[知識] Muscle lab: Bulk up with the science of bodybuilding

看板FITNESS作者Berlin (自古名士多風流)時間14年前 (2010/08/25 02:26)推噓5(5推 0噓 16→)

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15:31 18 August 2010 by Jessica Hamzelou Looking to beef up? As research sheds new light on how our muscles work, it may be time to scrap old bodybuilding advice. New Scientist brings you top tips for the budding Mr Universe. What is the best way to pump iron? Standard advice for gym bunnies is to lift as much weight as you can in a training session. But Stuart Phillips and his team at McMaster University in Hamilton, Ontario, Canada, reckon this might not be the best way to build muscle. Instead, they suggest that slow and steady wins the race. In Phillips's study, men in their early 20s lifted weights with their legs over various periods at 30 and 90 per cent of the maximum weight they could lift. Phillips analysed biopsies from the leg muscles before and after each training session. He found that the production of new muscle proteins was greatest when the men were lifting the relatively light weights – at 30 per cent of their maximum – until they were fatigued, and couldn't lift any more. The idea that you should lift progressively heavier weights to bulk up is "completely false", says Phillips. Instead, the best way to build muscle is to lift more manageable weights until you tire out, he says. Is it easier to rebuild lost muscle than start from scratch? The phenomenon of "muscle memory" is a handy one for muscle buffs who take extended breaks between workouts. The idea is that once a person has acquired a certain level of strength for the first time, they will find it easier to reach that point again, even if they allow their muscles to waste away in the meantime. Kristian Gundersen and his colleagues at the University of Oslo in Norway reckon the explanation lies in the fact that muscle undergoes permanent changes during training. To investigate, Gundersen's team cut the synergist, or "helper", leg muscles in one leg in mice, thereby increasing the amount of work for the remaining muscle. After two weeks, the group found that the number of nuclei in the fibres of the remaining muscle had increased by 37 per cent. This bulked-up muscle was then left to waste by cutting off its nerve supply. However, three months later – equivalent to around 10 human years – the increased number of nuclei remained within the muscle fibres. Because the nuclei of muscle fibres are key to the production of new muscle protein, Gundersen thinks that after a bout of training, the potential to grow muscle sticks with you for life. So no matter how much time has passed since you were in the peak of muscular fitness, it should be easier to achieve the second time around. What about steroids? Anabolic steroids are thought to work by increasing the number of muscle cell nuclei. "If those effects are also permanent, the effects of one-time doping could last forever," says Gundersen. "We may need to reconsider how long the exclusion period should be for an athlete caught taking steroids." What's that burning feeling a day or two after a workout? The ache you feel a couple of days after particularly intensive exercise is known as "delayed onset muscle soreness". It is thought to be caused by the lengthening and subsequent damage of muscle fibres during strenuous stretches. Damaged muscle cells can die off, causing inflammation and pain. Muscle builders take note: overly arduous workouts could work your muscles into oblivion. What's the ideal diet for a bodybuilder? It is important to get enough protein in your diet, from foods such as red meat and eggs, as amino acids are essential for making new muscle proteins. In a 2004 paper, Charles Lambert, then at the University of Arkansas in Little Rock, and colleagues recommended that protein make up 25 to 30 per cent of a bodybuilder's diet. During exercise, most of the energy for muscle work comes from carbohydrates that have been broken down into glucose and converted to glycogen. Lambert's team reckoned carbs should make up around 55 to 60 per cent of a bodybuilder's energy intake. Before a photo shoot, some male models are known to go to drastic lengths to look their most buff. A pre-shoot drinking binge dehydrates the skin, so it is pulled taut over the muscles to accentuate them. A healthier way to look your best would be to cut fat intake, says Phillips. But cutting out too much fat could be a mistake. Lambert thinks fat should make up around 15 to 20 per cent of total energy intake. Reducing fat in the diet is known to reduce circulating levels of testosterone, which is thought to boost muscle mass and limb strength. Journal references: Phillips, PLoS One, DOI: 10.1371/journal.pone.0012033; Gundersen, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0913935107; Lambert, Journal of the American Geriatrics Society, DOI: 10.1111/j.1532-5415.2008.01927.x 出處： http://0rz.tw/aih3d 很想上色但我不會= = 反正每段就看開頭跟結尾就差不多懂意思 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 59.115.178.85

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08/25 02:41, , 1^F

08/25 02:41, 1^F

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