High-Intensity Stretch-Shortening Contraction Training Modifies Responsivity of Skeletal Muscle in Old Male Rats

Details

• Personal Author:
  Baker BA ; Ensey J ; Naimo MA ; Rader EP
• Description:
  Utilization of high-intensity resistance training to counter age-related sarcopenia is currently debated because of the potential for maladaptation when training design is inappropriate. Training design is problematic because the influence of various loading variables (e.g. contraction mode, repetition number, and training frequency) is still not well characterized at old age. To address this in a precisely controlled manner, we developed a rodent model of high-intensity training consisting of maximally-activated stretch-shortening contractions (SSCs), contractions typical during resistance training. With this model, we determined that at old age, high-repetition SSC training (80 SSCs: 8 sets of 10 repetitions) performed frequently (i.e. 3 days per week) for 4.5 weeks induced strength deficits with no muscle mass gain while decreasing frequency to 2 days per week promoted increases in muscle mass and muscle quality (i.e. performance normalized to muscle mass). This finding confirmed the popular notion that decreasing training frequency has a robust effect with age. Meanwhile, the influence of other loading variables remains contentious. The aim of the present study was to assess muscle adaptation following modulation of contraction mode and repetition number during high-intensity SSC training. Muscles of young (3 month old) and old (30 month old) male rats were exposed to 4.5 weeks of low-repetition static training of 4 (i.e. 4 sets of one repetition) isometric (ISO) contractions 3 days per week or a more moderate-repetition dynamic training of 40 SSCs (i.e. 4 sets of 10 repetitions) 3 days per week. For young rats, performance and muscle mass increased regardless of training protocol. For old rats, no muscle mass adaptation was observed for 4 ISO training while 40 SSC training induced muscle mass gain without improvement in muscle quality, an outcome distinct from modulating training frequency. Muscle mass gain for old rats was accompanied by decreased protein levels of tumor necrosis factor alpha, a mediator of age-related chronic inflammatory signaling, to young levels. These findings suggest that while dynamic high-intensity training with a moderate number of repetitions has a limited capacity for altering muscle quality, such training is a viable strategy for countering age-related inflammatory signaling and modifying muscle mass. [Description provided by NIOSH]
• Subjects:
  Mining Mortality Occupational Health Radiation Respiratory Tract Diseases Safety
• Keywords:
  Aging Author Keywords: Dorsiflexor Muscles Dynamometer Fisher 344XBrown Norway Rats Laboratory Animals Muscle Contraction Muscle Function Musculoskeletal System Physiological Function Stretch-shortening Contractions
• ISSN:
  0531-5565
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  118-126
• Volume:
  104
• NIOSHTIC Number:
  nn:20051075
• Citation:
  Exp Gerontol 2018 Apr; 104:118-126
• Contact Point Address:
  Erik P. Rader, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, MS L3014, 1095 Willowdale Rd., Morgantown, WV 26505
• Email:
  Wlz4@cdc.gov
• Federal Fiscal Year:
  2018
• Peer Reviewed:
  True
• Source Full Name:
  Experimental Gerontology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6e9985a6a4e788035f419c7f75583d4bb9a1aa40f7f3618f3cde93b234c2d0e1499ef8b95c907ae4af6fc79daeb39c5f8b3c2d4ea4beb16e1be184d5d5a4d643
• Download URL:
  https://stacks.cdc.gov/view/cdc/211201/cdc_211201_DS1.pdf
• File Type:
  [PDF - 1.51 MB ]