|Health and fitness|
This artical is representitive of the body of knowledge regarding muscle fatigue. Recent studies are finding data which refutes current ideas on muscle fatigue. Scientist do not even have a full understand of how muscle contracts let alone why it would show a decline in contractile force, so for now this artical is as i said accurate(ish). I would however like to point out the idea that a lack of ATP in the muscle would be responsible for muscle fatigue has been found to be false. In a completely fatigued muscle there is still 100 times the amount of ATP present that would be required for a maximal contraction.
- Boys, if you think this subject needs covering do it yourself. Wikipedia is a work in progress, and there's always plenty to do. Take away the trolls and the vandals, and perhaps there would be more time for content. JFW | T@lk 15:02, 29 November 2005 (UTC)
At the very least one should recognise that both central (i.e. decreased neural activation) and peripheral (i.e. decreased muscle function) exist, although initally peripheral fatigue is commonly counteracted by increased neural activation. A very good starter is Jones, D.A., Round, J. & de Haan, A. (2004). Skeletal Muscle from Molecules to Movement: A textbook of Muscle Physiology for Sport, Exercise, Physiotherapy and Medicine. Churchill Livingstone, Elsevier Science Limited, London, UK.
There are, unsuprisingly, many different mechanisms for both forms of fatigue - the balance depending on intensity and duration of exercise. Peripheral mechanisms dominate for short-duration, high-intensity exercise. Loss of creatine phosphate, leading to high levels of intracellular phosphate (20 mM), seems more important than hydrogen ion formation. This arises either from exercising at rates much higher than supportable by aerobic recovery or following glycogen depletion in medium-duration exercise. Major factors driving central fatigue are a rise in temperature above 39.2 deg C and dehydration.
- I think muscle fatigue is all psycological. I have been "running" some tests and I find that when someone's conscious and sub-conscious mind are preoccupied, not only do they not show symptoms of muscle fatigue, some of them don't feel tired after the run. I think this is because when excess protons reduce the pH to 6.5 this excite the nerves near the muscle tissue and the brain consciously registers pain and so sub-consciously 1 of 2 possibilities occur, the brain turns to self-preservation mode and weakens the signals it sends to the muscles in order to decrease the amount of work done and decrease the pain. Or the brain thinks the muscles are overworked so it decreases their ability to do work. Both scenarios would result in a sense of fatigue and both would not occur if the mind were preoccupied. Just my opinion.
- Nonsense. Glycogen depletion, neural fatigue, and transient ischemia are all very real phenomena. "Muscle fatigue" refers to a variety of phenomena, all of which are well-documented. If journal research will not suffice, however, I suggest attempting a heavy weightlifting program. At a certain point, irrespective of the state of your subconscious, the muscle will quite literally buckle under a weight which it lifted a few seconds ago. Kajerm 22:12, 12 February 2007 (UTC)
This article is not terribly encyclopedic and does not reflect current scientific opinion on muscle fatigue. While it is true that lactate accumulation is not a major source of fatigue, the article makes a great deal out of it without any coherent discussion of what does cause muscle fatigue.
In the case of anaerobic exercise, muscle fatigue and muscle failure are caused almost entirely by the central nervous system; the muscles themselves play little role. This article really requires a complete rewrite, which would include:
- 1.) A comprehensive definition of muscle fatigue (that would apply for all types of exercise)
- 2.) Lay explanations of proposed mechanisms, with references
- 3.) Some practical discussion and recommendations.
This is an important topic. Unfortunately, as with most exercise-related topics, a lot of bad information and waffle is floating around. Kajerm 22:06, 12 February 2007 (UTC)
- Just did a near-total re-write, mostly based on the Lamb et al article in the references section. It's dated April, 2006 I think, so the info is pretty recent and the article itself seemed pretty dumbed down, worse than a review article. Whaddya think? Took me hours. WLU 19:33, 13 February 2007 (UTC)