Relation Between Long Term Adoption of Awkward Posture and Work Related Musculo Skeletal Disorders in Pickaxe and Spade Users in China clay mine

Abstract

Work-related musculoskeletal disorders (WRMSDs) and discomfort rating at different body segments have multifactorial etiology. Literature review evident that gradual onset of WRMSDs and discomfort rating are linked not only with adoption of awkward postures but to duration also.The present study was aimed to correlate the prevalence of lower back disorder, waist disorder and discomfort rating of pickaxe and spade users in china clay mine with postural stress during performing mine tasks.The study was carried out on 180 male china clay mine workers (25 yrs -35 yrs age) of different china clay mines of Birbhum district of West Bengal (India). The workers were performing different types of mine tasks. Lower back disorder, waist disorder and discomfort rating were evaluated by questionnaire method. The postural stresses were studied by direct observation method as well as Ovako Working posture Analysis System (OWAS) employing video-photography.The china clay mine workers were affected in different body segments during work. High prevalence of lower back disorder (>75%), waist disorder (>82%) and severe (6.6) to very severe (>7.2) discomfort rating was predominant in spade and pickaxe users. It was also observed that the frequency of occurrence of disorders in the workers doing pickaxe and spade operation was significantly higher than workers performing all mine tasks (P<0.001). Results of postural analysis revealed that china clay mine workers had adopted forward bending and twisting postures for prolonged duration. Analysis of the bent posture shown that the workers performing pickaxe and spade operation had higher (<100°) and moderate (>100° and <120°) degree of bending for a longer duration of time (37.30% and 53.22 % of total duration of work respectively). The rate of major posture change was also higher during those operations. Postural analysis by OWAS method indicated that posture adopted was distinctly harmful and the risk of MSD was significant (action category 3) in the above mentioned tasks. Occurrence of lower back disorder, waist disorder and high discomfort rating among the pickaxe and spade users in china clay mine might be due to adopting long term awkward posture including bend and twist posture along with frequent posture changes.