title: The effects of insertion method and force on hand clearance envelopes for rubber hose insertion tasks.
abstract: OBJECTIVE
  The aim of this study was to determine how hand space for manual insertion of flexible hoses is affected by insertion method and force.
  
  
  BACKGROUND
  Adequate space is needed during assembly tasks in which workers join parts together with their hands. Hose installations are an example of such a task. Hand clearance envelopes for insertion tasks that involve cylindrical objects, such as a hose, are currently unavailable in the literature.
  
  
  METHODS
  Participants inserted a flexible 25-mm rubber hose onto a stationary flange using simulated methods similar to those observed in field studies of automotive assembly tasks. Markers placed on the back of the hand and wrists were used to measure postures during the insertion task.
  
  
  RESULTS
  Hand clearance envelopes for high-force insertions were significantly larger across methods by an average of 15% for both male (p < .05) and female (p < .01) participants. Rocking insertions resulted in the largest hand clearance envelopes compared with other insertion methods. Rocking and twisting the hose resulted in mean increases in the cross-sectional area of the hand clearance envelopes of 35% and 24%, respectively, compared with the straight push. Differences were significant (p < .05) for male and female participants for both bead height conditions.
  
  
  CONCLUSIONS
  Both required insertion force and method affect hand clearance envelopes during simulated insertions.
  
  
  CONCLUSIONS
  These methods can be used by engineers to determine if there is adequate clearance for the hand to grip selected objects.
authors: Department of Health Sciences, Illinois State University, Normal, Illinois 61790-5220, USA. dcgries@ilstu.edu
authors: D Christian
authors: DC
authors: Grieshaber
authors: Thomas J
authors: TJ
authors: Armstrong
authors: Don B
authors: DB
authors: Chaffin
authors: W Monroe
authors: WM
authors: Keyserling
authors: James
authors: J
authors: Ashton-Miller
mesh_terms: D000328:Adult; D005260:Female; D005542:Forearm / Q000502:physiology; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D013647:Task Performance and Analysis; D016526:Workload; D055815:Young Adult