Some powered hand tools can generate significant vibration at frequencies below 25 Hz. It is not clear whether such vibration can be effectively transmitted to the upper arm, shoulder, neck, and head and cause adverse effects in these substructures. The objective of this study is to investigate the vibration transmission from the human hands to these substructures. Eight human subjects participated in the experiment, which was conducted on a 1-D vibration test system. Unlike many vibration transmission studies, both the right and left hand-arm systems were simultaneously exposed to the vibration to simulate a working posture in the experiment. A laser vibrometer and three accelerometers were used to measure the vibration transmitted to the substructures. The apparent mass at the palm of each hand was also measured to help in understanding the transmitted vibration and biodynamic response. This study found that the upper arm resonance frequency was 7-12 Hz, the shoulder resonance was 7-9 Hz, and the back and neck resonances were 6-7 Hz. The responses were affected by the hand-arm posture, applied hand force, and vibration magnitude. The transmissibility measured on the upper arm had a trend similar to that of the apparent mass measured at the palm in their major resonant frequency ranges. The implications of the results are discussed. Relevance to industry Musculoskeletal disorders (MSDs) of the shoulder and neck are important issues among many workers. Many of these workers use heavy-duty powered hand tools. The combined mechanical loads and vibration exposures are among the major factors contributing to the development of MSDs. The vibration characteristics of the body segments examined in this study can be used to help understand MSDs and to help develop more effective intervention methods.

中文翻译：

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从人的手传递到上臂、肩膀、背部、颈部和头部的振动

一些电动手动工具会在低于 25 Hz 的频率下产生明显的振动。目前尚不清楚这种振动是否能有效地传递到上臂、肩部、颈部和头部，并对这些下部结构造成不利影响。本研究的目的是研究从人手到这些子结构的振动传递。八名人类受试者参与了该实验，该实验是在一维振动测试系统上进行的。与许多振动传递研究不同，左右手臂系统同时暴露于振动以模拟实验中的工作姿势。激光测振仪和三个加速度计用于测量传递到子结构的振动。还测量了每只手掌的表观质量，以帮助了解传递的振动和生物动力学响应。本研究发现上臂共振频率为7-12赫兹，肩部共振频率为7-9赫兹，背部和颈部共振频率为6-7赫兹。反应受手臂姿势、施加的手力和振动幅度的影响。在上臂测量的透射率与在手掌处测量的主要共振频率范围内的表观质量具有相似的趋势。讨论了结果的含义。与行业的相关性 肩颈肌肉骨骼疾病 (MSD) 是许多工人面临的重要问题。这些工人中的许多人使用重型电动手动工具。综合机械载荷和振动暴露是促成 MSD 发展的主要因素之一。本研究中检查的身体节段的振动特性可用于帮助理解 MSD 并帮助开发更有效的干预方法。