Print Email Facebook Twitter Trunk muscle activation and low back loading in lifting in the absence of load knowledge Title Trunk muscle activation and low back loading in lifting in the absence of load knowledge Author de Looze, M.P. Steenhuizen, S. Boeken-Kruger, M.C. Baten, C.T.M. Kingma, I. van Dieën, J.H. Publication year 2000 Abstract People who know the actual mass of an object to be lifted normally prepare themselves before attempting a lift to control the movement and to minimize low back loading. In this study, the trunk muscular reactions and low back torque were investigated in the situation in which the individual did not know the actual mass but only had some idea of the range within which the mass lay. Nine males lifted boxes weighing 6.5 or 16.5 kg under the condition in which they knew the actual mass before attempting a lift (the 'known' condition) and the condition in which they only had the information that the mass would be within the range of 6.5 - 16.5 kg (the 'unknown' condition). The ground reaction forces and body movements were measured in the trials and, from these, the L5/S1 torques were calculated. The activation of back and abdominal muscles was also measured. For the 6.5 kg weight, a higher (16%) back muscle activation in grasping the box and a higher (10%) peak L5/S1 torque in actual lifting were observed in the 'unknown' compared with the 'known' weight condition. For the 16.5 kg weight, the back muscle activation was lower (10%) during grasping, and higher (10%) during lifting in the 'unknown' compared with the 'known' weight condition. Knowledge of the load had no effect on the activation of the abdominal muscles. It was concluded that in the so-called 'unknown' conditions, the risks of low back injury were increased in comparison with the conditions where the actual weight was known in advance. Subject WorkplaceLichaamshoudingLichaamsbewegingTillenRugklachtenHerniaLoad knowledgeMovement controlMuscle activationSpinal loadAbdominal wall musculatureBack muscleBody movementControlled studyHumanHuman experimentLifting effortLow back painLumbosacral spineMovement (physiology)Normal humanWeight liftingAbdominal MusclesAdultBackElectromyographyHumansLiftingMaleMultivariate AnalysisMuscle ContractionMuscle, SkeletalPsychomotor PerformanceTorqueWeight-Bearing To reference this document use: http://resolver.tudelft.nl/uuid:4a81a4f3-3c4c-4f7a-bbf9-cfaa9e0e3234 TNO identifier 276649 Source Ergonomics, 43 (3), 333-344 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.