#### Event Title

Quantifying Hand Activity Level (HAL) from Frequency and Duty Cycle: a Comparison of Using All Exertions versus Forceful Exertions

#### Mentor 1

Dr. Jay Kapellusch

#### Location

Union Wisconsin Room

#### Start Date

29-4-2016 1:30 PM

#### End Date

29-4-2016 3:30 PM

#### Description

HAL uses frequency and duty cycle of hand exertions to measure repetition and is used to predict injuries of the hand in the workplace. HAL is commonly quantified using verbal anchor scale or tabular lookup. Recently, Radwin et al. developed an equation to quantify HAL using frequency and duty cycle of exertions^{1}. It is common for varying levels of force to be used when performing exertions and there is little guidance for which exertions should be included and which should be ignored when calculating HAL. The objective of this study is to see if there are marked differences in calculated HAL ratings when using total versus forceful exertions using data from a prospective study. Frequency of exertion and duty cycle ratings from 10,244 tasks performed by 1,784 predominantly manufacturing workers were evaluated. Data were obtained for left and right hands separately, and force (Borg CR-10 rating) frequency and duty cycle of exertion were provided for all exertions. HAL ratings were computed using forceful exertions, defined as exertions having a Borg rating greater than or equal to 2, and total exertions, defined as all exertions regardless of force level. HAL ratings were highly correlated with frequency for both forceful exertions and total exertions (R^{2} = 0.93, and R^{2} = 0.88, respectively). HAL ratings were more poorly correlated with duty cycle (R^{2} = 0.68, and R^{2} = 0.22 for forceful and total exertions, respectively). Forceful exertion HAL ratings and total exertions HAL ratings were poorly correlated (R^{2} <= 0.47). Radwin et al. equation for computing HAL ratings appears to be biased towards frequency. HAL ratings for a given task are markedly different depending on whether forceful or total exertions are used in the calculations. Further testing is needed to determine whether HAL for forceful exertions or HAL for total exertions should be used to determine risk of distal upper limb musculoskeletal disorders.

Quantifying Hand Activity Level (HAL) from Frequency and Duty Cycle: a Comparison of Using All Exertions versus Forceful Exertions

Union Wisconsin Room

HAL uses frequency and duty cycle of hand exertions to measure repetition and is used to predict injuries of the hand in the workplace. HAL is commonly quantified using verbal anchor scale or tabular lookup. Recently, Radwin et al. developed an equation to quantify HAL using frequency and duty cycle of exertions^{1}. It is common for varying levels of force to be used when performing exertions and there is little guidance for which exertions should be included and which should be ignored when calculating HAL. The objective of this study is to see if there are marked differences in calculated HAL ratings when using total versus forceful exertions using data from a prospective study. Frequency of exertion and duty cycle ratings from 10,244 tasks performed by 1,784 predominantly manufacturing workers were evaluated. Data were obtained for left and right hands separately, and force (Borg CR-10 rating) frequency and duty cycle of exertion were provided for all exertions. HAL ratings were computed using forceful exertions, defined as exertions having a Borg rating greater than or equal to 2, and total exertions, defined as all exertions regardless of force level. HAL ratings were highly correlated with frequency for both forceful exertions and total exertions (R^{2} = 0.93, and R^{2} = 0.88, respectively). HAL ratings were more poorly correlated with duty cycle (R^{2} = 0.68, and R^{2} = 0.22 for forceful and total exertions, respectively). Forceful exertion HAL ratings and total exertions HAL ratings were poorly correlated (R^{2} <= 0.47). Radwin et al. equation for computing HAL ratings appears to be biased towards frequency. HAL ratings for a given task are markedly different depending on whether forceful or total exertions are used in the calculations. Further testing is needed to determine whether HAL for forceful exertions or HAL for total exertions should be used to determine risk of distal upper limb musculoskeletal disorders.