Ergonomic assessment of drivers in MF285 and MF399 tractors during clutching using algometer

Tractor as one of the most widely used agricultural machinery should be considered from different aspects.The frequent application of clutch and brake pedals and also the steering wheel within farms,along with the unfavorable working conditions,cause negative effects on the occupational health of the tractor drivers.Thus,in this research,the imposed forces on three engaged muscles including:Gastrocnemius,Trapezius and Quadrate’s lumborum of the tractor drivers during clutching have been studied.In this regard,algometer device was used to determine the applied forces on selective muscles of drivers during clutching of MF285 and MF399 tractors.The experiments were performed employing sample of 30 drivers and were conducted on two Iranian frequently used tractors including:MF285 and MF399 models.The results showed that the clutching forces for MF285 and MF399 tractors were 340 N and 290 N,respectively.The knee angle of the drivers of the two tractors was statistically different at the one percent level of significance.The reduction of pain threshold after 30 and 60 s clutching and also 60 s rest after clutching in MF285 tractor,for all three muscles,were more than those of MF399 tractor.The impact of clutching on the average decreases of pain threshold,for all drivers and all clutching periods,during and after clutching,in the Quadratus lumborum muscle was more than the other two muscles,in both tractors.In order to reduce the clutching force for MF285 tractor some modifications is suggested.In this regard the force transfer joint between the pedal and the clutch release linkage may be replaced with one made of cast iron.

Lumbar interspinous pressure pain threshold values for healthy young men and women and the effect of prolonged fully flexed lumbar sitting posture:An observational study

BACKGROUND Low back pain(LBP)is a common condition with large burden worldwide.Exposure to prolonged sitting with a flexed lumbar posture has been suggested in the literature to be a potential risk factor for self-reported LBP.No study has previously investigated whether exposure to prolonged flexed sitting posture provokes discomfort/pain and decreased interspinous pressure pain thresholds for healthy young men and women without back pain,despite this being a suggested risk factor for LBP.AIM To investigate whether sitting in a prolonged flexed lumbar posture provokes discomfort and lowers interspinous pressure pain thresholds in the lumbar spine for healthy young men and women without previous LBP.METHODS This is a an observational before and after study of 26 participants(13 men,13 women)between 20-35 years old.Algometry was used to examine the pain threshold for pressure applied between spinous processes of the lumbar spine L1-L5.Pressure algometer measures were performed in prone before and after participants were instructed to sit in a fully flexed posture for a maximum of 15 min or until discomfort was experienced in the low back(Borg CR10=7/10).Wilcoxon signed-rank test was used for analyze values from the before and after test conditions.Mann-Whitney U test was used to investigate potential gender difference.RESULTS Fully flexed lumbar spine sitting posture up to 15 min provoked temporary discomfort but the proportion of participants experiencing discomfort 7/10 in the low back was 62%.For all pain pressure threshold locations tested,there was a significant difference for the study population with moderate-large decreased(r=-0.56)pressure pain threshold after exposure to prolonged flexed sitting posture(P<0.01).Comparisons between gender did not show any significant difference.CONCLUSION The result showed that exposure to fully flexed lumbar sitting posture for up to 15 min produced temporary discomfort in the low back in young healthy adults with no previous history of LBP and significantly reduced lumbar interspinous pressure pain thresholds.No gender-based differences were observed.