Maximum handgrip strength as a function of type of work and hand-forearm dimensions

BACKGROUND: Handgrip strength is a measurement of upper extremity functionality and an indicator of overall physical ability. OBJECTIVES: The objective of this study was to compare maximum handgrip strength (MGS) between manual workers and office employees and to investigate if the expected difference is related to the anthropometric dimensions of the workers' hands and forearms. METHODS: This was a cross-sectional study with a sample of 1740 male workers (905 light manual workers; and 835 office employees), aged 20-64 years. Maximum voluntary contractions were obtained using a JAMAR dynamometer according to the methodology proposed by the American Society of Hand Therapy (ASHT). The highest value obtained from three trials was considered as the MGS for each side. Six anthropometric dimensions (i. e ., hand length, palm length, forearm length, hand breadth, wrist circumference and forearm circumference) were measured by digital caliper and tape measure. RESULTS: Maximum handgrip strength of light manual workers (52.7 +/- 8.5 kg) was significantly higher than that of office employees (47.3 +/- 8.4 kg) (p < 0.001). Maximum handgrip strength was positively correlated with Hand breadth (r= 0.781 for light manual workers and r = 0.766 for office employees; p < 0.001) and Forearm circumference (r = 0.741 for light manual workers and r= 0.752 for office employees; p < 0.001); the only dimensions which were significantly different between the two studied job groups. CONCLUSIONS: The results of this study revealed that light manual workers are approximately 12.4% stronger than office employees in terms of maximum handgrip force. It is therefore imperative to consider the observed differences in clinical, workstations, and hand tool designs in order to increase efficiency and comfort at work.