title: A frequency-duty cycle equation for the ACGIH hand activity level.
abstract: A new equation for predicting the hand activity level (HAL) used in the American Conference for Government Industrial Hygienists threshold limit value®(TLV®) was based on exertion frequency (F) and percentage duty cycle (D). The TLV® includes a table for estimating HAL from F and D originating from data in Latko et al. (Latko WA, Armstrong TJ, Foulke JA, Herrin GD, Rabourn RA, Ulin SS, Development and evaluation of an observational method for assessing repetition in hand tasks. American Industrial Hygiene Association Journal, 58(4):278-285, 1997) and post hoc adjustments that include extrapolations outside of the data range. Multimedia video task analysis determined D for two additional jobs from Latko's study not in the original data-set, and a new nonlinear regression equation was developed to better fit the data and create a more accurate table. The equation, HAL = 6:56 ln D[F(1:31) /1+3:18 F(1:31), generally matches the TLV® HAL lookup table, and is a substantial improvement over the linear model, particularly for F>1.25 Hz and D>60% jobs. The equation more closely fits the data and applies the TLV® using a continuous function.
authors.affiliation: a Department of Industrial and Systems Engineering , University of Wisconsin-Madison , 1550 Engineering Drive, Madison , 53706-1608 WI , USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Radwin
authors.forename: David P
authors.initials: DP
authors.lastname: Azari
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Lindstrom
authors.forename: Sheryl S
authors.initials: SS
authors.lastname: Ulin
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Armstrong
authors.forename: David
authors.initials: D
authors.lastname: Rempel
mesh_terms: D001696:Biomechanical Phenomena; D006225:Hand / Q000502:physiology*; D006801:Humans; D009068:Movement; D016272:Occupational Health; D005082:Physical Exertion; D012044:Regression Analysis; D013647:Task Performance and Analysis; D020711:Threshold Limit Values; D014937:Work / Q000502:physiology*
keywords: exposure assessment; repetitive motion; work-related musculoskeletal disorders