Effects of handle vibration on handgrip strength of operators of a diesel powered single axle tractor

Abstract

Hand–arm vibration (HAV) is a major occupational hazard in agriculture, particularly in low- and middle-income countries where single-axle tractors are widely used without effective vibration control. However, few studies have combined real-field vibration measurements with physiological performance indicators. This study assessed the effects of handle-transmitted vibration on handgrip strength and fatigue resistance under actual working conditions. Seven experienced operators performed tillage using a 15-horsepower diesel-powered single-axle tractor. Handgrip strength of both dominant and non-dominant hands was measured before and after 30 min of operation using a calibrated dynamometer. Vibration exposure was recorded using a tri-axial accelerometer mounted on the tractor handle. Handgrip strength significantly decreased after vibration exposure. Dominant hand strength declined from 33.6 ± 2.7 kg to 26.3 ± 3.3 kg (21.7%), while non-dominant hand strength decreased from 28.7 ± 2.9 kg to 23.1 ± 1.9 kg (19.5%). Fatigue resistance decreased significantly, indicating reduced muscular endurance. Measured vibration levels exceeded recommended safety thresholds, highlighting substantial occupational risk. Prolonged exposure to handle-transmitted vibration adversely affects neuromuscular performance and operator efficiency. These findings underscore the need for ergonomic interventions, vibration reduction technologies, and improved machinery design to enhance safety in small-scale agricultural operations.