The effect of running, strength, and vibration strength training on the mechanical, morphological, and biochemical properties of the Achilles tendon in rats

Legerlotz, Kirsten; Schjerling, Peter; Langberg, Henning; Brüggemann, Gert–Peter; Niehoff, Anja

doi:10.1152/japplphysiol.00767.2006

Cited by 54 publications

(57 citation statements)

References 43 publications

(49 reference statements)

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“…However, the authors suggested that the microdialysis technique could not accurately reflect MMP-2 tissue levels, because, at least, part of MMP-2 is attached to membrane-anchored MMPs (Nagase, 1998). On the other hand, Legerlotz et al (2007) did not observe any regulation of tendon MMP-2 mRNA expression in response to long-term strength training in rats. In our study, the pro-MMP-2 appeared increased after 6 hr of both types of physical training.…”

Section: Discussionmentioning

confidence: 96%

Calcaneal Tendon Regions Exhibit Different MMP‐2 Activation After Vertical Jumping and Treadmill Running

Malheiro

Giacomini

Justulin

et al. 2009

The Anatomical Record

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Increased activity of matrix metalloproteinases (MMPs) -2 and -9 was found in calcaneal tendon after physical training. However, little attention has been given to the distinct biomechanical and tissue structure of the calcaneal tendon's proximal and distal regions. Herein, we evaluated the effect of two types of physical activities on tendon morphology and matrix metalloproteinase activities in the proximal and distal regions of rat calcaneal tendon, separately. Adult male Wistar rats from control, water-adapted, vertical-jumping, and treadmill-running groups were sacrificed after 1 or 4 days of physical exercise, 6 hr after the end of that day's exercise session. Tendons were processed for histology, morphometry, and gelatin zymography. Tendons from adapted and trained animals showed active secretory cells and increased thickness, cellularity, and blood vessel volume fraction of peritendinous sheath, but without inflammatory process. In the proximal region, both pro-and active MMP-2 were increased after vertical jumping, but only pro-MMP-2 was increased after treadmill running. In contrast, in the distal region, both exercise types increased the activity of pro-and active MMP-2, especially treadmill running, which increased the active MMP-2 by about 11-and eightfold, respectively, after 1 and 4 days of training. No activity of MMP-9 was observed in either tendon region in this study. In conclusion, distal and proximal regions of calcaneal tendon exhibit differential intensities of tissue remodeling after treadmill running or vertical jumping and MMP-2, in the absence of inflammation, plays a major role in this adaptive response.

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Section: Discussionmentioning

confidence: 96%

Calcaneal Tendon Regions Exhibit Different MMP‐2 Activation After Vertical Jumping and Treadmill Running

Malheiro

Giacomini

Justulin

et al. 2009

The Anatomical Record

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“…In the experimental resistance training settings, the resistance training model described by Klitgaard (1988) (based on food reward) have presented important advances into the modeling of resistance exercise performed in humans, partly because of the demonstration that rats submitted to this resistance training model presented absolute increase in exercised muscles, a fact not frequently observed in other studies employing volitional experimental resistance training models (Tamaki et al 1992;Duncan et al 1998;Legerlotz et al 2007). However, an important concern about this kind of resistance training protocol is related to the obligatory role of fast to stimulate the rats to perform the resistance exercise.…”

Section: Discussionmentioning

confidence: 99%

Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3β and p70S6K levels in rats

et al. 2009

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Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3beta and eIF2Bepsilon mRNA levels and Akt, GSK-3beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.

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“…Apparently, no human and very few animal studies have previously investigated how tendon tissue responds to extended periods of physiological training with regard to regulation of mRNA expression. One study found increased TIMP-1 mRNA and unchanged levels of collagen (I and III), TGF-␤1, and CTGF mRNA in Achilles tendons in response to voluntary wheel running in female rats (31). A more recent study showed elevated levels of TIMP-1 and IGFIEa, after 7 wk of jump training in male rat Achilles tendons, while collagen I and III were unchanged (33).…”

Section: Regulation Of Gene Expressionmentioning

confidence: 99%

Uphill running improves rat Achilles tendon tissue mechanical properties and alters gene expression without inducing pathological changes

Heinemeier

Skovgaard

Bayer

et al. 2012

Journal of Applied Physiology

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Little is known about the etiology 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°incline, 1 h/day, 5 days/wk (17-20 m/min) for 12 wk and were compared with 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. 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 Ͻ 0.005) and failure stress/body weight (P Ͻ 0.02) in runners compared with controls further supported that tendons successfully adapted to uphill running. Several genes of interest were regulated after 12 wk of running. Expression of collagen III and insulin-like growth factor I was increased, while collagen I was unchanged, and decreases were seen in noncollagen matrix components (fibromodulin and biglycan), matrix degrading enzymes, transforming growth factor-␤1, 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 wk 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. loading; exercise; tendinopathy; collagen TENDONS TRANSMIT FORCE FROM muscle to bone during muscle contraction, and optimal, painless function of tendon tissue is essential in voluntary movement. Although tendons can withstand considerable force, repetitive movements can lead to overuse of tendon tissue, resulting in tendinopathy, which is characterized by pain during activity and significantly impaired performance (36). Tendinopathy is very common in relation to both sports and occupational loading (16,17,45), and, since treatment possibilities are still relatively poor, these conditions are often prolonged (36). Although the features of tendinopathy at the time point when symptoms occur are relatively well described, the etiology of overuse-related tendinopathy is still poorly understood. Thus we know that symptomatic human tendinopathy is characterized by histological changes, such as increased cell density, altered cell morphology, and disorganization of the collagen matrix (reviewed by Ref. 36). In addition, increased vascularization has been shown in tendinopathic tendon (8), and studies of gene expression commonly find higher levels of collagen I and III, proteoglycan, and matrix metalloproteinase (MMP)-2 mRNA, as well as decreased MMP-3 mRNA expression (3, 12-14, 26 -28). However, the events leading up to these chan...

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The effect of running, strength, and vibration strength training on the mechanical, morphological, and biochemical properties of the Achilles tendon in rats

Cited by 54 publications

References 43 publications

Calcaneal Tendon Regions Exhibit Different MMP‐2 Activation After Vertical Jumping and Treadmill Running

Calcaneal Tendon Regions Exhibit Different MMP‐2 Activation After Vertical Jumping and Treadmill Running

Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3β and p70S6K levels in rats

Uphill running improves rat Achilles tendon tissue mechanical properties and alters gene expression without inducing pathological changes

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