Normal aging alters in vivo passive biomechanical response of the rat gastrocnemius-Achilles muscle-tendon unit
Predisposition to Achilles tendon (AT) ruptures in middle-aged individuals may be associated with age-related changes to inherent passive biomechanical properties of the gastrocnemius-Achilles (GC-AT) muscle-tendon unit, due to known muscle-tendon structural changes in normal aging. The goal of this...
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| Main Authors: | , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2013
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| In: |
Journal of biomechanics
Year: 2013, Volume: 46, Issue: 3, Pages: 450-455 |
| ISSN: | 1873-2380 |
| DOI: | 10.1016/j.jbiomech.2012.11.007 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.jbiomech.2012.11.007 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0021929012006598 
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| Author Notes: | Johannes F. Plate, Walter F. Wiggins, Patrick Haubruck, Aaron T. Scott, Thomas L. Smith, Katherine R. Saul, Sandeep Mannava |
| Summary: | Predisposition to Achilles tendon (AT) ruptures in middle-aged individuals may be associated with age-related changes to inherent passive biomechanical properties of the gastrocnemius-Achilles (GC-AT) muscle-tendon unit, due to known muscle-tendon structural changes in normal aging. The goal of this study was to determine whether the passive biomechanical response of the GC-AT muscle-tendon unit was altered with age in 6 young (8 months) and 6 middle-aged (24 months) F344xBN hybrid rats from the National Institute on Aging colony. Fung's quasilinear viscoelastic (QLV) model was used to determine in vivo history and time-dependent load-relaxation response of the GC-AT. Effective stiffness and modulus were also estimated using linear regression analysis. Fung's QLV revealed a significantly decreased magnitude of the relaxation response (parameter C, p=0.026) in middle-aged animals compared to young animals (0.108±0.007 vs. 0.144±0.015), with similar time-dependent viscous GC-AT properties (τ1, τ2). The product of elastic parameters (A⁎B), which represents the initial slope of the elastic response, was significantly increased by 50% in middle-aged rats (p=0.014). Estimated GC-AT stiffness increased 28% at peak tensions in middle-aged rats (2.7±0.2N/mm) compared to young rats (1.9±0.2N/mm; p=0.036). While the limitations of this animal model must be considered, the changes we describe could be associated with the observation that GC-AT pathology and injury is more common in middle-aged individuals. Further studies are necessary to characterize the load-to-failure behavior of AT in middle-aged compared to young animals. |
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| Item Description: | Available online 13 December 2012 Gesehen am 25.11.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1873-2380 |
| DOI: | 10.1016/j.jbiomech.2012.11.007 |