A biomechanical investigation of forces applied to the lift truck steering wheel: effects of posture,gender and hand contact on cumulative low back loading

Hand contact forces on a typical lift truck steering wheel were quantified in a laboratory to determine their effects on low back loading. A single muscle equivalent link segment model (3D Match) was used to estimate cumulative loading exposure variables at the L4/L5 intervertebral disc with and without hand contact forces. Hand contact forces significantly decreased cumulative L4/L5 compression in forward bending (FB) for males by 32% and females by 14%. Cumulative L4/L5 compression in males (37,023?±?2183?Ns) was not different from that in females (38,413?±?2224?Ns). When excluding hand contact forces, males had significantly greater cumulative L4/L5 compression (55,165?±?1593?Ns) in FB compared to females (43,255?±?1753?Ns). Hand contact forces on mobile equipment controls might result in decreased cumulative L4/L5 compression, especially in awkward trunk postures. Females may be further predisposed to injury resulting from exposure to cumulative load.