Citation

Nag PK, Pradhan CK. Int. J. Ind. Ergonomics 1992; 10(4): 341-350.

Copyright

(Copyright © 1992, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The hoeing operation is extensively required in farm tasks, such as seed-bed preparations, cutting root crops, etc. In seven male farmers (age: 27.4 +/- 5.9 years), using two types of hoes (A and B), the physiological and biomechanical strains were evaluated, and hoeing speeds in low lift (LL) and high lift (HL) work were optimized. The heart rates (161-176 beats/min) and VO2 demands (71-89% VO2max) indicated extremely heavy work loads. Hoe A (blade-handle angle: 65[deg]) was less strenuous in LL, while Hoe B (blade-handle angle: 87[deg]) was better in HL work. During the hoeing sequence, the torque and compressive forces at the L5-S1 disc increased with the trunk inclination, up to about 65[deg]; beyond 55[deg] inclination, the torque at the L5-S1 disc exceeded the upper limit (135 Nm) allowed for a day's work. The work output was optimized equating at 50% VO2max, i.e, stroke rate: 53 and 21 strokes/min; weight of soil dug: 123 and 54 kg/min, and area of soil dug: 1.34 and 0.33 sq.m./min in LL and HL work respectively. In general, farmers are suggested to adopt the LL mode of hoeing; with a 10 min work to 7 min rest ratio, the 8 h work output was derived as 400 to 450 sq.m. A hoe, weighing about 2 kg, having blade-handle angle 65 to 70[deg], blade length 25 to 30 cm, blade width 22 to 24 cm, handle length 70 to 75 cm, and the handle diameter 3 to 4 cm may be suitable for different modes of hoeing.