J. K. SinghCHANCHALA PRIYA2017-05-022017-05-022015http://krishikosh.egranth.ac.in/handle/1/5810010409T-9227A large number of agricultural equipment needs manual power for their operation. Push and pull action are extensively used to operate most of the manual tools involved in agricultural activities. The push pull strength varies significantly with respect to work load, duration of work, physiological and postural parameters of operator. Repetitive and continuous operation of these equipment results in postural stress, which lead to musculoskeletal disorders in operators if used for longer period of time. Hence the ergonomic assessment of hand tools is needed for drudgery reduction and increase efficiency. This study was conducted to find out the best forearm posture in ideal combination of muscles to optimize push/pull strength. An experimental set up was fabricated to generate the push/pull task. Experiments were conducted for seven forearm positions viz. neutral, pronation, dorsiflexion, palmer flexion, radial deviation, ulnar deviation and supination. Ergonomic evaluation in terms of heart rate, oxygen consumption, energy expenditure, body part discomfort (BPDS) and overall discomfort score(ODS) were assessed for different forearm position at different loads. To conduct the experiment five subjects were selected from available work force in ergonomic laboratory at Division of Agricultural Engineering ICARIARI New Delhi. The subjects were in the age group of 30-45 years. Maximum aerobic capacity of subjects were computed by extrapolation from calibration charts.. The relationships between heart rate (beats per minute) and oxygen consumption (litre per minute) were found to be linear for all the subjects. The maximum aerobic capacity (VO2 max) of the selected subjects varied from 2.05 to 2.35 l min-1 . Total 315 experiments were conducted on seven modes of forearm posture and three load output conditions namely 45, 67 and 90 N. The working heart rate (beats min-1 ), oxygen consumption (l min-1 ), energy expenditure (kJ min-1 ), ∆HR (beats min-1 ) ,% VO2 Max, BPDS and ODS were highest for radial deviation and lowest for neutral deviation of forearm postion. Higher load output condition under all the seven ii forearm position force application the ∆HR (beats min-1 ) values exceeded the limit for continuous performance level (40 beats min-1 ).The observations reflect that these can be short duration operations and must be continued with sufficient rest allowance. The percent VO2 max value were much higher than the acceptable work load for all modes of operations with higher load output conditions. This again reveals that all mode of operation could not be performed continuously without frequent rest. BPDS and ODS value were also highest for radial deviation for forearm position signifying that this mode of operation was most uncomfortable and strenuous whereas neutral position was quite opposite which is most comfortable and least strenuous. Based on the result in terms of maximum push pull strength and ergonomic parameters, it was found that neutral forearm posture is the best mode of force application. However there was similar push pull strength in the range of handles orientation from 00 to 350 from the neutral position.ennullThesis