Evaluation of upper body kinematics and muscle activity during milking attachment task

- Milking is a physically demanding task that involves high muscular load and repetitive arm elevation.
- Lower udder height results in greater trunk bending and back/neck muscle activity.
- Milking with udder at or above the shoulder level may help reduce back/neck strain.
- Parallel style parlor may be more physically demanding than herringbone milking.

The objective of the study was to evaluate the effects of udder height on upper body kinematics and muscle activity during a simulated attachment task in a parallel parlor set up, and the effects of udder access method (back or side) on the task biomechanics. Twenty males performed the task under conditions that simulated three udder heights and two udder access methods. The muscular load and kinematics during the task confirmed that milking is a physically demanding task. Trunk flexion angle increased with decreasing udder height, and the erector spinae activation was higher when the udder was below shoulder height compared to at or above. Compared to accessing the udder from side of the cow (herringbone parlor style), accessing from behind (Parallel parlor style) was associated with lower trunk flexion, greater shoulder horizontal adduction, lower shoulder elevation, and greater anterior deltoid activation. Milking in herringbone parlor style and with the udder at or above shoulder level may help reduce strain on the trunk/neck.