Quantifying the Recovery Response and Role of Hand Strength During Ladder Falls

Details

• Personal Author:
  Rahman M
• Description:
  Falls from ladders represent one of the leading causes of occupational injuries and fatalities. The primary factors contributing to falls from ladders are missteps and foot slips. A critical need exists to identify risk factors and characterize the response to ladder slips and missteps. Over the past three years, we have generated new knowledge on the biomechanical response to ladder perturbations and risk factors that influence the outcomes of ladder falls. These studies have quantified the response to a ladder missteps and slips (Aim 1) and the role of hand strength in recovery (Aim 2). In addition to these aims, we have also identified several risk factors for slipping and falling during ladder climbing. Aim 1: Slipping and misstep perturbations were analyzed to characterize the response of the contact points (two hands and two feet) after a slip or a simulated misstep. Ten out of fifteen subjects who experienced a slip had only one point of contact with the ladder after the foot slipped off. The events after a ladder slip were sequenced. The hand in motion was the first to re-contact the ladder after the slip followed by the foot contralateral to the slipping foot. The slipping foot was the last to reestablish contact with the ladder. During our simulated misstep experiments, we found four different hand responses and three different foot responses to the perturbation. The hand responses were characterized based on the placement of the hand after the perturbation and included advancing the hands two rungs (e.g., hand movements were the same as unperturbed climbing), advancing the hands one rung (interrupting hand movements to grasp an intermediate rung), re-grasping the rung that the hand was originally grasping, and maintaining both hands on the rung throughout the entire perturbation. The three foot responses were characterized by the number of feet that were placed on the rung after the simulated misstep. Aim 2: We quantified the effects of glove use and arm posture on maximum pull strength and quantified the relationship between pull strength on recovery during simulated missteps. Increased hand-rung friction and a more extended arm posture were associated with greater pull strength. Certain measurements of hand strength were associated with improved recovery during ascent but not during descent. Differences in pull strength across the three glove conditions did not lead to changes in the recovery. Strength was not found to be as strong of a predictor of recovery as other variables such as hand and foot placement. Identified Risk Factors for Ladder Climbing: Several risk factors were identified that influenced slip risk and recovery. Restricted foot placement; longer double stance time; more variable foot and body angles; grasping the rungs versus the rails; and being under the age of 25 years were associated with higher slipping risk. Female subjects had more severe falls than male subjects. Less severe falls were associated with ascending the ladder (compared with descending), reestablishing the feet on the rungs and placing the hand on higher rungs. [Description provided by NIOSH]
• Subjects:
  Accidental Falls Accidents Age Factors Biomechanical Phenomena Occupational Health Personal Protective Equipment Risk Assessment Risk Factors Safety Sex Characteristics
• Keywords:
  Age Factors Biomechanical Engineering Biomechanics Falls Gender Factors Gloves Ladders Risk Factors Safety Practices Slips
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  OSHA Region 5 ; Wisconsin
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-43
• NIOSHTIC Number:
  nn:20053706
• NTIS Accession Number:
  PB2019-100321
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-010038, 2015 Nov; :1-43
• Contact Point Address:
  Mohammad Rahman, Ph.D., University of Wisconsin-Milwaukee, College of Engineering & Applied Science, EMS Building Room 1255, 3200 N. Cramer Street, Milwaukee, WI, 53211
• Email:
  rahmanmh@uwm.edu
• Federal Fiscal Year:
  2016
• Performing Organization:
  University of Wisconsin at Milwaukee
• Peer Reviewed:
  False
• Start Date:
  20120901
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20150831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:2a62fc449526eda136463bad118d292cba01eeff0c56130ee8d0cdd664a19566dd96e408069369355eeaccb06fbe0bbaf39527b52c5840c8ae1279ce8205d481
• Download URL:
  https://stacks.cdc.gov/view/cdc/218777/cdc_218777_DS1.pdf
• File Type:
  [PDF - 1.34 MB ]