Correlation of expertise with error detection skills of force application during spinal manipulation learning.

OBJECTIVE: Most studies on spinal manipulation learning demonstrate the relevance of including motor learning strategies in chiropractic curricula. Two outcomes of practice are the production of movement in an efficient manner and the improved capability of learners to evaluate their own motor performance. The goals of this study were to evaluate if expertise is associated with increased spinal manipulation proficiency and if error detection skills of force application during a high-velocity low-amplitude spinal manipulation are related to expertise. METHODS: Three groups of students and 1 group of expert chiropractors completed 10 thoracic spine manipulations on an instrumented device with the specific goal of reaching a maximum peak force of 300 N after a brief period of practice. After each trial, participants were asked to give an estimate of their maximal peak force. Force-time profiles were analyzed to determine the biomechanical parameters of each participant and the participant's capacity to estimate his or her own performance. RESULTS: Significant between-group differences were found for each biomechanical parameter. No significant difference was found between groups for the error detection variables (p > .05). The lack of significant effects related to the error detection capabilities with expertise could be related to the specificity of the task and how the training process was structured. CONCLUSION: This study confirms that improvements in biomechanical parameters of spinal manipulation are related to expertise. Feedback based on error detection could be implemented in chiropractic curricula to improve trainee abilities in detecting motor execution errors.

Learning spinal manipulation: the effect of expertise on transfer capability.

OBJECTIVE: Transfer capability represents the changes in performance in one task that result from practice or experience in other related tasks. Increased transfer capability has been associated with expertise in several motor tasks. The purpose of this study was to investigate if expertise in spinal manipulation therapy, assessed in groups of trainees and experienced chiropractors, is associated with increased transfer capabilities. METHODS: Forty-nine chiropractic students (fifth- and sixth-year students) and experienced chiropractors were asked to perform blocks of 10 thoracic spine manipulations in 3 different conditions: preferred position and table setting, increased table height, and unstable support surface. Spinal manipulations were performed on a computer-connected device developed to emulate a prone thoracic spine manipulation. Thrust duration, thrust force rate of force application, and preload force were obtained for each trial and compared across groups and conditions. RESULTS: Results indicated that both expertise and performance conditions modulated the biomechanical parameters of spinal manipulation. Decreased thrust duration and increased rate of force application were observed in experienced clinicians, whereas thrust force and thrust rate of force application were significantly decreased when task difficulty was increased. Increasing task difficulty also led to significant increases in performance variability. CONCLUSION: Overall, this study suggests that when instructed to perform spinal manipulation in a challenging context, trainees and experts choose to modulate force to optimize thrust duration, a characteristic feature of high-velocity, low-amplitude spinal manipulation. Given its known association with motor proficiency, transfer capability assessments should be considered in spinal manipulative therapy training.