching methods that may improve the way we are taught the art and science of chiropractic. The information in this article was interesting to us because it examines the difficult process of learning and teaching the art of the chiropractic adjustment.

In the Methods section of the article, we had a difficult time distinguishing clear inclusion and exclusion criteria. We were able to find that disinterest, prior spine surgery, and contraindication to spinal manipulation were part of the exclusion criteria. It was unclear whether the aforementioned comprised the entire list of criteria or if they were simply on the list. The inclusion criteria seemed less clear. We only know that students must be starting in the Texas Chiropractic College. In general, we feel that more information about inclusion and exclusion criteria would be necessary for accurate reproduction of the experiment.

In our appraisal of the article, we also found ourselves wondering if the 2 randomly assigned groups were homogenous. We would have liked to see the mean age, sex, weight, and perhaps education of the individuals involved in this experiment. It is well known that a person’s age and sex determine their body type, and this may play into the biomechanics of adjusting. It would be interesting to know if these factors skewed results by providing groups with significant differences at baseline.

Finally, we would like to discuss the link between the data and the article’s Conclusion. In the Methods section, it was stated that the standard curriculum group (SC) would follow the standard curriculum. The Dynadjust instrument group (DI) was to follow the standard curriculum and, in addition, would rehearse “each of the 3 selected procedures with 10 repetitions of manipulation forces simulating the selected procedure on the Dynadjust instrument.” In the Conclusion section of the abstract, it is stated that, “With quantitative training aids and biomechanical measurement systems, future training programs may be optimized and tested.” This suggestion that training aid instruments could “optimize” training programs seems somewhat presumptuous.

We suggest that the extra rehearsals and not the instrument could have produced the improved skills. In our estimation, the average trimester is 15 weeks in length, and the normal school week is 5 days. Based on this, the students of the DI group rehearsed each of the 3 procedures approximately 750 times (15 weeks × 5 days per week × 10 thrusts per procedure per day). It is therefore impossible to determine whether the improvement was the result of the training aids or the extra practice the DI group had. We would suggest that the experiment be repeated with slight modifications to make the DI group and SC group practice the same number of procedures. In future studies, the SC group could be made to practice each of the 3 procedures 10 times each day without the machine. This would eliminate the natural improvement that could come from 750 practices, thus allowing the researchers to determine the net effect of the machine alone.

We would like to thank the authors for researching methods with which teachers and institutions can be more effective in educating students. We hope that this sort of educational research will continue.