Enhancement of Skeletal Muscle in Aged Rats Following High-Intensity Stretch-Shortening Contraction Training
| Autor: | Robert D. Chetlin, Kayla N. Layner, Erik P. Rader, James Ensey, Marshall A. Naimo, Brent A. Baker, Alyssa M. Triscuit |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Male
medicine.medical_specialty Aging Contraction (grammar) Muscle Fibers Skeletal Fluorescent Antibody Technique Isometric exercise 03 medical and health sciences 0302 clinical medicine Physical medicine and rehabilitation Internal medicine Malondialdehyde Physical Conditioning Animal Rats Inbred BN medicine Animals Tibia Muscle Skeletal Maladaptation business.industry High intensity Skeletal muscle 030229 sport sciences Original Articles Organ Size Shortening contraction Oxidative Stress medicine.anatomical_structure Cardiology Lipid Peroxidation Geriatrics and Gerontology medicine.symptom business 030217 neurology & neurosurgery Biomarkers Muscle contraction Muscle Contraction |
| Zdroj: | Rejuvenation Res |
| Popis: | Exercise is the most accessible, efficacious, and multifactorial intervention to improve health and treat chronic disease. High-intensity resistance exercise, in particular, also maximizes skeletal muscle size and strength-outcomes crucial at advanced age. However, such training is capable of inducing muscle maladaptation when misapplied at old age. Therefore, characterization of parameters (e.g., mode and frequency) that foster adaptation is an active research area. To address this issue, we utilized a rodent model that allowed training at maximal intensity in terms of muscle activation and tested the hypothesis that muscles of old rats adapt to stretch-shortening contraction (SSC) training, provided the training frequency is sufficiently low. At termination of training, normalized muscle mass (i.e., muscle mass divided by tibia length) and muscle quality (isometric force divided by normalized muscle mass) were determined. For young rats, normalized muscle mass increased by ∼20% regardless of training frequency. No difference was observed for muscle quality values after 2 days versus 3 days per week training (0.65 ± 0.09 N/mg/mm vs. 0.59 ± 0.05 N/mg/mm, respectively). For old rats following 3 days per week training, normalized muscle mass was unaltered and muscle quality was 30% lower than young levels. Following 2 days per week training at old age, normalized muscle mass increased by 17% and muscle quality was restored to young levels. To investigate this enhanced response, oxidative stress was assessed by lipid peroxidation quantification. For young rats, lipid peroxidation levels were unaltered by training. With aging, baseline levels of lipid peroxidation increased by 1.5-fold. For old rats, only 2 days per week training decreased lipid peroxidation to levels indistinguishable from young values. These results imply that, appropriately scheduled high-intensity SSC training at old age is capable of restoring muscle to a younger phenotype in terms of lipid peroxidation levels and muscle quality. |
| Databáze: | OpenAIRE |
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