Athletes' Feats: Case of Conditioning or Genetics?
March 2, 2010 –The world's greatest athletes just ended their quest for Olympic gold during the Winter Games in Vancouver -- many of them accomplishing amazing physical acts during competition. World records fell in speed skating, figure skaters landed superior quadruple and triple jumps and a cross-country skier from Slovenia managed to win bronze despite competing with four broken ribs. J.P. Hyatt, assistant professor of human science in the School of Nursing & Health Studies, is an expert in how muscles adapt to exercise. He says there is more to Olympic feats than just natural-born talent or rigorous training. Hyatt talks about the science behind muscle fibers, why humans aren't becoming faster -- and why records continue to fall regardless.
Q. What does it take to perform at the Olympic level?
A. It's a combination of three things. One is a genetic predisposition. Two is training, which can be subcategorized into frequency, intensity and duration of training. Lastly, there are psychological factors: how good an athlete is, for example, at focusing on his or her goal or brushing off defeat to focus on the next event. You need the right balance of these factors to compete at an elite level.
Q. Could you elaborate on the role of genetic predispositions?
A. If you're genetically predisposed to having a larger lung capacity, then that would allow you to have a more efficient exchange of oxygen and carbon dioxide. So, that could be one of the genetic advantages an athlete could have versus someone with a small lung capacity.
If you're an Olympian cross-country skier, you probably have genetic muscle advantages for that sport. It's the same thing with marathon running -- you can't take an average Joe and expect him to perform at an elite level. It comes down to the percent distribution between the fiber types in working muscles: fast twitch or slow twitch.
Q. Can you explain the difference?
A. All of our muscles are composed of a mix of fast- and slow-twitch muscle cells. The way I like to look at it is a predominantly slow twitch muscle is the tortoise whereas the fast twitch muscle is the hare. The fast-twitch cells are adept at speed and power events, so sprinters will have a higher population of those fast-twitch cells. Endurance athletes will have a higher population of slow-twitch muscle cells.
Most of us have a 50/50 split between fast and slow twitch. Athletes successful in aerobic competitions, such as marathons, might have a 60/40 or 70/30 split in favor of slow twitch instead.
Q. How do muscle fibers affect athletes' success in their chosen sport?
A. You don't pick the sport; the sport picks you. You'll have a tendency to gravitate toward sports that are easy for you. They're easy based on your genetic makeup, which can affect your training.
Let's say you have a kid with more fast-twitch muscle cells -- he will likely gravitate toward sprinting because he's made for that. He could train as hard as he wanted for long-distance running, but he'll never likely never perform at an elite level comparable to the Olympics.
Q. Records seem to fall at every Olympics. Are humans becoming physiologically superior over time?
A. I wanted to ask the same question -- are we getting faster? To do this, I compared winning times from the mid-1980s through 2004 for final heat of the Olympics 100-meter sprint for men and women, and found a flat line. The times really have not improved in a statistically significant way in recent decades.
Q. And yet records are still broken. What accounts for that if physiological advances do not?
A. One factor is training improvements; training has become much more sport-specific. Eating and diet also play big roles, as does equipment. It's not just what you wear, but where you compete. Tracks used to be hard-packed dirt, but now they're rubberized asphalt. Or take bobsleds in the 1930s versus the ones used now. There's no comparison in the technology. Pole vault poles are no longer bamboo. Cycling shoes are clipless. That's why we've seen a change in performance.
Q. After training for years, do athletes enjoy permanent physical benefits from training?
A. Literature says that any training advantages will return back to normal levels within about six months. So, if your only activity is sitting in an office, your body will adapt to that.
That's why we need to keep challenging ourselves. By working out, lifting weights or running, you change the level of homeostasis, and you'll adapt to that new regimen.
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