Kouji Sakurama

THE COMPARISON OF EMG ACTIVITIES BETWEEN KINAESTHETICS AND NORMAL METHODS DURING PATIENT-HANDLIMG TASKS IN HEALTH CARE WORKERS

INTRODUCTION A high prevalence rate of low-back pain (LBP) is found among health care workers (HCW). Compared to other jobs with heavy lifting tasks and a high prevalence rate of LBP. This may indicate that the risk in connection with a single personal handling situation is higher than the risk in connection with lifting. Several of these risk factors are present in patient-handling tasks. Biomechanical studies have estimated the load on the low back in several patient-handling tasks. Recently, the kinaesthetics method was developed in Germany. This method can reduce the mechanical load of HCW in patient-handling task. Becouse it was the result of our application of the research findings of the science of Feedback Control Theory to problems of human functions. The purpose of present study was to investigate the activities of muscles during kinaesthetics or normal method patient-handling tasks in HCW using electromyography (EMG). METHODS Twelve female subjects volunteered to participate in the laboratory experiments. The mean values ± SD of their heights, weights, and ages were 1.72 ± 0.05 m, 65.2 ± 8.9 kg, 23.2 ± 7.8 yrs., respectively. They received an explanation of the experimental protocol and provided informed consent prior to testing. None of the subjects experienced low-back pain on the experimental day. In a laboratory set-up they performed two different patient-handling tasks in randomized order. The electromyography (EMG) system (WEB-5000, Nihon Kohden, Japan) was used to collect muscle activities from the biceps brachii (BB), triceps brachii (TB), rectus abdominis (RA), erector spinae (ES), hamstrings (HA), vastus lateralis (VL), gastrocnemius (GA). and tibialis anterior. The EMG signals were amplified and recorded by a computer via A/D converter. Before carrying out the tasks, EMG was measured when the subjects performed three different isotonic contractions for arm curl, dead lift and squat. The highest obtained EMG value during these contractions, IEMGmean, was used to normalise the EMG registrations during the tasks. Immediately after completion of each patient-handling task, the subject was asked to rate her perceived physical exertion (RPE) on the low back by answering the question ‘how did you perceive the exertion on the low back’. The Borg CR10 scale (Borg, 1990), where 0 implies ‘nothing at all’ and 10 implies ‘extremely strong’ perceptual intensity, was used for the rating. All values are expressed as means ± SEM. A Student’s paired t-test was used to determination differences between the kinematic variables when using either the kinaesthetics and normal methd. Probability values of p < 0.05 were accepted as being statistically significant. RESULTS AND DISCUSSION Figure 1 shows the change of IEMGmean when the subjects performed kinaesthetics and normal method on patient-handling tasks in randomized order. IEMGmean, in BB, TB, ES, HA, GA and TA were significant difference in kinaesthetics method lower than normal one during patient-handling tasks in HCW. The decrease of the muscular activity of ES could be contributed to the LBP prevention of the nurse. Figure 2 shows change of the Borg CR10 scale when the subjects performed kinaesthetics and normal method on patient-handling tasks in randomized order. The Borg CR10 scale was significantly er kinaesthetics method than normal one. These results indicated that the patient-handling tasks in HCW affect lifting method. The kinaesthetics was a method for contributing to the reduction in the body of the HCW. CONCLUSIONS The kinaesthetics method was decreased EMG activity and muscle fatigue during patients lifting in bed. Thus, in this study kinaesthetics method may be reduced LBP in patient-handling tasks in HCW.