Stoop or Squat: A Biomechanical and Metabolic Evaluation

Publisher Website
Google Scholar
Abstract
For the past 40 years it has been widely advocated that all lifting be carried out with a “squat lifting posture” (bend at the knees, back erect). The presumed basis for this has been to reduce the compressive force on the low back. Detailed biomechanical evaluations show that the more common “stooped lifting posture” (bend at the waist) may in fact be superior to the recommended squat method on this basis, even when the load can be placed close to the body. The compressive force on the lumbosacral disc is estimated to be equal or slightly lower for loads greater than 5 kg when the load is lifted using the stooped lift posture. This should not be viewed as sufficient evidence to reject conven- tional wisdom. The compressive force with the stooped-lift posture may in turn lead to a non-uniform distribution of pressure over the disc, thus enabling a smaller compressive force to produce rupture. Thus, there is no clear biomechanical rationale for deciding between the two postures. Using metabolic energy expenditure rate, on the other hand, as a basis for comparison suggests lifting with a stooped lift posture is preferred. It is further concluded that lifting heavy loads at slower paces is physically less taxing (in a metabolic sense) to the worker than lifting light loads at faster paces. The resulting trade-offs between the two criteria are discussed.

This publication has 12 references indexed in Scilit: