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Uphill running improves rat Achilles tendon tissue mechanical properties, and alters gene expression without inducing pathological changes.
Heinemeier KM, Skovgaard D, Bayer ML, Qvortrup K, Kjaer A, Kjaer M, Magnusson SP, Kongsgaard M. J Appl Physiol. 2012 Jul 12.
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Overuse Achilles tendinopathy is a common and challenging problem in sports medicine. Little is known about the aetiology of this disorder, and the development of a good animal model for overuse tendinopathy is essential for advancing insight into the disease mechanisms. Our aim was to test a previously proposed rat model for Achilles tendon overuse. Ten adult male Sprague Dawley rats ran on a treadmill with 10 degrees incline, 1 h/day, 5 days/wk (17-20 m/min) for 12 wks and were compared to 12 control rats. Histological, mechanical, and gene-expression changes were measured on the Achilles tendons after the intervention, and local tendon glucose-uptake was measured before and after the intervention with positron emission tomography (PET). No differences were detected between runners and controls in tissue histology or in glucose uptake, indicating that tendon pathology was not induced. Greater tendon tissue modulus (p<0.005) and failure stress/body weight (p<0.02) in runners compared to controls further supported that tendons successfully adapted to uphill running. Several genes of interest were regulated after 12 weeks of running; Expression of collagen III and insulin like growth factor-I was increased, while collagen I was unchanged, and decreases were seen in non-collagen matrix components (fibromodulin and biglycan), matrix degrading enzymes, transforming growth factor-β-I and connective tissue growth factor. In conclusion, the tested model could not be validated as a model for Achilles tendinopathy, as the rats were able to adapt to 12 weeks of uphill running without any signs of tendinopathy. Improved mechanical properties were observed, as well as changes in gene-expression that were distinctly different from what is seen in tendinopathy and in response to short-term tendon loading.
Uphill running improves rat Achilles tendon tissue mechanical properties, and alters gene expression without inducing pathological changes.
Heinemeier KM, Skovgaard D, Bayer ML, Qvortrup K, Kjaer A, Kjaer M, Magnusson SP, Kongsgaard M. J Appl Physiol. 2012 Jul 12.
OK, this was in rats and it does seem to be somewhat counter-intuitive that uphill running will help achilles tendonitis, but assume that the benefit is probably related to the increased eccentric activity.
From on n=1, my second most recent bout of achilles tendonitis was cured with a Cluffy wedge (I talked about that here ), my most recent bout went away when I added in some steep hill runs (for those in Melbourne, it was the 100 steps in Ferntree Gully)
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
OK, this was in rats and it does seem to be somewhat counter-intuitive that uphill running will help achilles tendonitis, but assume that the benefit is probably related to the increased eccentric activity.
From on n=1, my second most recent bout of achilles tendonitis was cured with a Cluffy wedge (I talked about that here ), my most recent bout went away when I added in some steep hill runs (for those in Melbourne, it was the 100 steps in Ferntree Gully)
Hi Craig can you send the full text ?
Hi all miss me
Anyways he is something I wrote which may or may not be published
Quote:
The structure of the tendon is complex and important to understand due to the effect of torsion has on the effectiveness of the Achilles tendon in its important role in the efficiency of gait. The Gastrocnemius and Soleus complex acts on three joints of the lower extremity: the knee (Gastrocnemius only) and the Ankle and Subtalar joint (both muscles). Even though they have the same insertion point they may at certain times have the same or different modes of action on these joints (28) .
The Achilles tendon changes shape over a time, not just in cross sectional area and length but most importantly in torsion. In adults the Achilles tendon demonstrates various amounts of torsion. This torsion is seen to be important in elongation and elastic energy return. The complex makeup of the tendon allows it to play a greater role in creating moments at the Ankle and Subtalar Joint (26) All tendons have evolved primarily to transmit tensile load and have a fibrous tissue structure to accommodate this(29) . The post-natal progressive changes in cellular and fibrous components are closely related to the intensity and duration of mechanical stress. As loads on the tendon increase the collagen fibers grow in diameter (30). It appears that this growth and change in the torsion of the Achilles is a result of physical activity (26) . This suggests that greater activity, results in greater torsion of the Achilles tendon and the ability elastic energy return increases.
Another important feature when looking at the Achilles tendon is the stiffness, various Achilles tendon stiffness will mean differing amounts of elongation under load and therefore differing amounts of returned stored elastic energy .The greater the amount of stored and returned elastic energy the greater efficiency of gait. There however needs to be a balance with the fact that excessive elongation of the Achilles may lead to plastic deformation and injury. Therefore there needs to be a balance between torsion and stiffness. The torsion of the tendon will allow it to function more like a spring, with the stiffness determining how much compression and elongation the tendon can tolerate without becoming injured. Muraoka et al note that the cross-sectional area of the Achilles does not relate to stiffness, ie the greater the cross-sectional area the stiffer the tendon (31) no correlation was noted. But they did discover that the greater the muscle strength of the Gastrocnemius and Soleus complex the stiffer the tendon (32). So the two important features of the tendon which give it the ability to tolerate and produce forces, store and release elastic energy are effected by one the torsion of the tendon itself and the stiffness, which is controlled by the strength of the Gastrocnemius and Soleus complex.
26- Feehery Jr RV : Surgery of the Achilles Tendon and Posterior Muscle group. Clinical Podiatric medical Surgery: 9: 781-811,1992
27- Alexander RM, Bennet-Clarke HC, Storage of elastic strain energy in muscle and other tissues. Nature : 265:114-117, 1994.
28- Neptune RR, Kautz SA, Zajac FF : Contributions of the individual ankle plantarflexors to support, forward progression and Swing initiation during walking. Journal of Biomechanics. 34: 1387-1398, 2001
29- Cook J, Purdam C : Is compression load a factor in the development of Tendionopathy ? Br J Sports Med doi:10.1136/bjsports-2011-090414
30- Strocchi R, DePasquale V, Guizzardi S et al : Human Achilles tendon: morphological and morpometric variation as a function of age. Foot and Ankle. 12: 100-104, 1991
31- Murako T, Muramatsc T, Fukunaga T et al : Geometric and Elastic Properties of in vivo Human Achilles Tendon in Young adults. Cells Tissues Organs. 178: 197-203,2004
32- Murako T, Muramatsc T, Fukunaga T et al: Elastic properties of human Achilles tendon are correlated to muscle strength. J Appl Physiol. 99: 665-669, 2005
Basically it all comes back to torsion and spring harmonics -
The greater the torsion the stronger the Gastroc/sol complex and the more efficient in storing and returning energy and taking load
What is really interesting was the mention of a change in gene markers
Out of curiosity Craig. Did you continue with the CW once symptoms had subsided? If so did you rehab the tendon then cease use of the CW?
Still wearing the Cluffy Wedge and still running up steep hills...
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
OK, this was in rats and it does seem to be somewhat counter-intuitive that uphill running will help achilles tendonitis, but assume that the benefit is probably related to the increased eccentric activity.
Mecanotransduction... tissue adaptation... eccentric / minimalist / uphill... : That's what I recommend to my persistent Achilles tendon pain, and prohibit to my acute tendon pain.
INTRODUCTION
Overuse conditions of the Achilles tendon likely develop due to a combination of extrinsic and intrinsic risk factors. The purpose of this study was to investigate the individual and combined effects of uphill treadmill running (extrinsic risk factor) and collagenase injection (intrinsic risk factor) on the histological appearance of rodent Achilles tendons. Previous studies have shown that collagenase injection leads to inflammation of the tendon [1], while exercise can lead to adaptation and tendon hypertrophy [2]. Our hypothesis was that collagenase injection would result in initial tendon inflammation which would become degenerative when combined with mechanical loading.
METHODS
Twenty-four mature high-capacity running rats were studied. All rats received a collagenase injection into one Achilles tendon at baseline. After one week, animals were randomly divided into either a run or cage-control group. The run group ran on a treadmill at a 15° incline, 5 days/week at increasing duration and speed. Tendons were harvested at either 4 or 10 weeks after the start of the running regimen. Specimens were fixed in formalin and embedded in paraffin. Haematoxylin and eosin stained sections were evaluated using a modified Bonar scale by two blinded and independent assessors, with a third to resolve disputes.
RESULTS
At 4 weeks, higher levels of pathology were seen in the injected tendons than in the non-injected tendons (ANOVA: p=0.007). No side to side difference was seen at 10 weeks (ANOVA: p=0.309). There was no difference between running and non-running groups at 4 weeks (ANOVA: p=0.579) or 10 weeks (ANOVA: p=0.429). No interaction effects were seen between injection and running at 4 weeks (ANOVA: p=0.934) or 10 weeks (ANOVA: p=0.847).
DISCUSSION
In high capacity running rats, uphill treadmill running using these experimental parameters did not independently create histopathology of the Achilles tendon. Furthermore, the effect of collagenase did not have a long-term effect and was not influenced by running. Therefore, the combination of collagenase injection and uphill treadmill running does not seem to create a histological presentation similar to the degeneration seen in human Achilles tendinopathy.
This has now been published in full: Uphill treadmill running does not induce histopathological changes in the rat Achilles tendon Rachel C Dirks, Jeffrey S Richard, Angela M Fearon, Alexander Scott, Lauren G Koch, Steven L Britton, Stuart J Warden BMC Musculoskeletal Disorders 2013, 14:90 (11 March 2013)
Quote:
Background
The purpose of this study was to investigate whether uphill treadmill running in rats created histopathological changes within the Achilles tendon consistent with Achilles tendinosis in humans.
Methods
Twenty-six mature rats selectively bred for high-capacity running were divided into run and cage control groups. Run group rats ran on a treadmill at a 15° incline for a maximum duration of 1 hr/d, 5 d/wk for 9 weeks at increasing speeds, while rats in the cage control group maintained normal cage activity. After 9 weeks, Achilles tendons were harvested for histological processing and semi-quantitative histopathological analysis.
Results
There were no significant group differences within each of the individual histopathological categories assessed (all p ≥ 0.16) or for total histopathological score (p = 0.14).
Conclusions
Uphill treadmill running in rats selectively bred for high-capacity running did not generate Achilles tendon changes consistent with the histopathological presentation of Achilles tendinosis in humans.
Uphill running improves rat Achilles tendon tissue mechanical properties, and alters gene expression without inducing pathological changes.
Heinemeier KM, Skovgaard D, Bayer ML, Qvortrup K, Kjaer A, Kjaer M, Magnusson SP, Kongsgaard M. J Appl Physiol. 2012 Jul 12.
Quote:
Improved mechanical properties were observed, as well as changes in gene-expression that were distinctly different from what is seen in tendinopathy and in response to short-term tendon loading.
versus:
Quote:
Originally Posted by NewsBot
Uphill treadmill running does not induce histopathological changes in the rat Achilles tendon Rachel C Dirks, Jeffrey S Richard, Angela M Fearon, Alexander Scott, Lauren G Koch, Steven L Britton, Stuart J Warden BMC Musculoskeletal Disorders 2013, 14:90 (11 March 2013)
Quote:
Uphill treadmill running in rats selectively bred for high-capacity running did not generate Achilles tendon changes consistent with the histopathological presentation of Achilles tendinosis in humans.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Uphill running improves achilles tendon mechanical properties
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