IU research presented at 2014 American College of Sports Medicine meeting
May 29, 2014
FOR IMMEDIATE RELEASE
Dozens of researchers from Indiana University Bloomington, Indiana University School of Medicine and Indiana University-Purdue University Indianapolis are participating in the American College of Sports Medicine Annual Meeting in Orlando, Fla., on May 27 to 31. Below are examples of research being discussed:
Indiana University researchers say a little deception caused cyclists in their 4-kilometer time trial to up their performance even after they realized they had been tricked.
The findings support the idea that the brain plays a powerful role in how hard athletes push their bodies.
"The idea is that there's some sort of governor in your brain that regulates exercise intensity so you don't overheat, or run out of gas, so to speak," said Ren-Jay Shei, a doctoral student in the IU School of Public Health-Bloomington. "In this case, the governor was reset to a higher upper limit, allowing for improved performance."
For the study, 14 trained, competitive male cyclists participated in four time trials. For each session, they rode cycle ergometers, which are stationary bikes that measure such variables as speed and power output and display the readings on computer monitors on the handlebars.
The first time trial was designed to familiarize the cyclists with the procedures. The second was considered the baseline session. In the third and fourth, two avatars and their corresponding stats appeared side by side on the computer monitors. In the session involving deception, the stats for the avatar on the right were programmed to be 102 percent of the baseline performance of the cyclist, yet the cyclist was told the stats were based on his actual baseline results.
Not only did most of the cyclists improve during the deception round, but the group improved by an average of 2.1 percent over baseline even when they knew they had been tricked.
"This helps us understand how the body protects itself during exercise," Shei said.
Shei is discussing the findings during the behavioral aspects of sport session today. Co-authors include Robert F. Chapman, John S. Raglin and Timothy D. Mickleborough, all in the Department of Kinesiology in the IU School of Public Health-Bloomington; and Kevin G. Thompson, Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia.
Indiana University researchers put male rats to the test to determine the role amphetamines play when used in conjunction with exercise.
When people or animals exercise in the heat, exhaustion is a safety gauge telling the body it is time to stop. Exhaustion occurs when the body's core temperature reaches a potentially dangerous point. The use of amphetamines is banned in many sports because they increase time to exhaustion.
What they found: Amphetamines can delay exhaustion during exercise in the heat by increasing the temperature at which it occurs. This potentially ergogenic effect, however, comes at the risk of suffering from exertional heat stroke.
Daniel E. Rusyniak, M.D., associate professor of emergency medicine at the IU School of Medicine, and colleagues in the Department of Emergency Medicine and the Department of Health and Rehabilitation Sciences, hypothesized that amphetamines increase the time to exhaustion by allowing the core temperature to climb higher before exhaustion occurs. Rusyniak and his team also wanted to determine whether oxygen consumption was affected and whether it played a role in the threshold for exhaustion.
The rats were familiarized with running on the treadmill for several days before the experiment. On that day, with the room at 89.6 degrees Fahrenheit, a control group of rats was given saline injections, while two other groups were given amphetamine injections of either 1 milligram or 2 milligrams per kilogram of body weight.
As predicted, the animals receiving amphetamine had significantly higher core temperatures when they reached exhaustion. What was not predicted is that animals receiving the higher dose of the amphetamine achieved this critical temperature faster so that their time to exhaustion was not increased.
The researchers also determined that muscles consumed oxygen at a higher rate in the group receiving the larger amphetamine dosage, but there was no evidence that the efficiency or "economy" of the oxygen use was improved.
"The benefit of amphetamine use was probably not related to anything other than raising the temperature at which exhaustion occurs, which from a medical safety standpoint is not a benefit at all," Rusyniak said.
"Amphetamine increases Vo2max and time to exhaustion at the expense of body temperature and economy" was discussed Wednesday during the heat stress session.
A pilot study by Indiana University researchers found that whole-body vibration exercise may reduce pain symptoms and improve aspects of quality of life in individuals diagnosed with fibromyalgia.
"Our findings are promising, but it is not entirely clear whether these improvements were the result of added vibration or just the effects of being more active," said lead author Tony Kaleth, associate professor in the School of Physical Education and Tourism Management at Indiana University-Purdue University Indianapolis.
Regular exercise participation is one of the best known therapies for patients with fibromyalgia, a disorder characterized by widespread musculoskeletal pain and fatigue. Many patients, however, are averse to participating over fears of pain that may be associated with increased physical activity. As a result, said Kaleth, many patients continue to spiral downward, further exacerbating a sedentary lifestyle that often leads to a worsening of symptoms.
"Over time, this can lead to additional weight gain, as well as accompanying chronic health conditions associated with obesity, such as high blood pressure and type 2 diabetes," he said.
Whole-body vibration exercise involves standing, sitting or lying on a machine with a vibrating platform that causes muscles to contract and relax as the machine vibrates. The machines primarily are used by researchers but have begun appearing in fitness centers and are sold commercially.
"Vibration training is increasingly being studied in clinical populations as a potential therapeutic mode of exercise training," Kaleth said. "Although the results are largely equivocal and in need of further study, studies have reported improvements in strength, muscle spasticity and pain in select populations."
Fibromyalgia, which has no cure, is primarily diagnosed in women and may also involve difficulties with sleep, memory and mood. The disorder affects an estimated 1 to 3 percent of the population.
Kaleth is discussing "Effects of whole-body vibration exercise on physical function and pain severity in patients with fibromyalgia" during the clinical populations session today. Co-authors include Sandi DeSabatine, School of Physical Education and Tourism Management; and Dennis C. Ang, IU School of Medicine.