Published on May 31, 2014
By: Izatty Lim (0308188)
Definition Cellular mechanism of muscle fatigue & recovery
decline in muscle performance associated with muscle activity. As fatigue sets in, o force in your muscles reduces, o muscle responses to brain stimuli reduces o activity levels decrease. temporary and reversible condition continuous high-frequency stimulation repeated tetanic stimulation
Fatigue mechanisms have been found to be multifactorial.
Fuel depletion Metabolic by-products Neuromuscular events •Intramuscular ATP • Muscle glycogen • Blood glucose • Hydrogen ions (H+) in plasma and muscle • Inorganic phosphate (Pi) • Adenosine diphosphate (ADP) • Decreased ‘firing’ of the central nervous system • Impaired sodium (Na+) and potassium (K+) gradients
Problem: build up of lactic acid Problem: needs oxygen Problem: only make 1 ATP at a time (15-20s of activity) Ca2+
Myosin: for cross-bridge cycling Ca2+ ATPase: o terminate contraction, pump Ca2+ back into sarcoplasmic reticulum
reduced maximum force-generating capacity reduced myofibrillar Ca2+ sensitivity reduced Ca2+ release ↓ force
• ACIDOSIS • H+ competes with Ca2+ for binding sites on troponin C • ↓ maximal Ca2+ activated force and Ca2+ sensitivity (slows the maximal shortening velocity and prolongs relaxation) • Burning sensation
Predominant energy system Likely causes of fatigue Types of recovery ATP/PC Fuel Depletion: ATP & PC Rest recovery Lactic Acid Accumulation of metabolic by- products: H+ (hydrogen ions) Pi (inorganic phosphates) Non-dietary Active Recovery Massage Hydro/water based therapies e.g. contrasting via hot/cold baths Aerobic Fuel Depletion: Glycogen stores, then fats Elevated body temperature leading to: Dehydration Dietary High Glycemic Index foods Rehydration Non-dietary Active Recovery Massage Hydro/water based therapies
http://www.ncbi.nlm.nih.gov/pubmed/18195089 http://www.mendeley.com/catalog/cellular-mechanisms- muscle-fatigue/ http://lib.bioinfo.pl/pmid:7576593 http://www.pc.maricopa.edu/Biology/thoffman/Co mmon201/MuscularSystem.pdf
Mitos y realidades de las sustancias psicoactivas
Mitos y realidades de las sustancias psicoactivas.
Allen DG(1), Lamb GD, Westerblad H. Author information: (1)School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, New South Wales ...
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