Investigation of hand muscle fatigue and its influential factors in manual tasks

Effect of work experience and upper-limb muscle activity on grip strength of manual workers

Objectives. The current study correlated grip strength (GS) measurements with upper-limb muscle activity (UMA) for three different experience levels of manual workers (beginner, intermediate and advanced). Methods. A total of 182 male and female manual workers were chosen, and GS was assessed in some contexts using a digital handgrip dynamometer. Results. The GS values change significantly depending on the amount of experience of the workers. The difference in GS for different UMA demonstrates that continuous exposure to hand tools in different conditions of the hands (twisting, bending, etc.) significantly impacts manual arm strength. Conclusions. These findings suggest that repetitive use of hand tools in various manual operations (cutting, digging, pruning, spading, etc.) causes GS to vary significantly. In addition, beginner experience-level individuals exhibited much lower GS values in the dominant hand, whereas advanced experience-level workers had the greatest strength. Thus, for generating higher forces, professionals (advanced and intermediate levels) choose to execute safer activity (i.e., more neutral positions) than beginners.