Tired in the head

Many Canadians now spend their workdays sitting in front of a computer – a cushy gig, you might think, that would leave them fresh for a nice hard run after work. But the reality can be very different, and new research from Bangor University in Wales sheds some light on why. The researchers had 16 subjects ride a stationary bicycle to exhaustion, after performing either a mentally challenging 90-minute task or a very simple 90-minute task. The mentally fatigued subjects had to stop biking 15 percent earlier than the controls, even though their breathing and heart function weren’t any different.

There are two possible explanations, according to lead researcher Samuele Marcora: either mental fatigue lowers the brain’s inhibition to quitting, or it affects dopamine levels, which in turn affect motivation. Hard mental effort activates the anterior cingulated cortex of the brain, Dr. Marcora notes, which experiments with rats suggest is associated with perception of effort. None of this means that we shouldn’t train after work – it just confirms the impression that a tough day can affect how the run feels. And if you’re getting ready for a big race, it’s a good excuse to put your feet up and turn your brain off the day before, rather than catching up with all your chores and errands.

Sprint supplement

There may be hundreds of runners in front of you and hundreds more behind you at a typical road race. But somehow, it’s the guy or gal who sprints past you right before the finish line – or the runner you outsprint – who sticks in your mind. Now researchers at the Catholic University of Leuven in Belgium are reporting a pill that can enhance your sprint finish even at the end of a two-hour race. The substance is a legal supplement called beta-alanine, and it acts to buffer the rising levels of acidity that maximal effort causes in your muscle cells. The benefits of beta-alanine for bouts of exercise lasting one to two minutes have been known for a long time, but the application to endurance events is new.

In a double-blind study published in the April issue of Medicine & Science in Sports & Exercise, cyclists took part in a 110-minute simulated race, then did a 10-minute time trial followed by a 30-second sprint. Those who had received eight weeks of beta-alanine, starting at 2 grams a day and gradually increasing to 4 grams a day, produced 11.4 per cent more power in their final sprint. Of course, whether you get the same sense of satisfaction from a pill-powered sprint to the finish is another question entirely.

Runners are dense

We reported in our April issue on a study that showed cyclists were more likely than the general population to have low spinal bone density, and noted that similar studies of runners have produced conflicting results. A new study in the Journal of Strength and Conditioning Research offers some welcome clarity. Pamela Hinton and her colleagues at the University of Missouri tested three groups: runners, cyclists and people who exercised by lifting weights. The runners and resistance trainers came out ahead of the cyclists – which, as Dr. Hinton noted, was expected.

What previous studies have failed to do, though, is take body size and composition into account. Weightlifters tend to be bigger than runners, so they have correspondingly bigger bones – and that can make runners look bad in comparative studies. When the researchers controlled for body size, a new pattern emerged. “The results of the study confirm that both resistance training and high-impact endurance activities increase bone mineral density,” Dr. Hinton explained. “However, high-impact sports, like running, appear to have a greater beneficial effect.” Pound for pound, in other words, all that pounding pays off.

Ergogenic tunes

If you listen to music when you run, you may think picking the right tunes is an art, but researcher Costas Karageorghis, a sports psychologist at Britain’s Brunel University, has made it a science. In the latest issue of the Journal of Sport & Exercise Psychology, Dr. Karageorghis and his colleagues report a study on the endurance-enhancing effects of motivational music – the latest in a long series of investigations by this research group. In an earlier study, Dr. Karageorghis reported that songs with the right characteristics could increase exercise performance by up to 20 per cent, by diverting attention from discomfort and fatigue, and by synchronizing movements to the rhythm.

If you’re not sure what the best running music is, there are even services like Australian runner and composer Gary Blake’s Run2Rhythm (www.run2r.com) that compose music specifically for running. A “half-marathon mix,” for example, begins with a steady drum-and-bass beat, and gradually increases its pace, reaching maximum motivational power during the hardest parts of the race. More generally, Dr. Karageorghis says, both lyrics and beat should be carefully tailored to duration and intensity of exercise, as well as to personal taste. He offers the following suggestions:

Exercise intensity Rock Pop Soul/R&B Classical
55% Max HR The Best – Tina Turner Lifted – Lighthouse Family Back to Life – Soul II Soul Spring from “The Four Seasons” – Vivaldi
65% Max HR Keep on Running – The Spencer Davis Group Don’t Stop Til You Get Enough – Michael Jackson I Will Survive – Gloria Gaynor Radetzky March – Johann Strauss
75% Max HR Born to be Wild – Steppenwolf Movin’ Too Fast – Artful Dodger & Romina Johnson I Feel Good – James Brown Troika – Prokofiev
85% Max HR The Heat Is On – Glenn Frey Reach – S Club 7 Everybody Needs Somebody to Love – The Blues Brothers William Tell Overture – Rossini

(source: Dr. Costas Karageorghis, Brunel University)

Pacing in the heat

In the heat of summer, it’s common to see runners fading badly at the end of a race. Australian researchers decided to test pacing ability in hot conditions by having 11 cyclists do a series of 20K time trials in 33 C heat. In the first trial, they were allowed to pace themselves however they wanted. Subsequent trials involved starting the first 2.5K at either 10 per cent slower than the first trial, 10 per cent faster, or the same pace. In the end, the results from all groups were indistinguishable – the final 20K times were the same, as were physiological measurements like rectal temperature and skin temperature. This is a surprising result, as earlier studies had suggested that a slower start would lead to a faster overall time – and, given the small number of subjects, it shouldn’t be given too much weight. Nonetheless, it suggests that we do have some margin for error as we settle in to an appropriate pace on a hot day.

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