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Abstract
The ACGIH Hand Activity Level (HAL) Threshold Limit Value (TLV) is a risk assessment tool designed to protect workers, who perform repetitive hand exertions for 4 or more hours per day, from distal upper extremity disorders. Recent large, longitudinal studies, provide strong evidence that repetitive forceful hand exertions increase risk for occupational wrist tendinosis and carpal tunnel syndrome.1,2,3 In the Harris-Adamson study,3 forceful hand exertions (e.g., >9N pinch or >45N power grip force) and the%time performing forceful hand work increased risk. Based on these and psychophysics studies,4 hand exertions should be considered in risk assessment models if they are above 10% of posture specific strength. In addition, in these large studies, the prior HAL TLV action limit (0.56) was not sufficiently protective5 and, therefore, has been revised. The name of this TLV was changed to Hand Activity (HA) TLV. Other changes to the TLV will also be presented.
References
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