Department of Health Sciences of the University of Milano and the International Centre for Rural Health at San Paolo University Hospital , Milan , Italy.
Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA.
Front Public Health. 2016 Jun 30;4:141. doi: 10.3389/fpubh.2016.00141. eCollection 2016.
Commercial cow milking tasks, regardless of dairy size, have been documented in many regions of the world as strenuous work requiring high muscular effort, awkward positions, and task repetition. Large-herd dairies are common in the U.S., while Europe historically has mostly small-herd dairies. The objective of this study was to compare the upper limb muscle activity during milking tasks between workers at large-herd U.S. dairies and small-herd Italian dairies. This is the first international study directly comparing upper limb muscle activity among dairy workers from different countries using identical methods.
Data were collected at 6 large-herd dairies in the U.S. region of Colorado and at 21 small-herd Italian dairies in the Lombardy region. Surface electromyography (sEMG) from the trapezius, anterior deltoid, biceps brachii, wrist flexors, and wrist extensors muscles was recorded from all participating workers (N = 65). Electromyography data were normalized to functional maximum voluntary contractions. Anthropometric measurements were also recorded.
Upper limb muscle activity was generally greater among workers in the large-herd U.S. dairies compared with small-herd Italian dairies. The amount of muscular rest as a percent of the work time was significantly greater among large-herd U.S. dairy workers.
The differences revealed in sEMG and percent muscular rest among workers from the U.S. and Italy are likely due in part to differences in work processes adopted by fast-paced industrialized large-herd dairies compared with the slower, but sustained work processes performed at small-herd dairies.
在世界许多地区,商业奶牛挤奶任务都被记录为一项艰苦的工作,需要高强度的肌肉用力、别扭的姿势和任务重复。美国的大型奶牛场很常见,而欧洲历史上大多是小型奶牛场。本研究的目的是比较美国大型奶牛场和意大利小型奶牛场工人在挤奶工作中的上肢肌肉活动。这是第一项使用相同方法直接比较来自不同国家的奶牛场工人上肢肌肉活动的国际研究。
数据采集于美国科罗拉多州的 6 个大型奶牛场和意大利伦巴第地区的 21 个小型奶牛场。来自所有参与工人(N=65)的斜方肌、三角肌前束、肱二头肌、腕屈肌和腕伸肌都记录了表面肌电图(sEMG)。肌电图数据被归一化为功能最大自主收缩。还记录了人体测量学测量值。
与小型意大利奶牛场相比,美国大型奶牛场的工人上肢肌肉活动通常更大。美国大型奶牛场工人的肌肉休息时间占工作时间的百分比明显更大。
美国和意大利工人之间的 sEMG 和肌肉休息百分比差异可能部分归因于工业化大型奶牛场采用的工作流程与小型奶牛场较慢但持续的工作流程之间的差异。