A validation study of devices designed to reduce loads in provision of care: whether these assistive devices are used, or not, and whether work posture is appropriate or not.

Our country already faces an aging society, but many care workers suffer from work-related musculoskeletal disorders and assistive devices have not been adopted in care-work sites. In order to evaluate the effectiveness of assistive devices, we conducted a study on care work-load; whether the assistive devices are used or not, and whether work posture is appropriate or not, on five female healthcare workers by measuring surface electromyography (SEMG) of biceps brachii, the trapezius (upper extremity) and lumbar paraspinals between L3 and L4 (low back), and the trunk inclination angle (TIA). Moreover, subjective evaluations both by the caregivers and also the care receivers were verified. The caregivers were asked to rate perceived exertion using the Borg scale and the care receiver was asked to rate dissatisfaction. Work condition 1: Repositioning of a supine patient towards the head of bed. Work condition 2: Transferring a patient from sitting on the bed to sitting in a wheelchair. Under the two work conditions there were five set tasks in which subjects used or did not use the assistive devices and worked with or without the appropriate procedure and posture. The representative value adopted was the 95 percentile value. SEMG: Under both work conditions and at all measurement sites, we observed the statistically significant effectiveness of the appropriate procedure and posture as compared to manual handling. When the assistive devices were used improperly, or in work with low bed height, there was no reduction in workloads on the upper extremities. TIA: In both work conditions we observed statistically significant effectiveness of the appropriate procedure and posture as compared to not only manual handling but also working with improper assistive devices and with low bed heights. Findings of the subjective evaluations: The caregiver's perceived exertion and care receiver's dissatisfaction, showed statistical significance in satisfaction with the appropriate procedure and posture as compared to manual handling. Therefore, to reduce workload, and prevent work-related musculoskeletal disorders of caregivers, it is necessary not only to provide assistive devices but also to supervise the proper procedures and work postures and to improve the work environment.