Preliminary Assessment of Biomechanical Load Characteristics During Common Agricultural Tasks in Benue State Smallholder Farmers

Musculoskeletal disorders from agricultural labour are a significant occupational health burden among smallholder farmers in Benue State, and biomechanical assessment of postural and loading characteristics during common farming tasks informs the design of ergonomic interventions and assistive tools. This study presents a preliminary biomechanical assessment of postural load and joint moment characteristics during three common agricultural tasks, namely manual ploughing, yam harvesting, and sorghum threshing, performed by smallholder farmers in Gwer East LGA, Benue State. Twenty-two male farmers aged between twenty-two and forty-eight years participated in task recording. Upper body and trunk postures during task performance were assessed using a modified RULA (Rapid Upper Limb Assessment) observational method. Supplementary wrist and lumbar acceleration data were captured using commercially available accelerometer loggers worn during full task cycles. Peak angular velocities and acceleration magnitudes at the lumbar region were extracted from accelerometer data. RULA assessment classified manual ploughing as requiring immediate investigation and corrective action, with a maximum RULA score of seven, due to extreme trunk and shoulder flexion. Yam harvesting scored six, while sorghum threshing scored five. Accelerometer data confirmed repeated high-magnitude lumbar acceleration events during ploughing that exceeded published limits associated with elevated low back injury risk. Shoulder and wrist fatigue ratings were highest during sorghum threshing. The study provides preliminary biomechanical data supporting the design of long-handled implement modifications and postural break protocols for Benue State agricultural extension health programmes. Keywords: biomechanical assessment, agricultural tasks, musculoskeletal disorders, RULA, Benue State.