PMID- 16112575
OWN - NLM
STAT- MEDLINE
DCOM- 20070222
LR  - 20181113
IS  - 0966-6362 (Print)
IS  - 1879-2219 (Electronic)
IS  - 0966-6362 (Linking)
VI  - 24
IP  - 1
DP  - 2006 Aug
TI  - Relationship between hamstring activation rate and heel contact velocity: factors 
      influencing age-related slip-induced falls.
PG  - 23-34
AB  - 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.
FAU - Lockhart, Thurmon E
AU  - Lockhart TE
AD  - Industrial and Systems Engineering, Virginia Polytechnic Institute and State 
      University, Blacksburg, VA, USA. lockhart@vt.edu
FAU - Kim, Sukwon
AU  - Kim S
LA  - eng
GR  - L30 AG022963-02A1/AG/NIA NIH HHS/United States
GR  - K01 OH007450/OH/NIOSH CDC HHS/United States
GR  - UR6/CCU617968/PHS HHS/United States
GR  - K01- OH07450/OH/NIOSH CDC HHS/United States
GR  - L30 AG022963/AG/NIA NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
DEP - 20050819
PL  - England
TA  - Gait Posture
JT  - Gait & posture
JID - 9416830
SB  - IM
MH  - *Accidental Falls
MH  - Adult
MH  - Age Factors
MH  - Aged
MH  - Analysis of Variance
MH  - Biomechanical Phenomena
MH  - Female
MH  - Heel/*physiology
MH  - Humans
MH  - Male
MH  - Muscle, Skeletal/*physiology
MH  - Thigh
MH  - Time Factors
PMC - PMC2895264
MID - NIHMS212268
EDAT- 2005/08/23 09:00
MHDA- 2007/02/23 09:00
PMCR- 2010/07/01
CRDT- 2005/08/23 09:00
PHST- 2004/04/01 00:00 [received]
PHST- 2004/10/13 00:00 [revised]
PHST- 2005/06/12 00:00 [accepted]
PHST- 2005/08/23 09:00 [pubmed]
PHST- 2007/02/23 09:00 [medline]
PHST- 2005/08/23 09:00 [entrez]
PHST- 2010/07/01 00:00 [pmc-release]
AID - S0966-6362(05)00112-8 [pii]
AID - 10.1016/j.gaitpost.2005.06.016 [doi]
PST - ppublish
SO  - Gait Posture. 2006 Aug;24(1):23-34. doi: 10.1016/j.gaitpost.2005.06.016. Epub 
      2005 Aug 19.