QUANTITATIVE ASSESSMENT OF THE CONTROL CAPABILITY OF THE TRUNK MUSCLES DURING OSCILLATORY BENDING MOTION UNDER A NEW EXPERIMENTAL PROTOCOL

Objective. A new quantitative technique for measuring the trunk contro l capability/coordination was to be developed in this study. Design. F itts' experimental paradigm was employed to quantify the information p rocessing capacity (bits/s) of the trunk as well as dynamic motor perf ormance such as velocity and acceleration during flexion and extension . Background. The quantification of functional capability of the trunk such as range of motion, strength, and endurance have been used to ev aluate low back pain patient. Especially, dynamic trunk motion during flexion and extension has been studied not only to quantify the severi ty of the low-back impairment but to classify patients. Method. A lumb ar motion monitor was used to record the time series of range of motio n (RoM) and compute the velocity and acceleration of the trunk motion. Twenty male subjects without any back pain in the past 6 months and p revious history of back injury participated. Each subject performed 22 controlled flexion/extension at predetermined RoMs as well as one bal listic trunk flexion/extension at a self-selected RoM. Results. The in formation processing capacity of the trunk among healthy subjects was found to have a mean of 4.23 (SD 1.43) bits/s based on Fitts' law. Als o, the velocity of dynamic trunk motion was measured with a considerab le reduction in intersubject variability when the RoMs were controlled . A short but still accurate experimental protocol was suggested via a series of statistical analyses to provide an objective and easy-to-us e method to evaluate the functional capacity of low-back pain patients . Relevance The information processing capacity may quantitatively rep resent the functional deficit of neuromuscular system of the trunk. Al so, this protocol provides the trunk velocity information with a small er within group variability under controlled RoM. This method is expec ted to increase the sensitivity and specificity in identifying the tru nk performance of healthy subjects and LBP patients without exacerbati ng the injury or pain due to an excessive exertion. Copyright (C) 1996 Elsevier Science Ltd.