Ergonomic assessment of traditional hand tools can be done either by heart rate or oxygen consumption measurement or subjective methods like RULA, REBA, discomfort scale etc. You can also see my some of papers. After that if you have any confusion, please let me inform.
Singh, S P. 2015. Physiological Workload of Women Agricultural Labourers in Selected Activities in Maize Cultivation. Journal of The Institution of Engineers (India), Series A: 96(1), 21-25
Singh, S P. 2013. Ergonomical evaluation of hand operated maize dehusker-sheller with farm women. Agricultural Engineering International: CIGR Journal, 15(2), 194-202.
No problem - You may also wish to look at the ORCA, the Washington State Ergonomic and MSD Risk Assessment tool or the Liberty Mutual Manual Material Handling Tables. I will be uploading more publications shortly. Good luck!