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Appl Ergon. 2017 Jan;58:482-490. doi: 10.1016/j.apergo.2016.08.008. Epub 2016 Aug 24.

Effects of milking unit design on upper extremity muscle activity during attachment among U.S. large-herd parlor workers.

Author information

1
The University of Texas Health Science Center at Houston, School of Public Health, San Antonio Regional Campus, TX, USA. Electronic address: david.i.douphrate@uth.tmc.edu.
2
The University of Texas Health Science Center at Houston, School of Public Health, San Antonio Regional Campus, TX, USA.
3
University of Iowa, College of Public Health, Iowa City, IA, USA.
4
New Mexico State University, Dairy Extension, Clovis, NM, USA.
5
Colorado State University, Environmental and Radiological Health Sciences, Ft. Collins, CO, USA.

Abstract

BACKGROUND:

Large-herd dairy parlor workers experience a high prevalence of musculoskeletal symptoms in the upper extremity. The purpose of this study was to evaluate the effect of milking unit design on upper extremity muscle activity during milking unit attachment.

METHODS:

Upper extremity muscle activity was recorded among U.S. large-herd parlor workers (n=11) using surface electromyography. Participants performed several milking unit attachment cycles with each of six milking unit designs. Muscle activity levels were then compared between unit designs.

RESULTS:

Mean muscle activity levels (in %MVE) across milking units ranged from 6.8 to 8.2 for the upper trapezius, 8.2 to 10.3 for the anterior deltoid, 13.8 to 17.2 for the forearm flexors, and 9.9 to 12.4 for the forearm extensors. Pairwise comparisons between milking units did not reveal statistically significant differences in muscle activity levels across milking unit designs. However, a general pattern of higher muscle activity was observed with specific milking units. Milking unit weight, milk tube spread, and teat cup shape may explain differences in muscle activity levels.

CONCLUSIONS:

Milking unit design may influence muscle activity levels among parlor workers. Small reductions in muscle activity associated with milking unit design have the potential to delay the onset of fatigue or development of musculoskeletal health outcomes among parlor workers.

KEYWORDS:

Dairy; Electromyography; Equipment; Milking unit

PMID:
27633245
DOI:
10.1016/j.apergo.2016.08.008
[Indexed for MEDLINE]

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