Effects of visual feedback on manipulation performance and patient ratings.

OBJECTIVE: This study examined the explicit targeted outcome (a criterion standard) and visual feedback on the immediate change in and the short-term retention of performance by novice operators for a high-velocity, low-amplitude procedure under realistic conditions. METHODS: This study used a single-blind randomized experimental design. Forty healthy male (n = 26) and female (n = 14) chiropractic student volunteers with no formal training in spinal manipulative therapy participated. Biomechanical parameters of an L4 mammillary push spinal manipulation procedure performed by novice operators were quantified. Participants were randomly assigned to 2 groups and paired. One group received visual feedback from load-time histories of their performance compared with a criterion standard before a repeat performance. Participants then performed a 10-minute distractive exercise consisting of National Board of Chiropractic Examiners review questions. The second group received no feedback. An independent rating of performance was conducted for each participant by his/her partner. Results were analyzed separately for biomechanical parameters for partner ratings using the Student t test with levels of significance (P < .01) adjusted for repeated testing. RESULTS: Expressed in percent change for each individual, visual feedback was associated with change in the biomechanical performance of group 2, a minimum of 14% and a maximum of 32%. Statistical analysis rating of the performance favored the feedback group on 4 of the parameters (fast, P < .0008; force, P < .0056; precision, P < .0034; and composite, P < .0016). CONCLUSION: Quantitative feedback, based on a tangible conceptualization of the target performance, resulted in immediate and significant improvement in all measured parameters. Newly developed skills were retained at least over short intervals even after distractive tasks. Learning what to do with feedback on one's own performance may be more important than the classic teaching of how to do it.

Procedural skills in spinal manipulation: do prerequisites matter?

BACKGROUND CONTEXT: Spinal manipulation has undergone a resurgence of interest. Developing evidence suggests a relationship between safety, skill and clinical outcome. Training programs are variable and range from extensive formalized curricula to weekend seminars and individual demonstrations. Systematic study of a relationship between prerequisites and skill development has not been conducted. PURPOSE: This project evaluated programmatic differences in prerequisites of students during their training for spinal manipulation with respect to quantitative biomechanical evidence of procedural control and skill of performance of a novel task. STUDY DESIGN/SETTING: The research used an experimental design comparing two cohorts involved in separate training programs at different institutions that had distinguishing characteristics in methods of prerequisites to manipulation training. METHODS: A common manipulation procedure (L4 mamillary push [L4MP]) was chosen as a standard test maneuver. Performance of the procedure on initial effort by two cohorts of students (n=38 vs n=39) entering into training for lumbar spine procedures was measured. Comparisons were made based on quantitative biomechanical parameters to assess control and skill. Results were compared with a cohort of experts as a reference standard. RESULTS: Significant differences were observed between the performance measures of the two cohorts. The more skilled performance group was more similar to the expert reference standard than was the lesser skilled group. CONCLUSIONS: The duration, extent and content of prerequisites for learning the dynamic and complex manual skills for spinal manipulation can significantly influence the level of skill attainment even early in the course of training.

Biomechanical measure validation for spinal manipulation in clinical settings.

OBJECTIVE: To evaluate the validity and fidelity of the Leander 900 Z Series treatment table (Leader Health Technologies Corporation, Port Orchard, Wash) with an imbedded AMTI force plate (Advanced Mechanical Technology, Inc, Watertown, Mass) as a sensing system and to test its ability to quantify small, statistically significant changes in biomechanical parameters of spinal manipulative therapy (SMT). SETTING: Technology bench testing and Chiropractic College. METHODS: Complex forces and moments were applied to the modified treatment table, including standardized static and dynamic loads and those exerted by chiropractic students when delivering spinal manipulative therapy. Manipulation data was postprocessed by a second-order Butterworth filter with a 5-Hz cutoff frequency. Changes in lumbar spinal manipulative therapy procedures performed by chiropractic students were digitally recorded using the sensing system at approximately 1-month intervals throughout the course of a trimester of training. RESULTS: The system frequency response remains relatively consistent over the interval of test loads from 89 N to 222 N and from 53 nm to 133 nm with fundamental frequencies 5.9 Hz and higher. Changes in biomechanical parameters, including peak amplitude, slope, and duration over time and training, were observed in student chiropractic manipulations. Results show a minimum of 18% (P =.0723) increase during interval 1 in mean peak amplitude and slope parameters. Only a slight (3%) mean reduction of the procedure duration was seen. CONCLUSIONS: The results support the fidelity of the sensing system and its ability to quantify small, statistically significant changes in biomechanical parameters. With this type of instrumentation, it is feasible to assess the skill of chiropractic physicians performing spinal manipulative therapy.

Quantitative feedback versus standard training for cervical and thoracic manipulation.

OBJECTIVE: To quantify elements of spinal manipulation therapy performance and to test the strategy of combined rehearsal and quantitative feedback as a means of enhancing student skill development for cervical and thoracic manipulative procedures. DESIGN: Randomized, controlled study. SETTING: Chiropractic college. SUBJECTS: Thirty-nine chiropractic student volunteers entering the manipulation technique training course. METHODS: Student performance of cervical and thoracic spinal manipulation therapies were quantified at the beginning, middle, and end of a trimester using a Leader 900 Z series manipulation table (Leader International, Port Orchard, Wash) embedded with an AMTI force plate. Passive loads acting through the targeted (C2 or T7) functional spinal units were estimated using inverse dynamics. Participating students rehearsed the index transverse (C2) and single pisiform-transverse (T7) procedures following either the standard curriculum alone or a modified curriculum adding the Dynadjust Instrument training aid (Labarge, Inc.), as assigned on a randomized basis. Student t and chi-square tests were used to explore and describe biomechanical parameter changes over time as the semester progressed. RESULTS: Significant changes in performance between the standard curriculum and modified curriculum (with the Dynadjust) were observed for several, but different, biomechanical parameters of cervical and thoracic procedures. CONCLUSION: This project used a rehearsal program that provided quantitative feedback on an empirically defined schedule that was self-administered by the student. Results demonstrated significant changes in performance of spinal manipulation by students using the Dynadjust Instrument versus those who did not. Using quantitative feedback provided from training aids and biomechanical measurement systems, future training programs may be optimized and tested.

Developing skilled performance of lumbar spine manipulation.

OBJECTIVE: To quantify elements of spinal manipulation therapy performance and to test the strategy of combined rehearsal and quantitative feedback as a means of enhancing student skill development. DESIGN: Randomized, controlled study. SETTING: Chiropractic college. SUBJECTS: Thirty-nine chiropractic student volunteers entering the manipulation technique training course participated after providing informed consent. METHODS: Student performance of lumbar spinal manipulation therapy was quantified at the beginning, middle, and end of a trimester with a manipulation table imbedded with an AMTI force plate. Loads acting passing through the L5/S1 functional spinal unit were estimated by inverse dynamics. Participating students rehearsed the mamillary push, diversified procedure following either the standard curriculum alone or a modified curriculum adding a training aid as assigned on a randomized basis. Student's t and chi(2) tests were used to explore and describe biomechanical parameter changes over time as the semester progressed. RESULTS: Significant changes in performance between the standard curriculum and modified curriculum were observed in several biomechanical parameters. CONCLUSION: The reported project used a rehearsal program defined empirically and was self-administered in practice by the student. Results demonstrated significant changes in performance of spinal manipulation by students using the training aid instrument versus those who did not. With quantitative training aids and biomechanical measurement systems, future training programs may be optimized and tested.