Estimation of static hand torque strength capacity of adult male population of Turkey

Abstract

Human muscle strength is still the main source of power for considerable number of industrial jobs and in many daily life activities. Strength norms are important for safe and efficient design of work, equipment and product. Most of these norms are not universal and are likely to show cross-national variations. The objective of this study are to establish the isometric (static) hand torque strength norms of healthy male population of Turkey, and investigate the effects of handle type, posture, age-group, job-group, BMI-group and several anthropometric variables on hand torque strength. A sample of 257 healthy adult male volunteers aged between 18 and 69 with family roots from all seven regions of Turkey participated in the study. Maximum voluntary hand torque strengths of dominant hand were measured both in sitting and standing postures with four different handles (ellipsoid, circular, key and cylindrical) by using a Torque Tester. The mean and standard deviation of maximum hand torque strength values (in Nm) are 6.97±1.85 for cylindrical handle, 4.97±1.21 for circular handle, 4.19±1.1 for ellipsoid handle and 2.01±0.42 for key handle. The hand torque strength peaked in (40-49) age group for both manual and non-manual job-groups in three handles (ellipsoid, circular and key). For cylindrical handle, hand torque strength peaked in (18-29) age group for both manual and non-manual job-groups. Manual workers, on average, were found stronger than non-manual workers. Sligthly greater strength values were recorded in standing posture. Grip strength and some of the anthropometric variables were significantly correlated with torque strength. A comparison study was also made with torque strength data of some other populations. Through this study, static hand torque strength norms of adult male population of Turkey are established between the ages of 18 and 69 years. These norms can be a 'reference' in the design for torque strength for male population of Turkey. In addition, the norms can contribute to the development of the strength database for the population of the world.