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Effect of repetition rate on the formation of microtears in tendon in an in vivo cyclical loading model

Nakama, Leena H.; King, Karen B.; Abrahamsson, Sven LU and Rempel, David A. (2007) In Journal of Orthopaedic Research 25(9). p.1176-1184
Abstract
We reported previously the formation of microtears in an in vivo loaded Flexor Digitorum Profundus (FDP) rabbit tendon with a repetition rate of 60 repetitions per minute and a peak force of 15% of maximum peak tetanic force for 80 cumulative hours. Tear area as a percent of tendon area, tear density (tears/mm(2)), and mean tear size (mu m(2)) were higher in tendons from the loaded limb compared to the unloaded control limb. The purpose of the present study was to compare those results to results obtained with a repetition rate of 10 while maintaining the same peak force and force-time integral (n = 8). Due to a strain gradient between the inner and outer sides of the FDP tendon, microtears were quantified in four regions, two regions each... (More)
We reported previously the formation of microtears in an in vivo loaded Flexor Digitorum Profundus (FDP) rabbit tendon with a repetition rate of 60 repetitions per minute and a peak force of 15% of maximum peak tetanic force for 80 cumulative hours. Tear area as a percent of tendon area, tear density (tears/mm(2)), and mean tear size (mu m(2)) were higher in tendons from the loaded limb compared to the unloaded control limb. The purpose of the present study was to compare those results to results obtained with a repetition rate of 10 while maintaining the same peak force and force-time integral (n = 8). Due to a strain gradient between the inner and outer sides of the FDP tendon, microtears were quantified in four regions, two regions each along the inner and outer sides of the tendon. The tear area as a percent of total tendon area and the mean tear size were significantly greater in the loaded limb compared to the unloaded limb (p < 0.03). However, the effects were less than those observed at 60 repetitions/min. The higher repetition loading pattern resulted in an increase in tear measures in all four regions, while the lower rate produced changes only in the outer regions of the tendon. This finding may establish where the initial sites of damage occur in tendons that insert into bone in a similar arrangement as the FDP. The results suggest that repetition rate or number of loading cycles is associated with increased tendon microtears or fragility in a dose-response pattern. (c) 2007 Orthopaedic Research Society. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
overuse, epicondylitis, tendonitis, tendinitis, repetitive loading
in
Journal of Orthopaedic Research
volume
25
issue
9
pages
1176 - 1184
publisher
John Wiley & Sons
external identifiers
  • wos:000248893200007
  • scopus:34548382714
ISSN
1554-527X
DOI
10.1002/jor.20408
language
English
LU publication?
yes
id
b42d3736-0b97-4696-a2f3-bc4541ad6224 (old id 691633)
date added to LUP
2007-12-18 12:28:48
date last changed
2017-07-02 03:38:58
@article{b42d3736-0b97-4696-a2f3-bc4541ad6224,
  abstract     = {We reported previously the formation of microtears in an in vivo loaded Flexor Digitorum Profundus (FDP) rabbit tendon with a repetition rate of 60 repetitions per minute and a peak force of 15% of maximum peak tetanic force for 80 cumulative hours. Tear area as a percent of tendon area, tear density (tears/mm(2)), and mean tear size (mu m(2)) were higher in tendons from the loaded limb compared to the unloaded control limb. The purpose of the present study was to compare those results to results obtained with a repetition rate of 10 while maintaining the same peak force and force-time integral (n = 8). Due to a strain gradient between the inner and outer sides of the FDP tendon, microtears were quantified in four regions, two regions each along the inner and outer sides of the tendon. The tear area as a percent of total tendon area and the mean tear size were significantly greater in the loaded limb compared to the unloaded limb (p &lt; 0.03). However, the effects were less than those observed at 60 repetitions/min. The higher repetition loading pattern resulted in an increase in tear measures in all four regions, while the lower rate produced changes only in the outer regions of the tendon. This finding may establish where the initial sites of damage occur in tendons that insert into bone in a similar arrangement as the FDP. The results suggest that repetition rate or number of loading cycles is associated with increased tendon microtears or fragility in a dose-response pattern. (c) 2007 Orthopaedic Research Society.},
  author       = {Nakama, Leena H. and King, Karen B. and Abrahamsson, Sven and Rempel, David A.},
  issn         = {1554-527X},
  keyword      = {overuse,epicondylitis,tendonitis,tendinitis,repetitive loading},
  language     = {eng},
  number       = {9},
  pages        = {1176--1184},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Orthopaedic Research},
  title        = {Effect of repetition rate on the formation of microtears in tendon in an in vivo cyclical loading model},
  url          = {http://dx.doi.org/10.1002/jor.20408},
  volume       = {25},
  year         = {2007},
}