If you head out of town on your bike or go for a relaxing cycle in the countryside, be sure not pedaling too fast. That's the advice of a group of physiologists have found that people burn more energy than necessary when pedaling furiously, except the elite cyclists. The researchers came to this conclusion by developing a new equation to describe the performance of cycling, which they say should help people in better shape
Many bikes already contain a device designed to prevent overpedaling :. Gears. Muscles contract work best when neither too fast nor too slow. To go fast, you will use less energy in a higher gear, even if you have to push harder on the pedals, because your leg muscles are much more effective at lower rate of contraction. Similarly, the gear is better to go up because they prevent you to pedal more slowly than you should.
To know exactly how the pedaling rate affects energy consumption, physiologist Federico Formenti of Oxford University in the UK and colleagues studied how 10 men of different ages and fitness levels physical performed on an exercise bike in a laboratory at the University of Auckland in New Zealand (where previously was located Formenti). Each cyclist pedaled faster and faster against the different loads while a mask monitored the amount of oxygen consumed-that a measure of metabolic rate.
Formenti and colleagues reported 0 such measures (16 per participant), and compare them with oxygen consumption rate predicted by an equation recommended by the American College of Sports Medicine (ACSM). This equation involves only two variables the mass of a cyclist and "work rate" equal to the exercise bike of the resistance force multiplied by the distance the bike would go if it was not attached to the ground
[the researchers found they could get a better match to the observed values of oxygen consumption by changing the equation to add a third variable: the pedaling rate, they report today in the reports physiological. estimates of the oxygen absorption ACSM equation quite well most of the time, Formenti said, because the formula for work rate already includes pedaling rate. But, he noted, the equation fails to capture the relative number imposed by the resistive force and pedaling speed. in fact, he and his colleagues found that high pedaling rate and low employment rates, test participants used up more of their energy simply spinning their legs. "The physiological response of muscles to exercise is very different if they contract slowly against a high resistance compared to contract them quickly against little resistance," he said.
The oxygen consumption during exercise is often used to measure capacity. Formenti said the new equation should improve fitness monitoring in gyms that are not equipped to analyze the breath directly. He warned that the results of his group to be confirmed by larger studies of exercisers, including women, but notes that data from previous studies totaling 50 riders gave a good match for the values of consumption oxygen new equations.
Ernst Hansen, a sports scientist at the University of Aalborg in Denmark, who was not involved in the research, agrees that the equations describing the performance of the bike should include the rate pedaling. But he argues that the new equation is relatively simplistic, because it ignores individual differences in the effectiveness of muscle fibers and choice pedaling rate. Formenti recognizes that such changes are beyond the scope of his study group, but said they could explain why the cycle of effective elite cyclists, though they pedal very quickly.
As to why the so-called recreational cyclists are better pedal slower, the jury seems to be out. Formenti and colleagues believe that this is due to what they call "inner work" cyclists consume energy as they move up and down legs, as distinct from the "external work" (work rate) which propel the bicycle forward. The researchers measured the internal work during their pedaling motion tracking tests with infrared beams bounced off the body of cyclists. They found that the internal work jumped 10 times when a cyclist has increased its rate from 50 to 110 revolutions per minute pedaling, whatever external work done. Therefore, they say, a bicycle average man size at the higher rate would use about 60% of its energy just to run his legs.
Others, however, disagree with this interpretation. Steven Kautz, a biomedical engineer at the Medical University of South Carolina in Charleston, agrees that the estimates of oxygen consumption should consider the speed of pedaling, but said the reason has nothing to do with work internal. The internal and external work are "not independent quantities of additives," he said, because the first to some extent it generates. Instead, it maintains, the effect of pedaling rate is probably due to the subtleties of dynamic muscles.
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