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Mining Publication: Lifting in Stooped and Kneeling Postures: Effects on Lifting Capacity, Metabolic Cost, and Electromyography of Eight Trunk Muscles

November 1988

Image of publication Lifting in Stooped and Kneeling Postures:  Effects on Lifting Capacity, Metabolic Cost, and Electromyography of Eight Trunk Muscles

Twelve healthy, experienced underground coal miners performed lifting-capacity tests in stooped and kneeling postures using a modified psychophysical procedure. Subjects adjusted weight in a lifting box to the maximum they could handle without undue fatigue in an asymmetric lifting task. Lifting periods were 20 min in duration, and the frequency was 10 lifts/min. Tests were performed under a 48-in roof that restricted the subject's posture. Psychophysical, physiological, and biomechanical dependent measures included the maximum acceptable weight of lift (mawl), heart rate (hr), rate of oxygen consumption (vo2), ventilation volume rate, respiratory exchange ratio, and integrated electromyography (EMG) of eight trunk muscles. Results indicated that mawl was significantly lower when kneeling than when stooped (p<0.05). furthermore,="" metabolic="" demands="" were="" greater="" in="" terms="" of="" hr=""><0.005) and="" vo2=""><0.05) when="" kneeling.="" left="" and="" right="" erectores="" spinae="" muscles="" exhibited="" increased="" emg="" activity="" in="" the="" kneeling="" posture=""><0.001). it="" was="" concluded="" that="" psychophysical="" lifting="" capacity="" is="" decreased,="" while="" the="" metabolic="" stress="" and="" internal="" load="" on="" the="" spine="" are="" increased,="" in="" the="" kneeling="" posture.="" results="" of="" this="" bureau="" of="" mines="" study="" indicate="" that="" it="" may="" be="" advisable="" to="" reduce="" the="" weight="" of="" materials="" that="" are="" handled="" repetitively="" in="" the="" kneeling="">

Authors: S Gallagher, WS Marras, TG Bobick

Peer Reviewed Journal ArticleNovember - 1988

  • Adobe Acrobat - Portable Document Format (.PDF)

    0.48 MB

NIOSHTIC2 Number: 10006601

Int J Ind Ergon 1988 Nov; 3(1):65-76

 
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