Workload of window cleaners using ladders differing in rung separation.

The objective of the present study was to compare energetic workload, perceived exertion, perceived discomfort, safety, and mechanical load at lower limb joints among window cleaners during usage of extension ladders with 30 and 35 cm rung separation. Eleven healthy male professional window cleaners of short and tall stature participated in this study. No significant differences between 30 and 35 cm rung separation were observed for the energetic workload. Results concerning the perceived exertion, discomfort, and safety indicate that 35 cm rung separation is preferred. Based on the mechanical load at the hip, knee, and ankle during ascending and descending the ladder, 30 cm rung separation is preferable to 35 cm rung separation. It is advised to climb ladders with the knees inside the side rails of the ladder, but this seems only possible with 35 cm rung separation. Findings of the presents study suggest that overall, a 35 cm rung separation is marginally favourable while using extension ladders.