Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

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

Authors
Baker-BA; Cutlip-RG
Source
Strength Training: Types and Principles, Benefits and Concerns. Kai JT, ed., New York: Nova Science Publishers, 2010 Jan; :119-148
Link
NIOSHTIC No.
20039100
Abstract
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.
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
Contact
Robert G. Cutlip, National Institute for Occupational Safety and Health Health Effects Laboratory Division, 1095 Don Nehlen Drive, M/S 2027, Morgantown, WV 26505
Publication Date
20100101
Document Type
Book or book chapter
Email Address
rgc8@cdc.gov
Editors
Kai-JT
Fiscal Year
2010
NTIS Accession No.
NTIS Price
ISBN No.
9781608762217
NIOSH Division
HELD
Source Name
Strength Training: Types and Principles, Benefits and Concerns
State
WV
TOP