Relationship Between Hamstring Activation Rate and Heel Contact Velocity: Factors Influencing Age-Related Slip-Induced Falls

Details

• Personal Author:
  Kim SW ; Lockhart TE
• Description:
  The purpose of this research was to determine whether a decreased hamstring activation rate among the elderly is responsible for a higher horizontal heel contact velocity and increased likelihood of slip-induced falls compared to their younger counterparts. Twenty-eight subjects from two age groups (14 young and 14 old) walked across a linear walking track with embedded force platforms while wearing a fall arresting harness attached to an overhead arresting rig for safety. In order to obtain realistic unexpected slip-induced fall data, a soapy vinyl floor surface was hidden from the subjects and unexpectedly introduced. Synchronized kinematics, kinetic and electromyography (EMG) analyses during the heel contact phase of the gait cycle while walking over slippery and non-slippery floor surfaces were examined in the study. Normalized EMG data were examined in terms of hamstring activation rate and evaluated with heel contact velocity and friction demand characteristic (as measured by peak required coefficient of friction (RCOF)) on the dry vinyl floor surface. Furthermore, slip parameters (i.e. slip distances and slipping velocity) were assessed on the soapy vinyl floor surface. The results indicated that younger adults' hamstring activation rate was higher than older adults, whereas younger adults' heel contact velocity was not different from older adults. These results suggested that heel contact velocity in younger adults was sufficiently reduced before the heel contact phase of the gait cycle. This could be due to the outcome of higher hamstring activation rate in younger adults in comparison to older adults. However, lower friction demand (peak RCOF), shorter slip distances, slower peak sliding heel velocity and more falls among older adults suggested that the slip initiation characteristics were not the only factors contributing to slip-induced falls among the elderly. [Description provided by NIOSH]
• Subjects:
  Age Factors Aging Demography Musculoskeletal System Occupational Health Safety
• Keywords:
  Age-factors Age-groups Demographic-characteristics Injuries Kinetics Posture Surface-properties
• ISSN:
  0966-6362
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  23-34
• Volume:
  24
• Issue:
  1
• NIOSHTIC Number:
  nn:20031244
• Citation:
  Gait Posture 2006 Aug; 24(1):23-34
• Email:
  lockhart@vt.edu
• Federal Fiscal Year:
  2006
• Performing Organization:
  Virginia Polytechnic Institute and State University, Blacksburg
• Peer Reviewed:
  True
• Start Date:
  20010701
• Source Full Name:
  Gait and Posture
• End Date:
  20260630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bbed8bdada5624ec43db0029e44dbfdd1f72647515febf6517878bfe09a1f12c41a82502df842539816f4b7952bd4745a62e08c0140aa9bbf703d829fb18d631
• Download URL:
  https://stacks.cdc.gov/view/cdc/191548/cdc_191548_DS1.pdf
• File Type:
  [PDF - 523.17 KB ]