Types of Physical Workload

In a joint research project between the Federal Institute for Occupational Safety and Health (BAuA) and the German Social Accident Insurance Association (DGUV), six relevant types of physical workload have been defined on the basis of the scientific literature and expert surveys.

Whole-body Forces

For example, this is the case when processing large workpieces, when operating machines, when positioning work objects or persons, or when using tools.

The application of force is mainly stationary for this type of workload. The force is mainly applied using both hands. However, the force being transmitted via the back, the legs, and the feet is also possible in this case. The required forces are so high that this activity usually cannot be performed while sitting down. The posture may be very different.

If loads are handled within the framework of the activity, the types of physical workload may alternatively be assigned to "lifting, holding, carrying" or "pulling, pushing". If the activity includes uniform, repetitive work involving small action forces and small tools, the type of physical workload "manual work process" will rather be applicable.

Different factors determine the level of physical demands

The level of physical workload is determined by the direction, the type, and the level of the applied force. It may vary greatly when applying whole-body forces. Examples for such activities include turning and cranking, scooping, throwing, and catching. The duration of the workload is another decisive aspect. In addition, there are conditions specific for the type of workload, such as the symmetry of the application of force (using one hand or both hands) or the condition of the force transmission and application of force (gripping conditions, increased holding forces). The posture also plays an important role regarding the determination of the level of workload. Additionally, the execution conditions, for example spatial conditions, heat, cold, vibration, and clothing, as well as the distribution of the physical workload over the shift period are influencing factors as well.

Whole-body forces strain the muscles, joints, and the spinal column

The high forces exerted on the muscles used strain both the muscles and the joints of the upper and lower extremities and the spinal column. Furthermore, the contact points of the application of force, e.g. the hands and balls of the hand, are affected by the compression effect. If someone frequently performs activities involving high forces, effects on the cardiovascular system must be expected. The likelihood of overstraining is also influenced by the constitutional conditions, the physical condition, and the experiences regarding the activity performed.

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