Evaluation of a knee-kicker bumper design for reducing knee morbidity among carpet layers

Carpet layers have a high prevalence of occupational knee morbidity. One of the main causes is that they need to frequently ‘kick’ the bumper on the rear end of the knee kicker with one knee when laying a carpet. Considering the bumper’s marked effects on kicking force transmission and safety, this study aims to improve the design of the knee-kicker bumper by reducing the risk factors. An improved pendulum-type impact-testing platform was designed as an evaluative apparatus, with the impulse and the coefficient of restitution serving as evaluative criteria. The newly developed bumper has improved firmness from drilled blind holes and an increase in effective forward force of 15%–138%, which implies lower operational demands and a lighter knee burden (i.e., less kicking energy results in the same work efficiency), and a softer contact surface that enhances operating comfort. The newly designed kicker was positively reviewed by subjects.

► Serious knee injuries frequently result with the use of a knee-kicker.
► Working carpet layers frequent use of the knee as a hammer.
► An improved pendulum-type impact tester was designed as an evaluative apparatus.
► The newly developed bumper has improved firmness from drilled. blind holes.
► An increase in effective forward force of 15%–138%, implying a lighter knee burden.