Background Dairy production in the U.S. is moving towards large-herd milking operations resulting in an increase in task specialization and work demands. Large-herd dairy parlor workers experience a high prevalence of musculoskeletal symptoms in the upper extremity. The purpose of this study is to evaluate the effects of an alternative teat scrubber (TS) cow preparation method on upper extremity muscle activity among large-herd parlor workers, as well compare to muscle activity associated with conventional manual milking tasks. Methods Upper extremity muscle activity was recorded among U.S. large-herd parlor workers (n = 15) using surface electromyography. Participants performed multiple task cycles, using both conventional and TS methods. Muscle activity levels were then compared across conventional manual and TS milking tasks. Results Conventional manual milking tasks of dip, strip and wipe were associated higher muscle activity levels of the upper trapezius and anterior deltoid. Biceps muscle activity was greatest during teat dip and wipe. Forearm flexor and extensor muscle activity was greatest during teat wipe and dip. The TS system resulted in more desirable anterior deltoid EMG profiles, and less desirable biceps, forearm flexor and extensor profiles. Conclusions Results suggest that the TS system is effective in reducing anterior deltoid muscle activation levels. The TS system also appears to result in increased biceps, forearm flexor and extensor muscle activation levels. Increases in muscle activation levels could be offset by reduced repetitiveness resulting from three conventional manual milking tasks being replaced with one TS task. Relevance to industry If parlor production requirements (e.g., quality and onsistency) are maintained while simultaneously reducing cumulative muscle loading and worker fatigue, then TS use should be considered in milking parlor operations.

中文翻译：

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新型乳头准备系统对美国大型奶牛场工人上肢肌肉活动的影响


背景 美国的乳制品生产正在转向大群挤奶操作，导致任务专业化和工作需求增加。大群奶牛场工人上肢肌肉骨骼症状的患病率很高。本研究的目的是评估替代性乳头洗涤器 (TS) 奶牛准备方法对大群挤奶室工人上肢肌肉活动的影响，并与传统手工挤奶任务相关的肌肉活动进行比较。方法 使用表面肌电图记录美国大畜群客厅工人 (n = 15) 的上肢肌肉活动。参与者使用传统方法和 TS 方法执行多个任务循环。然后比较传统手工挤奶任务和 TS 挤奶任务的肌肉活动水平。结果 浸入、剥离和擦拭等传统手动挤奶任务与上斜方肌和前三角肌的较高肌肉活动水平相关。二头肌活动在乳头浸洗和擦拭过程中最为活跃。擦拭乳头和浸入乳头时，前臂屈肌和伸肌活动最为活跃。 TS 系统产生了更理想的前三角肌肌电图轮廓，以及不太理想的二头肌、前臂屈肌和伸肌轮廓。结论 结果表明 TS 系统可有效降低三角肌前束的激活水平。 TS 系统似乎还可以提高二头肌、前臂屈肌和伸肌的激活水平。肌肉激活水平的增加可以通过将三项传统手动挤奶任务替换为一项 TS 任务而减少重复性来抵消。与行业的相关性 如果客厅生产要求（例如、质量和一致性），同时减少累积肌肉负荷和工人疲劳，那么在挤奶厅操作中应考虑使用 TS。