The relationship of isometric strength to peak dynamic hand forces during submaximal weight lifting

Abstract

Reports have indicated that approximately one third of the US workforce is presently required to exert significant strength as part of their jobs. In addressing the prevention of these types of injuries, the assessment of muscular strength can provide a method of predicting whether a person is capable of performing the job without incurring injury. Currently, isometric strength assessments are often used to assist in predicting the capability to safely perform a lifting task. However, given the dynamic nature of work activities, isometric values may be limited, particularly if the load is well below a person's strength capability. Thus, it is of interest to evaluate the relationship between isometric strength values and peak dynamic hand forces under varied submaximal loading. It is shown in this study that the peak hand forces, exhibited while dynamically lifting different submaximal loads, are not highly correlated with a person's isometric lifting strength in similar postures. It is also shown that for very light load lifting, the peak accelerations approached 2.5 g's, further supporting the need to limit such lifting from floor level by using ergonomic interventions.