Isometric Cranking and Steering Strength of Agricultural Workers in Central India

Abstract

Hand cranking is the most common method of transferring power from human muscles to many stationery farm machines. On the other hand, steering torque is required for controlling tractors and other selfpropelled machines. A study was carried out to collect isometric cranking and steering strength on male as well as female agricultural workers in Madhya Pradesh. A strength measurement set-up developed at CIAE, Bhopal was used for the purpose. The mean age, stature and weight of 944 male workers were 29.8 ± 9.5 years, 1649 ± 59 mm and 51.2 ± 6.4 kg, respectively whereas the corresponding values for 757 female workers were 33.7 ± 8.2 years, 1519 ± 54 mm and 45.0 ± 7.3 kg. The mean values for isometric cranking strength in standing posture at a crank length of 265 mm by preferred hand and both hand operation were 44.1± 9.1 N.m and 50.6 ± 10.2 N.m, respectively for male workers and 31.9 ± 8.6 N.m and 37.3 ± 10.4 N.m, respectively for female workers. The mean values of steering strength in sitting posture with a steering wheel of 420 mm diameter at 700 from horizontal were 64.0± 18.8 and 40.5 ± 10.0 N.m for male and female workers, respectively. The isometric cranking and steering strengths of male workers were higher than those of female workers (p<0.001). The 5th percentile cranking strength values for preferred hand and both hands were 29.2 and 33.8 N.m, respectively for male workers and 17.7 and 20.1 N.m, respectively for female workers. The 5th percentile steering strength was 33.1 and 24.0 N.m for male and female workers respectively. For continuous operation of hand crank operated machines, the cranking effort required for operation should not exceed 30% of the maximum static cranking strength by both hands. The maximum effort requirement for steering wheel (420 mm diameter) by male workers should not exceed 19.86 N-m.