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Archive for December, 2010

Putting on muscle with only light weights

December 27th, 2010

This is a topic that should stir up some controversy: a study suggesting that you don’t need to lift heavy weights to put on muscle. I blogged about this when the study first came out a few months back; I’ve since had the chance to chat with Stuart Phillips, so I wrote a Globe column with more details:

For once, scientific studies, decades of practical experience in the gym, and logic all point to the same conclusion: you need to lift reasonably heavy weights to gain strength and muscle. The American College of Sports Medicine recommends 60 to 70 per cent of your “repetition maximum” or RM (the most you can lift for a given exercise) for novices, and 80 to 100 per cent for experts.

So recently published results from McMaster University, which suggest that you can build muscle just as well – or perhaps even better – with weights as light as 30 per cent RM, have been greeted with surprise, to put it mildly.

“There are plenty of people who just don’t believe it,” admits kinesiology professor Stuart Phillips, the senior author of the paper, which appeared in the journal PLoS ONE.

The results would be welcome news for older people and weight-room neophytes, but there is a catch. The key to stimulating muscle growth, Dr. Phillips believes, isn’t linked to any particular weight or number of repetitions – it’s reaching the point of failure, where you can’t lift anymore.

Phillips has since completed a training study that actually attempts to put these finding into practice. It’ll be exciting to see what the results of that study reveal when they’re analyzed and released.

Carbohydrates vs. fat in marathons

December 22nd, 2010

These days, everyone’s interested in boosting their fat-burning abilities. After all, we have a “limitless” supply of fat, so why not rely on it during extended exercise? That’s the goal of current ideas like “train low, compete high,” where you basically practice training in a low-carb state to enhance your fat-burning abilities.

With that in mind, I quite like a nugget of info that John Hawley dug up from the archives (this 1993 paper, to be precise) about our dependence on carbohydrate during extended exercise. Researchers from George Brooks’s group at Berkeley tested runners doing a treadmill marathon in either 2:45 or 3:45, and measured what fuels they were oxidizing. The slower group used 68% carbohydrate, and the faster group used 97% (which means, as Hawley pointed out, that Geb is probably using PURE carbohydrate).

Doesn’t mean that fat-burning abilities aren’t important — but it’s worth keeping in perspective.

Sports performance and the brain on Ritalin, Wellbutrin, etc.

December 19th, 2010

Of the sessions that I attended at the Sport Nutrition Conference in Canberra last month, the one that was most unfamiliar to me was about nutrition and the brain, presented by Romain Meeusen of the Free University in Brussels. He covered a lot of ground about the various ways that the brain interacts with the periphery, but what caught my attention the most was a series of experiments using anti-depressants.

The original experiments tried giving substances like bupropion (Wellbutrin), reboxetine and Ritalin to cyclists, and didn’t see any improvement in 30min time trial performance after a 60min warm-up. BUT when they increased the temperature from 18 C to 30 C, all of the sudden these drugs produced massive improvements in performance — from 39.8 to 36.4 minutes for (I think) bupropion. Ritalin was even bigger — a seven-minute improvement.

At 18 C, most of the cyclists hit a maximum core temperature of about 39.5 C, but at 30 C they were up over 40.0 C when taking the drugs — almost to the point where the trials had to be halted for ethical reasons. As Meeusen put it, their “safety brake” didn’t work, so they were capable of pushing into the danger zone without feedback from the central nervous system. This is essentially what happened to Tom Simpson (who was taking amphetamines) on Mont Ventoux in 1967, he said.

So what does this mean? Well for starters, buproprion, which was recently taken off WADA’s banned list, should be put back on it. To Tim Noakes, this would undoubtedly sound like evidence that fatigue is governed by a “central governor.” Meeusen, as far as I can tell, doesn’t see it that way. He says “fatigue is likely to be an integrated phenomenon with complex interaction among central and peripheral factors.” Which basically means “it’s complicated.” Hard to disagree with that.

Comrades Marathon

December 16th, 2010

Just noticed that my short article about the 89-km Comrades Marathon in South Africa is now posted on the Canadian Running website. I happened to be there this year while doing some reporting for another story, and I have to say it was a pretty inspirational experience. It almost, maybe, sort of made me think I’d like to try an ultra-race someday. Maybe.

If you’re interested, Matt Leduc, the pride of Ajax, Ont., blogged about his preparations and experiences for this year’s race. However, you’ll have to look ahead to 2012: the entry deadline for the 2011 race closed on Nov. 30.

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Needless to say, Marathon Man had finished long before the 12-hour cut-off.

“Moderate” amounts of booze slow muscle recovery

December 13th, 2010

My latest column in the Globe takes on a topic of seasonal significance: alcohol and exercise. Researchers at Massey University in New Zealand have been doing some very interesting research about the links between alcohol and recovery from DOMS; and there are some other factors like glycogen replenishment and dehydration that come into play:

Earlier this year, researchers in New Zealand published a surprising study that found significant delays in muscle recovery when the subjects drank a “moderate” amount of alcohol after a strenuous workout. The findings join a little-known body of research suggesting that alcohol can sap your morning-after strength even if you’re not hung over.

The subjects in the new study did a series of leg exercises, then had 90 minutes to drink either straight orange juice or a mix of vodka and orange juice before going to bed. Over the next three days, the alcohol group didn’t report feeling any additional leg soreness compared to the OJ group – but their loss of strength in a series of tests was 1.4 to 2.8 times greater.[READ THE REST OF THE ARTICLE...]

(So that I don’t get accused of being a Scrooge, let me give away one of the article’s conclusions: truly moderate consumption, i.e. of a drink or two, shouldn’t have any effects on your recovery.)

Antioxidants block gains from endurance training

December 9th, 2010

Another study on antioxidant supplements, this one from researchers at the University of Queensland in Australia, published online in Medicine & Science in Sports & Exercise.

The study was with rats: 14 weeks of supplementation with vitamin E and another antioxidant called alpha-lipoic acid, training four times a week. The antioxidants suppressed the growth of new mitochondria (the “power plants” of your cells), which is one of the primary adaptations to endurance training. One of the new wrinkles to this study compared to previous ones is that growth of mitochondria was suppressed even in rats that weren’t training, if they took the supplements.

I’ve written several times before about this area of research. The idea is that “reactive oxygen species” (ROS) are generally bad, and antioxidants fight them. But when you exercise, the ROS you produce are the “signals” that tell your body to adapt, so if you take antioxidants, your body doesn’t realize it’s supposed to adapt and get stronger (or grow more mitochondria or whatever).

The conclusions are far from clear — for instance, this study didn’t find any reduction in the benefits of endurance training from antioxidants. But given how little evidence there is that these types of supplements actually help, the potential costs certainly seem to outweigh the benefits.

Running cuts visceral fat, and you can run through pain

December 5th, 2010

Some pretty remarkable data was recently presented at the Radiological Society of North America conference in Chicago. German researchers followed a group of 44 runners during the 4,488-kilometre TransEurope Footrace from southern Italy to northern Norway in 2009, carting along a 45-ton mobile MRI unit and a host of other diagnostic equipment:

Urine and blood samples as well as biometric data were collected daily. The runners were also randomly assigned to other exams, including electrocardiograms, during the course of the study. Twenty-two of the runners in the study underwent a whole-body MRI exam approximately every three or four days during the race, totaling 15 to 17 exams over a period of 64 days. At the close of the race, researchers began to evaluate the data to determine, among other things, stress-induced changes in the legs and feet from running. Whole-body volume, body fat, visceral fat, abdominal subcutaneous adipose tissue (SCAT), and fat and skeletal muscle of the lower extremities were measured. Advanced MRI techniques allowed the researchers to quantify muscle tissue, fat and cartilage changes.

So what did they learn from all this (other than, presumably, that anyone who enters a 4,488-kilometre is pretty fit and pretty crazy)? They highlight a few key points:

  • The runners lost a lot of fat — half of their starting amount. And most of that was lost during the first 2,000 km. (Oh, it only takes 2,000 km? How easy!) Even better, the first fat to start disappearing was the visceral fat, which surrounds the internal organs and is the really bad stuff that’s linked to heart disease. The runners lost 70 percent of their visceral fat.
  • It’s possible to run through some soft-tissue injuries without doing long-term damage. Other problems, like joint issues and stress-fractures, require rest. The press release includes this quote: “The rule that ‘if there is pain, you should stop running’ is not always correct,” Dr. Schütz said. However, they don’t give much guidance on which injuries you can run through. Presumably you need a mobile MRI unit to tell you for sure.
  • The runners also lost 7 percent of the muscle in their legs, which they call “one of the most surprising things,” but doesn’t really seem that shocking. Running that much in two months is well outside the bounds of even extreme marathon training. If I’m understanding correctly, they did about eight weeks of 550 km a week!

Anyway, this was just a conference presentation at this point. It’ll be interesting to see the full data when it’s eventually published… but it’s probably not something you should emulate.

Blogging from 5,500 metres

December 2nd, 2010

Just a heads-up that I’m heading to Nepal for most of December, leaving in… about 15 minutes. I will still be updating the blog from the road at least a couple of times a week, but sporadic Internet access means that I probably won’t be able to respond to comments and questions while I’m gone. Needless to say, I’ll catch up on any comments, debates and so on as soon as I get back

(And if you find yourself disagreeing with any I write over the next few weeks, just assume that the lack of oxygen has gotten to my brain!)