Biomechanical Analysis of Shoveling Tasks

Aim  Biomechanical analysis of the external and internal musculoskeletal loads during shoveling tasks.  Methods  The three-dimensional motions of the human body and the shovel were captured by means of a VICON system (8 cameras). For measuring the hand forces a standard shovel was instrumented with two six-axis force transducers. The support forces of the handle on the thigh were measured by a pressure sensitive mat attached at the thigh. The compression forces at the lumbar spine (L5/S1) were calculated by means of the biomechanical model ‘The Dortmunder’ [1]. Five skilled and healthy workers from different areas of the construction sector were analyzed practicing their favorable shoveling technique under 12 typical material/task combinations.   Results  On average, one shoveling operation associated with a bulk load of 7.0 kg (SD 1.3 kg) lasted 2.1 s (SD 0.5 s) from loading until unloading. The maximum force of the hand close to the blade reached, on average, approx. 260 N (SD 48 N), and the hand at the far end reached approx. 210 N (SD 56 N). An average maximum bearing force of the handle on the thigh of 200 N (SD 85 N) was recorded. The peak compression force at L5/S1 was estimated at approx. 3.5 kN (SD 0.4 kN).  Conclusions  The results demonstrated that shoveling is a highly individual skill associated with extensive spatial motions and asymmetric loadings of the musculoskeletal system. The handle support on the thigh during insertion and lifting of the shovel is a major factor for reducing the lumbar load-ing. Nevertheless, shoveling must be considered a physically demanding task which requires qualified education and highly exposed workers should receive routinely medical check-ups.   References  1 Jäger M, et al.: SAE Digital Human Modeling Conference, Arlington, Virginia, U.S.A., 2001.