Ergonomic evaluation of long–shafted tools used in horse stables: the effects of shaft length variation and work technique on working posture

This study examined the physical demands involved in manual manure handling in horse stables when using two different long–shafted work tools, a shavings fork and a manure fork, and investigated how variations in shaft length affected the physical workloads of the user. The methods used were generic task specification (GTS) and the Jack human simulation system (JACK). In general, adding 10 cm to the 125 cm length of the existing manure fork shaft gave the highest reduction in load on the back, especially regarding compression forces, irrespective of body height, sub–task and work technique. Simulations with the shavings fork (length 150 cm) showed that correcting user work technique considerably reduced the load on the back. Thus, it is important to consider both the shaft length of a tool and the work technique when attempting to reduce the physical work load for users.