Hand Tool Intervention for Rubber Tappers Using Modified Michie Golledge Knife

Rubber tapping is a physically demanding and skilled agricultural operation that can cause musculoskeletal disorders (MSDs). This research investigated the impact of using an ergonomically modified rubber tapping knife on the hand posture of rubber tappers.

Initially, a postural assessment was conducted using CATIA V6 modelling software followed by a non-randomized longitudinal study with 32 rubber tappers. In the second phase, the study used a custom-modified Standard Nordic Questionnaire, video recordings, and direct observations. The study compared the results of the ergonomically modified rubber tapping knife with the traditional tapping knife, evaluating hand grip strength, endurance time chip thickness, time required to complete 300 trees, and posture using the Rapid Upper Limb Assessment (RULA) tool.

Compared to pre-tapping values, the mean reduction in grip strength after tapping was significantly less with the modified rubber tapping knife than with the traditional tapping knife (2.96 kg, SD 0.85 kg vs 7.31 kg SD 2.13 kg). Similarly, the reduction in hand endurance time was less with the modified knife than with the traditional knife (1.78 seconds, SD 0.47 seconds vs 3.34 seconds, SD 0.87 seconds). The study also indicated that the modified knife did not significantly affect chip thickness. Additionally, a slight increasing in tapping time was observed with the ergonomically modified knife, which may be attributed to a learning curve phenomenon. This suggests that as rubber tappers become more accustomed to the new tool, their efficiency may improve over time.

The hand grip strength and endurance time was significantly lower with the ergonomically modified tapping knife. The study concluded that using an ergonomically modified tapping knife led to a significant improvement in hand posture among rubber tappers.