Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Response of tibialis anterior tendon to a chronic exposure of stretch-shortening cycles: age effects.

Authors
Ensey-JS; Hollander-MS; Wu-JZ; Kashon-ML; Baker-BB; Cutlip-RG
Source
Biomed Eng Online 2009 Jun; 8:12
NIOSHTIC No.
20035762
Abstract
Background: The purpose of the current study was to investigate the effects of aging on tendon response to repetitive exposures of stretch-shortening cycles (SSC's). Methods: The left hind limb from young (3 mo, N = 4) and old (30 mo, N = 9) male Fisher 344 x Brown Norway rats were exposed to 80 maximal SSCs (60 deg/ s, 50 deg range of motion) 3x/ week for 4.5 weeks in vivo. After the last exposure, tendons from the tibialis anterior muscle were isolated, stored at -80 degrees C, and then tested using a micro-mechanical testing machine. Deformation of each tendon was evaluated using both relative grip-to-grip displacements and reference marks via a video system. Results: At failure, the young control tendons had higher strain magnitude than the young exposed (p < 0.01) and the old control tendons (p < .0001). Total load at inflection was affected by age only (p < 0.01). Old exposed and control tendons exhibited significantly higher loads at the inflection point than their young counterparts (p < 0.05 for both comparisons). At failure, the old exposed tendons carried higher loads than the young exposed tendons (p < 0.05). Stiffness was affected by age only at failure where the old tendons exhibited higher stiffness in both exposed and control tendons than their young counterparts (p < 0.05 and p < 0.01, respectively). Conclusion: The chronic protocol enhanced the elastic stiffness of young tendon and the loads in both the young and old tendons. The old exposed tendons were found to exhibit higher load capacity than their younger counterparts, which differed from our initial hypothesis.
Keywords
Age-factors; Age-groups; Animals; Animal-studies; Biological-effects; Biological-function; Biological-monitoring; Cumulative-trauma; Cumulative-trauma-disorders; Exposure-assessment; Exposure-levels; Exposure-methods; Laboratory-animals; Laboratory-testing; Musculoskeletal-system; Musculoskeletal-system-disorders; Physical-reactions; Physical-stress; Physiological-effects; Physiological-fatigue; Physiological-response; Physiological-stress; Physiological-testing; Repetitive-work
Contact
Robert G Cutlip, National Institute for Occupational Safety and Health (NIOSH), Health Effects Laboratory Division, Morgantown, West Virginia 26505
Publication Date
20090629
Document Type
Journal Article
Email Address
rgc8@cdc.gov
Fiscal Year
2009
NTIS Accession No.
NTIS Price
ISSN
1475-925X
NIOSH Division
HELD
Source Name
Biomedical Engineering Online
State
WV
TOP