Elsevier

The Spine Journal

Volume 6, Issue 2, March–April 2006, Pages 138-145
The Spine Journal

Clinical Studies
Learning spinal manipulation: the importance of augmented feedback relating to various kinetic parameters

https://doi.org/10.1016/j.spinee.2005.07.001Get rights and content

Abstract

Background context

Spinal manipulation is a widely accepted therapeutic approach in the treatment of back pain. In standard training programs, feedback on student performances is provided by an instructor based on teaching and clinical experience. Systematic study of the type of augmented feedback provided and skill learning is lacking in the literature.

Purpose

The goal of this investigation is to compare the performance of two groups of chiropractic students, one receiving traditional training from experienced instructors, and the other, augmented feedback on specific biomechanical aspects of spinal manipulation therapy using an instrumented manikin.

Study design

Randomized controlled study.

Patient sample

Thirty-one fourth-year students from the Department of Chiropractic of Université du Québec à Trois-Rivières participated in this study.

Outcome measures

Kinetic parameters (force-time curves) of spinal manipulation were evaluated.

Methods

Spinal manipulation parameters were measured before and after a 5-week training period in which one group received standard chiropractic training while a second group received augmented feedback about specific biomechanical parameters of spinal manipulation. For both groups, practice scheduling and time duration were similar and consisted of a weekly practice session of 90 minutes for five consecutive weeks. Both groups had to practice thoracic spine manipulation throughout the training period.

Results

Both groups showed a decrease in peak force applied, with a diminution in the number of trials where a downward incisural point was present in preload force. Participants in the feedback training group significantly reduced their peak force variability and significantly increased their preload force. No significant difference was observed for time to peak force.

Conclusions

The results of this study highlight the merits of practicing with an instrumented manikin or other instrumented training aids. Such a device can provide specific feedback on specific parameters of the task during learning; it can also serve as a tool to assess the progress of students and eliminate the risks relating to repetitive spinal manipulative therapy practice on student colleagues.

Introduction

Spinal manipulation therapy (SMT) is the cornerstone of the chiropractic profession. Among all conservative therapeutic interventions, spinal manipulation is the most commonly used intervention by chiropractors [1], [2]. In all chiropractic teaching institutions, numerous hours are devoted to learning this complex motor skill, and it is considered an important aspect of chiropractic training. Overall, the goal of SMT is to apply force and moment with specific parameters of direction, amplitude, and speed to a joint [3], [4], [5]. To perform SMT, students must learn to coordinate and control segments when delivering a specific force in a very short period of time [6]. Traditionally, chiropractic techniques are taught by asking students to first learn the theoretical aspects of spinal manipulation. This is followed by instructors demonstrating the skill, and students executing the task. According to their training level, students partially or completely perform this skill. Feedback on performance is often provided by the instructor based on his/her teaching and clinical experience. However, as pointed out by Pringle [7], feedback in practical chiropractic training is delivered without considering the large body of literature on motor learning.

Recently, a few authors have addressed issues relating to chiropractic teaching methods and the effects of various types of augmented feedback. Compared with usual training, augmented feedback generates significant and lasting learning effects [8]. Scaringe et al. used a simulator in a thrusting maneuver with two predetermined force levels [9]. Their findings suggest that this type of simulator (a piezoelectric film embedded in a 1-inch-thick rubber padded bag) is a valuable tool to improve the learning of complex motor skills. Triano et al. examined the issue of developing skilled performance in lumbar, thoracic, and cervical spine manipulation [10], [11]. One of their goals was to test a learning strategy that combined rehearsal and quantitative feedback from an instrument measuring the application of axial forces against specific resistance levels. To do so, they measured, using a modified treatment table, the pre- and post-training performance of students while they performed SMT on student colleagues. Their results revealed significant differences between the performances of the feedback group compared with the standard training group, particularly for preload, sagittal, and lateral bend moments. These data were interpreted as supporting training aids to enhance performance and improve learning. In a study in which students were tested and practiced with the “same testing device”, Enebo and Sherwood showed the influence of practice scheduling and type of feedback in learning a high-velocity low-amplitude task with a simulator. The results confirm that variable practice combined with visual feedback was the most efficient combination to improve force production accuracy in a retention task [12].

Few studies have looked at feedback and motor learning in palpation skills [7] and mobilization [13]. Pringle compared the effects of various amounts of verbal feedback to reproduce a targeted force during training and after a retention interval [7]. The results confirmed the guidance hypothesis proposed by Schmidt et al. [14]. Subjects who trained with constant knowledge of result (KR) feedback reduced their errors during practice but manifested poor performance in retention, compared with groups that received intermittent verbal feedback in the training sessions.

In a study by Lee et al. [13], physical therapy students were divided into two groups according to the type of feedback provided in training. One group was taught a spinal mobilization technique in the traditional way (feedback provided by the instructor). The experimental group received visual feedback concerning the applied force and the ideal force for each trial. These results indicated that this type of feedback was associated with a significant improvement in accuracy and consistency of the mobilizing force. Moreover, such differences were present in a retention test conducted 1 week later. The present study focused on the importance of employing current theories of motor learning to increase the retention of motor skills for chiropractic students. As suggested by Triano et al. [10], when learning spinal manipulation, various biomechanical parameters should be targeted individually for specific enhancement. Thus, the goal of the present investigation is to compare the performance of two groups of chiropractic students, one receiving traditional training from experienced instructors, and the other, augmented feedback on specific biomechanical aspects of SMT using an instrumented manikin. A secondary goal of the study is to evaluate if learning procedural manipulative skills with a manikin is as efficient as usual chiropractic training and if some biomechanical aspects of SMT are easier to acquire with this type of training.

Section snippets

Subjects

A total of 31 fourth-year students (mean age 23.8 years, 10 men and 21 women) from the Department of Chiropractic of Université du Québec à Trois-Rivières participated in this study, which was conducted concurrently with their clinical training.

Evaluations

Spinal manipulation parameters were evaluated 1 week before the practice sessions and 1 week after the last practice session.

A manikin used to teach cardiopulmonary reanimation was modified and instrumented with a spring to emulate the resistance offered

Results

Using a t test for independent samples, participant characteristics (Table 1) were compared between the two groups and no significant difference was found (p>.05). Moreover, for all dependent variables, no significant differences were noted at baseline evaluation (p>.05).

Two-way analysis of variance yielded a significant main effect of practice for peak force [F (1, 29)=11.57, p=.002]. The mean (SD) peak forces applied by both groups were 645.8 N (133.9) at baseline and 572.9 N (72.2) at

Discussion

This study was designed to compare the efficiency of standard chiropractic training and augmented feedback training in learning SMT. For peak force, the results indicate a main practice effect with a mean decrease of 72.9 N, which is similar to the trends reported by Triano et al. for thoracic spine manipulations [11]. Thus, all subjects were able to reduce their mean peak force level. This is an interesting outcome that could reflect the ability to modulate force levels with practice according

Conclusion

This study has demonstrated the intrinsic value of an instrument manikin to improve psychomotor skills relating to SMT. The instrumented manikin providing augmented feedback is certainly as valuable as standard training and even more efficient for specific biomechanical parameters of spinal manipulation. Training aids eliminate the risk of negative side effects occurring while students practice repetitive spinal manipulations on one another [25]. However, a manikin cannot recreate the large

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This study was funded by the Fond Institutionnel de Recherche de l'Université du Québec à Trois-Rivières. Nothing of value received from a commercial entity related to this manuscript.

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