Archive for March, 2010

Whole-body compression helps recovery after strength training

March 4th, 2010

Interesting new study on compression garments in this month’s Journal of Strength and Conditioning. A team from the University of Connecticut led by William Kraemer — a big name in the field — had subjects do a heavy eight-exercise weights session, then recover either by wearing an Under Armour Recharge suit for 24 hours or by wearing their usual clothing. It was a randomized, crossover study. (I was very critical of the research Under Armour is using to promote its performance mouthpieces, so I have to give credit here: they funded what I see as a high-quality study.) The punch line:

We observed significant differences between [compression garments] and [controls] in both men and women for vitality, resting fatigue ratings, muscle soreness, ultrasound measure swelling, bench press throw, and [creatine kinase, a marker of muscle damage]. A whole body compression garment worn during the 24-hour recovery period after an intense heavy resistance training workout enhances various psychological, physiological, and a few performance markers of recovery compared with noncompressive control garment conditions.

In other words, it works!

Now, it’s worth noting that they tested a whole laundry-list of parameters, only some of which  showed improvement. The tests of reaction time, sleep quality, countermovement vertical jump and squat jump didn’t show anything. And despite a program that included biceps curl and three other upper body exercises, no changes in upper-body arm soreness were observed. Same for other areas of the body like the thighs.

But overall, it’s a positive message. It’s particularly nice to see changes not just in subjective measures (e.g. How do you feel? How sore are you?) but also in objective measures (e.g. How swollen are your muscles? How far can you throw this?) As I concluded in an earlier post, the evidence is mounting that compression really works — even if we haven’t yet mastered exactly how much is needed where. And of all the proposed uses, recovery after workout-induced muscle damage seems to be the most solid.


Why weight loss isn’t just “calories in minus calories out”

March 3rd, 2010

A few years ago, I had a long and interesting interview with Gary Taubes, the author of “Good Calories, Bad Calories”, for a piece I wrote in the Ottawa Citizen. He had a lot of interesting things to say, but the claim that stuck with me was that “calories in minus calories out” is an overly simplistic way to think about weight loss.

To think about obesity as simply consuming more calories than you expend is naïve and even meaningless [he said]. The idea that we get fat because we overeat doesn’t tell us why we overeat. If you think about it, both overeating and sedentary behaviour are behaviours, so in effect that takes the physiological disorder of excess fat accumulation and blames it on behaviour. I quote Susan Sontag in the book, who says, basically, that anytime you blame a disease on behaviour or psychology, it just tells you how little you know about the underlying mechanisms of the disease.

That’s all very well as a philosophy, but I had trouble wrapping my head around the physiology. After all, the equation of calorie deficit is so simple, how could it be wrong? An interesting piece by Tara Parker-Pope in the New York Times is what made me think about that interview. As she writes:

Numerous scientific studies show that small caloric changes have almost no long-term effect on weight. When we skip a cookie or exercise a little more, the body’s biological and behavioral adaptations kick in, significantly reducing the caloric benefits of our effort… As a recent commentary in The Journal of the American Medical Association noted, the “small changes” theory fails to take the body’s adaptive mechanisms into account.

The article does a good job of explaining this slippery idea — it’s worth a read. It also made me go back and re-read the transcript of my interview with Taubes. Here’s another excerpt that is more clear to me now than it was to me at the time: Read more…

Overtraining may cause (or result from) oxidative stress

March 1st, 2010
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“Overtraining” is one of those terms that means different things to different people. For some, it means they’re tired because they went too hard for a few workouts in a row; for others — particularly elite endurance athletes — it’s a potentially debilitating condition that can take many months to recover from. The confusion arises in part because there’s no definitive definition of the condition, or any reliable way to predict or diagnose it.

Overtraining syndrome is characterized by an unanticipated reduction in performance, despite increased or maintained training challenges.

That’s the simplest possible definition, from a new paper in the Journal of Sports Sciences by researchers from Finland. The study joins the search for physiological indicators of what’s going on and why, focusing on oxidative stress. In the normal course of events, exercise causes oxidative stress, and your body’s natural antioxidant system responds to neutralize the oxidation. The more you train, the more powerful your body’s antioxidant defenses become.

The Finnish researchers studied seven overtrained athletes, and compared them to a group of matched controls. At rest, the overtrained athletes had higher levels of oxidative stress than the controls. When they exercised to exhaustion, the antioxidant response increased in the controls, but not in the overtrained athletes — and this was still true six months later. The conclusion: overtrained athletes are no longer able to adapt to the oxidative stimulus of exercise.

Of course, this doesn’t say anything about cause and effect. But it does add weight to the argument that overtraining syndrome — whose very existence, like chronic fatigue syndrome, is often debated — really does exist as a distinct physiological state. And the researchers suggest that one of the markers of oxidative stress in the study, protein carbonyls, has potential to be used for early detection of overtraining.