Estimating the isometric pinch strength distribution of the population of Turkey

Abstract

Strength norms, which show cross-national variations, are important for the design of productive and safe mechanical human work and product, and clinical purposes. Through this first-ever study, the pinch strength norms of the population of Turkey are established. The main objective of this study was to estimate the maximum voluntary isometric pinch strength distribution of healthy adult population of Turkey related to gender, age, occupation, and several anthropmetric characteristics. Another objective of the study was to investigate the effects of body posture (sitting and standing) on pinch strength. For the purpose, a sample of 223 healthy volunteer participants was recruited. The study involved both laboratory and field studies. The estimated maximum voluntary isometric pinch strength types were: lateral (key) pinch, three-jaw chuck pinch and pulp pinch for both genders and tip pinch strength for males only. In addition, maximum isometric power grip strength and a number of anthropometric measurements such as weight, height, circumference of forearm, circumference of fist and forearm-hand length were measured. The results indicate that the estimated maximum mean pinch strength values for dominant hand corresponding to seated posture for males and females, respectively in kgf are: 11 and 7.7 (lateral), 9.9 and 7 (chuck), 7.8 and 5.4 (pulp), and 7 for tip pinch for males. For all three matching pinch strengths, female strengths are about 70% of male strengths. Overall, pinch strength capacity reaches its maximum at about 40-49 year age range for males and stays stable at 18-59 year age range for females. After age 60 a dramatic decrease occurs for both genders. Manual worker group was the strongest in all age groups. Dominant hand was significantly stronger than non-dominant hand. On the other hand, the tested posture did not have any significant effect on pinch strength. Pinch strength capacity of the population of Turkey is found similar to the USA population and stronger than Chinese population.