The application of high-intensity muscular contractions for maximal training gains: the impact of age on the continuum of muscle injury, maladaptation and adaptation

Details

• Personal Author:
  Baker BA ; Cutlip, Robert G.
• Description:
  Overt skeletal muscle injury can occur following exposure to high-intensity muscular contractions implemented during mechanical loading, and this phenomenon is exacerbated with age. Yet not all muscular contractions produce injury, and evolving data supports a viewpoint that the classically reported "injury response" is not an exclusive consequence following mechanical loading. Strength gains and muscle hypertrophy are adaptive responses that result from high-intensity muscular contractions involved during mechanical loading (i.e. strength-type training); however the aging process appears to attenuate these positive training benefits, while concomitantly exhibiting a sarcopenic state that ultimately leads to senescence. The best known strategy to increase skeletal muscle mass is with resistance training, however, prescribing this mode of training has been cautioned in aged populations due to the compromised condition of the older individual - a sarcopenic state and the propensity that it will induce overt skeletal muscle injury if commenced. In spite of this, current evidence supports a model of muscle adaptation following mechanical loading, distinct from overt injury, in which myofiber degeneration and inflammation does not contribute as significantly as once reported even following muscular contractions incorporating repetitive eccentric contractions. Moreover, the inherent capability of skeletal muscle to positively adapt to repetitive Overt skeletal muscle injury can occur following exposure to high-intensity muscular contractions implemented during mechanical loading, and this phenomenon is exacerbated with age. Yet not all muscular contractions produce injury, and evolving data supports a viewpoint that the classically reported "injury response" is not an exclusive consequence following mechanical loading. Strength gains and muscle hypertrophy are adaptive responses that result from high-intensity muscular contractions involved during mechanical loading (i.e. strength-type training); however the aging process appears to attenuate these positive training benefits, while concomitantly exhibiting a sarcopenic state that ultimately leads to senescence. The best known strategy to increase skeletal muscle mass is with resistance training, however, prescribing this mode of training has been cautioned in aged populations due to the compromised condition of the older individual - a sarcopenic state and the propensity that it will induce overt skeletal muscle injury if commenced. In spite of this, current evidence supports a model of muscle adaptation following mechanical loading, distinct from overt injury, in which myofiber degeneration and inflammation does not contribute as significantly as once reported even following muscular contractions incorporating repetitive eccentric contractions. Moreover, the inherent capability of skeletal muscle to positively adapt to repetitive mechanical loading is highly dependent on optimizing the biomechanical loading signature (i.e. repetition number, velocity, frequency of exposure, duty cycle, and range of motion) and the intensity of the mechanical loading exposure for any given population; this may be particularly important with aged populations. Indeed, this concept is paramount in those individuals presenting with risk factors associated with disease states, so that they too may experience the benefits of resistance training. Thus, the focus of this chapter will detail the continuum of muscle injury, mal-adaption, and adaptation based upon historical as well as current evidence of performance and biological data, and how the implementation of high-intensity muscular contractions (stretch-shortening contractions - SSCs) may offer the most effective and appealing means of physical activity to counter the deleterious effects observed with sarcopenia as we age. We will also consider and compare models of mechanical loading that use high-intensity muscular contractions to induce positive physiological responses in various populations, and suggest the applicability and modifications of these approaches when integrated into contemporary resistance training exercise prescriptions with the anticipation that they may be implemented in occupational, military, athletic, and general populations. [Description provided by NIOSH]
• Subjects:
  Age Factors Biomechanical Phenomena Fatigue Musculoskeletal Diseases Musculoskeletal System Mycoses Occupational Health Safety Staff Development
• Keywords:
  Age-factors Biomechanics Motion-studies Muscle-function Muscle-physiology Muscle-tension Musculoskeletal-system Musculoskeletal-system-disorders Mycology Physical-exercise Physical-fitness Physiological-effects Physiological-factors Physiological-fatigue Physiological-function Physiological-measurements Physiological-response Physiological-stress Physiological-testing Skeletal-disorders Skeletal-movement Skeletal-stress Skeletal-system Skeletal-system-disorders Training

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• ISBN:
  9781608762217
• Publisher:
  Nova Science Publishers
• Document Type:
  Text
• Genre:
  Book
• 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:
  119-148
• NIOSHTIC Number:
  nn:20039100
• Citation:
  Strength training: types and principles, benefits and concerns. Kai JT, ed. New York: Nova Science Publishers, 2010 Jan; :119-148
• Contact Point Address:
  Robert G. Cutlip, National Institute for Occupational Safety and Health Health Effects Laboratory Division, 1095 Don Nehlen Drive, M/S 2027, Morgantown, WV 26505
• Email:
  rgc8@cdc.gov
• Editor(s):
  Kai JT
• Federal Fiscal Year:
  2010
• Peer Reviewed:
  False
• Source Full Name:
  Strength training: types and principles, benefits and concerns
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bec063e2348c2b3fbea48ff6ca5e2cbd2e2a0d733525ffecd6f3f67831cf47f2c6b6a26c0df3656c4d5eb597f6efacb8c82c94fa17bade04c88fd3b47ceacdac
• Download URL:
  https://stacks.cdc.gov/view/cdc/192578/cdc_192578_DS1.pdf
• File Type:
  [PDF - 11.42 MB ]