A back and lift test

In addition to the standard medical examination, a back and lift test has been introduced in the hiring of new employees. 100 men have been tested to date. Only people with no history of back trouble were tested. Body height and weight were measured and the isometric capacity of the back extensors and the strength of abdominal musculature were measured with a Darcus dynamometer. A series of lifts with gradually increasing weight were performed in order to find the subject's 'acceptable weight'. The correlation coefficients for these different test variables was consistently poor, and thus it is not possible to predict a person's true lifting capacity from knowledge of muscle strength, height and body weight. The subjects stood upon a force plate during the lifts, which recorded the vertical and horizontal forces, and the force of inertia exerted by the subject during the lift could be calculated. The activity in the back extensors, rectus abdominis and external oblique muscle was recorded. The flexibility of the lumbar spine was calculated.