With the Olympics over and the NBA and NHL not yet into playoff mode, the NFL knows its fans need a shot of football in late winter. To prepare us (and the team general managers and coaches) for the NFL Draft in early May, 300 of the best college football players visited Lucas Oil Stadium in Indianapolis last week for the annual NFL Scouting Combine.
While there are specific drills that the players go through for each position, it is the six workout drills, testing strength, agility, jumping and speed, that generate the most TV coverage and conversation. However, sport science researchers keep putting out study after study that shows that not only are the six tests redundant but that they also have little correlation to actual NFL performance, making them poor predictors for success
Turning up the heat might be the best thing for athletes competing in cool weather, according to a new study by human physiology researchers at the University of Oregon. Published in the October issue of the Journal of Applied Physiology, the paper examined the impact of heat acclimation to improve athletic performance in hot and cool environments.
Researchers conducted exercise tests on 12 highly trained cyclists -- 10 males and two females -- before and after a 10-day heat acclimation program. Participants underwent physiological and performance tests under both hot and cool conditions. A separate control group of eight highly trained cyclists underwent testing and followed the same exercise regime in a cool environment.
The data concluded that heat acclimation exposure provided considerable ergogenic benefits in cool conditions, in addition to the expected performance benefits in the hot environment. The study is the first to evaluate impacts of heat acclimation on aerobic performance in cool conditions.
"Our findings could have significant impacts in the competitive sports world," said Santiago Lorenzo, a researcher who performed the work as part of his dissertation at the University of Oregon. He is now completing post-doctoral training in the Institute for Exercise and Environmental Medicine (University of Texas Southwestern Medical Center) at Texas Health Presbyterian Hospital Dallas.
The study found performance increases of approximately 7 percent after 10 heat acclimation exposures. "In terms of competitive cycling, 7 percent is a really big increase and could mean that cyclists could use this approach to improve their performance in cooler weather conditions," said Lorenzo. However, the heat exposures must be in addition to the athletes' normal training regimen.
Heat acclimation improves the body's ability to control body temperature, improves sweating and increases blood flow through the skin, and expands blood volume allowing the heart to pump to more blood to muscles, organs and the skin as needed.
Another approach using the environment to improve exercise performance is a "live high/train low" regimen, which means residing at a high altitude and training at a low altitude. Many athletes worldwide now use this approach. According to Lorenzo, "heat acclimation is more practical, easier to apply and may yield more robust physiological adaptations."
(Photo credit: SlowTwitch.com)
The study was conducted in the Evonuk Environmental Physiology Core lab at the UO department of human physiology. The climatic chamber was set at 38 degrees Celsius (100 degrees Fahrenheit) for heat testing and 13 degrees Celsius (55 degrees Fahrenheit) for cool conditions with consistent humidity (30 percent relative humidity) for the cyclists' exercise tests.
According to Christopher Minson, co-director of the Evonuk lab, head of the UO human physiology department and study co-author, researchers also concluded that the heat may produce changes in the exercising muscle, including enzymatic changes that could improve the amount of work done by the muscle, but he says future research will have to examine it further.
"A next step is to determine whether heat acclimation improves performance in a competitive or real-world setting," said Minson.
He also notes possible implications for people with cardiac or other limitations such as paralysis that don't allow for the full cardiovascular benefits of exercise. If heat can be added, "it's conceivable that they would gain further cardiovascular benefits than exercise alone in a cool environment. These are exciting questions that deserve further study," said Minson.
Source: University of Oregon and S. Lorenzo, C. T. Minson. Heat Acclimation Improves Cutaneous Vascular Function and Sweating in Trained Cyclists. Journal of Applied Physiology, 2010; DOI: 10.1152/japplphysiol.00725.2010
Significant differences in knee alignment and muscle activation exist between men and women while kicking a soccer ball, according to a study published this month in the Journal of Bone and Joint.
Data reveal that males activate certain hip and leg muscles more than females during the motion of the instep and side-foot kicks -- the most common soccer kicks -- which may help explain why female players are more than twice as likely as males to sustain an Anterior Cruciate Ligament (ACL) injury.
Soccer is one of the fastest-growing sports in the United States with approximately 20 million registered players and an annual participation increase of more than 20 percent , according to statistics from the National Collegiate Athletic Association (NCAA) . Women also are playing this sport on more competitive levels. Prior research shows that females are more prone to non-contact ACL injuries than males and though many theories exist, a direct cause for the disparity is unknown.
"By analyzing the detailed motion of a soccer kick in progress, our goal was to home in on some of the differences between the sexes and how they may relate to injury risk," said orthopaedic surgeon Robert H. Brophy, MD, study author and assistant professor of orthopedics, Washington University School of Medicine in St. Louis. "This study offers more information to help us better understand the differences between male and female athletes, particularly soccer players."
Dr. Brophy and his colleagues from the Motion Analysis Laboratory and Sports Medicine Service at the Hospital for Special Surgery in New York used 3-D video-based motion analysis and electromyography to examine the differences between 13 male and 12 female college soccer players during the action of kicking a soccer ball.
Using eight to 10 video cameras, 21 retroreflective markers and 16 electrodes simultaneously, researchers measured the activation of seven muscles (iliacus, gluteus maximus, gluteus medius, vastus lateralis, vastus medialis, hamstrings and gastrocnemius) in both the kicking and supporting legs; as well as two additional muscles (hip adductors and tibialis anterior) in the kicking leg only. Five instep and five side-foot kicks were recorded for each player. Muscle activation was recorded as a percentage of maximum voluntary isometric contraction.
They found that male players activate the hip flexors (inside of the hip) in their kicking leg and the hip abductors (outside of the hip) in their supporting leg more than females.
* In the kicking leg, men generated almost four times as much hip flexor activation as females (123 percent in males compared to 34 percent in females).
* In the supporting leg, males generated more than twice as much gluteus medius activation (124 percent in males compared with 55 percent in females) and vastus medialis activation (139 percent in males compared with 69 percent in females).
"Activation of the hip abductors may help protect players against ACL injury," said Dr. Brophy, a former collegiate and professional soccer player and past head team physician for the former St. Louis Athletica professional women's soccer club. "Since females have less activation of the hip abductors, their hips tend to collapse into adduction during the kick, which can increase the load on the knee joint in the supporting leg, and potentially put it at greater risk for injury."
Brophy said that although the study does not establish a direct cause-and-effect relationship between muscle activation and knee alignment and ACL injuries, the finding "moves us toward better understanding of what may contribute to differences in injury risk between the sexes and what steps we might take to offset this increased risk in females."
The current research in the area of ACL injury prevention has shown some promise. For example, in 2008, the Centers for Disease Control and Prevention published a study that found a new training program called the Prevent Injury and Enhance Performance (PEP) program, was effective in reducing ACL injuries in female soccer players. Developed by the Santa Monica Orthopedic and Sports Medicine Research Foundation and supported by the American Academy of Orthopaedic Surgeons (AAOS) among other medical and athletic associations, PEP is an alternative warm-up regimen that focuses on stretching, strengthening and improving balance and movements and can be conducted during regular practice time and without special equipment.
"Programs focusing on strengthening and recruiting muscles around the hip may be an important part of programs designed to reduce a female athletes' risk of ACL injury," said Dr. Brophy. "Coaches and trainers at all levels, from grade school through professional, should consider using strategies that demonstrate potential to prevent these injuries."
He said that additional research is warranted to investigate how the differences in hip muscle activation and alignment between the sexes may relate to differences in the risk of lower extremity injury among athletes in soccer and other sports.
Anterior cruciate ligament injuries are a common and debilitating problem, especially for female athletes. A new study from UC Davis shows that changes in training can reduce shear forces on knee joints and could help cut the risk of developing ACL tears.
"We focused on an easy intervention, and we were amazed that we could reduce shear load in 100 percent of the volunteers," said David Hawkins, professor of neurobiology, physiology and behavior at UC Davis. Hawkins conducted the study at the UC Davis Human Performance Laboratory with graduate student Casey Myers.
The anterior cruciate ligament lies in the middle of the knee and provides stability to the joint. Most ACL injuries do not involve a collision between players or a noticeably bad landing, said Sandy Simpson, UC Davis women's basketball coach.
"It almost always happens coming down from a rebound, catching a pass or on a jump-stop lay-up," Simpson said. "It doesn't have to be a big jump."
Hawkins and Myers worked with 14 female basketball players from UC Davis and local high schools. They fitted them with instruments and used digital cameras to measure their movements and muscle activity, and calculated the forces acting on their knee joints as they practiced a jump-stop movement, similar to a basketball drill.
First, they recorded the athletes making their normal movement. Then they instructed them in a modified technique: Jumping higher to land more steeply; landing on their toes; and bending their knees more deeply before taking off again.
After learning the new technique, all 14 volunteers were able to reduce the force passed up to the knee joint through the leg bone (the tibial shear force) by an average of 56 percent. At the same time, the athletes in the study actually jumped an inch higher than before, without losing speed.
Hawkins recommends warm-ups that exercise the knee and focusing on landing on the toes and balls of the feet. The study does not definitively prove that these techniques will reduce ACL injuries, Hawkins said: that would require a full clinical trial and follow-up. But the anecdotal evidence suggests that high tibial shear forces are associated with blown knees.
Hawkins and Myers shared their findings with Simpson and other UC Davis women's basketball and soccer coaches, as well as with local youth soccer coaches. The research was published online Aug. 3 in the Journal of Biomechanics.
Simpson said that the team had tried implementing some changes during last year's preseason, but had found it difficult to continue the focus once the full regular season began. In live play, athletes quickly slip back to learned habits and "muscle memory" takes over, he noted. More intensive off-court training and practice would be needed to change those habits, he said.
"We will be talking about this again this season," Simpson said. Implementing the techniques in youth leagues, while children are still learning how to move, might have the most impact, he said.
New research suggests that athletes and footballers may want to limit the time they spend training at altitude to improve their performance. An Oxford University study has found that people with a rare condition that mimics being at high altitude for long periods show metabolic differences that actually reduce their endurance and physical performance.
The study is published in the journal PNAS and was funded by the British Heart Foundation and the Wellcome Trust.
Athletes from many endurance disciplines use altitude training as part of their yearly training programme. England footballers, as with many of the teams in the World Cup, spent time at altitude acclimatising for the competition in South Africa.
The body reacts to the low levels of oxygen at high altitude, first of all by breathing harder and the heart pumping more blood, but then through producing more red blood cells and increasing the density of blood vessels in the body's muscles. All of this serves to get more oxygen and fuel to the muscles.
However, an extended stay at altitude can bring a loss of the muscle's ability to use oxygen to carry out work. The number of mitochondria, the oxygen-using powerhouses of the cell, falls with a prolonged stay at high altitude.
"It is the higher capacity to deliver fuel to muscles that athletes are interested in," explains lead author Dr Federico Formenti of the Department of Physiology, Anatomy and Genetics at the University of Oxford. 'However, it's not clear how long they should train at altitude or how high up they need to be to get the optimal benefits."
A protein called hypoxia-inducible factor (HIF) is central to the body's response to high altitude. It is stimulated by low levels of oxygen and sets many of these processes in train.
The Oxford University researchers set out to study the metabolism of people with a rare genetic change that leads to continually high levels of HIF, even when levels of oxygen are normal. The increased levels of HIF mean that the condition -- called Chuvash polycythemia or CP -- is a good model for changes that occur in people who stay at high altitude for long periods. CP can also offer insight into the fundamental processes where oxygen supply in the body is limited, such as in lung disease, heart disease, vascular disease and cancer.
Only around 20 people in the UK are known to have this mild condition. It is typically only diagnosed when a standard blood test shows increased numbers of red blood cells and further tests are done.
The team compared the performance of five people with CP with five matched controls. In an exercise bike test, in which study participants were asked to keep a constant pedal rate against a steadily increasing resistance, those with CP had to stop exercising earlier. The maximum work rate they achieved for their weight was 30% less than controls.
Studies of metabolites present in calf muscles under light exercise also indicated that CP patients experienced greater fatigue. Finally, there were differences in expression of metabolic genes in the CP patients' muscles. This could suggest their metabolism makes less efficient use of the fuel available and may explain their reduced exercise capacity.
"We found that the metabolism of CP patients is different and leads to poorer physical performance and endurance," says Dr Formenti. "Although this is a small study -- necessarily so because of there are so few people with the condition -- the results are striking. The differences seen in those with Chuvash polycythemia were large, and five patients were more than enough to see this effect."
"With the help of our volunteers with Chuvash polycythemia, we now understand these fundamental processes better. This understanding should eventually lead to better medical care in the many conditions where oxygen supply in the body is limited, such as heart disease and cancer,"
says principal investigator Professor Peter Robbins of Oxford University.
In the record books, the swiftest sprinters tend to be of West African ancestry and the faster swimmers tend to be white. A study of the winning times by elite athletes over the past 100 years reveals two distinct trends: not only are these athletes getting faster over time, but there is a clear divide between racers in terms of body type and race.
Last year, a Duke University engineer explained the first trend -- athletes are getting faster because they are getting bigger. Adrian Bejan, professor of engineering at Duke's Pratt School of Engineering, now believes he can explain the second trend.
In a paper published online in the International Journal of Design and Nature and Ecodynamics, Bejan, and co-authors Edward Jones, a Ph.D. candidate at Cornell University currently teaching at Howard University, and Duke graduate Jordan Charles, argue that the answer lies in athletes' centers of gravity. That center tends to be located higher on the body of blacks than whites. The researchers believe that these differences are not racial, but rather biological.
"There is a whole body of evidence showing that there are distinct differences in body types among blacks and whites," said Jones, who specializes in adolescent obesity, nutrition and anthropometry, the study of body composition. "These are real patterns being described here -- whether the fastest sprinters are Jamaican, African or Canadian -- most of them can be traced back generally to Western Africa."
Swimmers, Jones said, tend to come from Europe, and therefore tend to be white. He also pointed out that there are cultural factors at play as well, such as a lack of access to swimming pools to those of lower socioeconomic status.
It all comes down to body makeup, not race, Jones and Bejan said.
"Blacks tend to have longer limbs with smaller circumferences, meaning that their centers of gravity are higher compared to whites of the same height," Bejan said. "Asians and whites tend to have longer torsos, so their centers of gravity are lower."
Jordan Charles (L) and Adrian Bejan
Duke University
Bejan and Jones cite past studies of the human body which found that on average, the center of gravity is about three percent higher in blacks than whites. Using this difference in body types, the researchers calculated that black sprinters are 1.5 percent faster than whites, while whites have the same advantage over blacks in the water. The difference might seem small, Bejan said, but not when considering that world records in sprinting and swimming are typically broken by fractions of seconds.
The center of gravity for an Asian is even more advantageous to swimming than for a white, but because they tend not to be as tall, they are not setting records, Bejan said.
"Locomotion is essentially a continual process of falling forward," Bejan said. "Body mass falls forward, then rises again. Mass that falls from a higher altitude falls faster. In running, the altitude is set by the location of the center of gravity. For the fastest swimmers, longer torsos allow the body to fall forward farther, riding the larger and faster wave."
The researchers said this evolution of body types and increased speeds can be predicted by the constructal theory, a theory of natural design developed by Bejan that explains such diverse phenomena as river basin formation and basis of animal locomotion (www.constructal.org).
Jones said that the differences in body densities between blacks and whites are well-documented, which helps explain other health differences, such as the observation that black women have a lower incidence of osteoporosis than white women because of the increased density of their bones.
Jones notes that cultural issues can play a role in which form of athletic competition someone chooses, and therefore might excel in.
"When I grew up in South Carolina, we were discouraged from swimming," said Jones, who is black. "There wasn't nearly as much encouragement for us as young people to swim as there was for playing football or basketball. With the right encouragement, this doesn't always have to be the case -- just look at the Williams sisters in tennis or Tiger Woods in golf."
The positive effects of exercise while growing up seem to last longer than previously believed. New findings suggest that physical activity when young increases bone density and size, which may mean a reduced risk of osteoporosis later in life, reveals a thesis from the Sahlgrenska Academy at the University of Gothenburg, Sweden.
For the thesis, around 3,200 men had their bones examined and their exercise habits mapped. Of these, just over 2,300 18-year-olds were selected at random to have their heel bone examined by the researchers. The heel bone is particularly useful to study as it is directly impacted by exercise, being loaded with the full weight of the body.
"In this group, we found that those who actively did sports, and also those who used to do sports, had greater bone density than those who had never done sports," explains Martin Nilsson, physiotherapist and doctoral student at the Institute of Medicine.
The researchers also looked at bone density and structure in the lower leg in around 360 19-year-old men who had previously done sports but had now stopped training. They found that men who had stopped training more than six years ago still had larger and thicker bones in the lower leg than those who had never done sports.
"This result is particularly important, because we know that a bone with a large circumference is more durable and resistant to fractures than a narrower bone," says Nilsson.
The researchers also studied bone density throughout the body in around 500 randomly selected 75-year-old men. Those who had done competitive sports three or more times a week at some point between the ages of 10 and 30 had higher bone density in several parts of the body than those who had not.
The researchers have therefore established that there is a positive link between exercise while young and bone density and size. The connection is even stronger if account is taken of the type of sports done.
"The bones respond best when you're young, and if you train and load them with your own bodyweight during these years, it has a stimulating effect on their development," says Nilsson. "This may be important for bone strength much later in life too, so reducing the risk of brittle bones."
Energy in, energy out, it's the basic equation to weight loss, or is it? With more than two thirds of Americans classified as overweight or obese, a new study examines how motivation might be a large contributor to sticking with weight loss programs.
Researchers at the University of Kentucky and University of North Carolina at Chapel Hill examined two types of motivation, autonomous and controlled, and their relationship to adherence and weight loss in a 16-week Internet weight-loss intervention. To measure the 2 types of motivation, a Treatment Self-Regulation Questionnaire was used to identify those participants motivated by intrinsic and extrinsic controls such as feeling that performance is the best way to help oneself and making changes for personal reasons (autonomous motivation) and those participants motivated by only external controls such as perceived pressure from others and feelings of guilt (controlled motivation).
Motivation for weight loss was measured at baseline and 4, 8, 12, and 16 weeks. In addition, study participants recorded their food intake, exercise, and body weight through an on-line self-monitoring system weekly throughout the study.
Over half of the participants (37 of 66) lost 5% of initial body weight at the 16-week follow-up. To examine the relationship between the 2 different types of motivation and weight loss, the sample was divided into those who had and those who had not lost 5% of initial body weight by 16 weeks (37 and 29 participants, respectively).
The researchers found that the majority of participants had a significant increase in autonomous and controlled motivation between baseline and 4 weeks, though it's not clear what caused the increase in motivation at 4 weeks, the face-to-face session given at the start of the study, early success with weight loss, or something else. Although motivation increased initially for most participants, the group that went on to achieve a 5% weight loss sustained their autonomous motivation between 4 and 16 weeks, while the group that was less successful experienced a significant decrease in autonomous and controlled motivation over time.
The authors also found that autonomous motivation at 4 weeks was a significant predictor of adherence to self-monitoring and weight loss. Furthermore, this increase in self-monitoring appeared to be a way in which autonomous motivation led to better weight loss. The authors found a positive correlation between weight loss at 4 weeks and higher levels of autonomous motivation especially when compared to participants who had higher levels of controlled motivation.
The study appears in the May/June 2010 issue of the Journal of Nutrition Education and Behavior.
Writing in the article, the authors state, "It appears that the time period between 4 and 8 weeks may be an important window for weight control programs to consider using techniques designed to enhance autonomous motivation, including giving more intense support or different types of interventions, such as activities to enhance autonomous motivation or contact from a weight-loss counselor in the form of e-mails, phone calls, or face-to-face meetings."
"It is possible that motivation measured a few weeks after the study has begun more accurately captures motivation than baseline motivation for weight loss since participants have become familiar with the behavior changes that will be necessary for weight loss and can better gauge their motivation for making those changes. These findings suggest that building motivation may be an effective means of promoting adherence and weight loss."
Congratulations, you actually made it to the finish line after 26.2 miles of agony. You are exhausted and need some kind of recovery drink to pick you back up. Reach for the Gatorade? Chocolate milk? Water? No, your best bet is a big glass of tart cherry juice!
Dr Glyn Howatson, exercise physiologist and Laboratory Director in the School of Psychology and Sports Sciences at Northumbria University, examined the properties of Montmorency cherries in a study that found that athletes who drank the juice recovered faster after Marathon running than a placebo controlled group.
In the investigation, 20 marathon runners drank either a tart cherry blend juice or a placebo drink twice a day for five days before taking part in the London Marathon and for two days afterwards.
The findings indicated that the group who drank the cherry juice recovered their strength more rapidly than the control group over the 48-hour period following the marathon. Inflammation was also reduced in the cherry juice group, as was oxidative stress, a potentially damaging response that can be caused by strenuous physical activity, particularly long distance endurance exercise.
The study, which was run in collaboration with PhD student Jess Hill of St Mary's University College, concluded that cherry juice appears to aid recovery following strenuous exercise by increasing total antioxidative capacity, reducing inflammation and oxidative stress, hence aiding in the recovery of muscle function.
Dr Glyn Howatson(Credit: Image courtesy of Northumbria University)
Dr Howatson said: "Participating in long-distance endurance events, such as the London Marathon, causes a degree of muscle damage and inflammation for the runners. It takes several days to recover and during that period the runner's ability to conduct physical activity can be vastly inhibited.
"The phytochemicals, in particular, anthocyanins found in Montmorency cherries have anti-inflammatory and antioxidating properties, which the research has shown to be effective in helping exercisers to recover from strenuous physical activity."
Although it remains to be examined, Dr Howatson believes that the findings will not only benefit marathon runners but could also have serious implications in the treatment of people living with inflammatory diseases, such as arthritis.
He said: "If funding can be secured to embark on a further study, we can determine whether the use of tart cherry juice has implications for the management of some clinical pathologies that display high levels of inflammation and oxidative stress, such as rheumatoid arthritis and fibromyalgia.
"People are increasingly looking at natural remedies, or neutraceuticals, to treat their conditions, and scientific studies, such as the research into tart cherries, examine the potentially untapped treatments held in natural resources, that can provide adjunct therapy for the management of disease, which can help reduce negative symptoms and improve quality of life."
Source: Northumbria University and Howatson et al. Influence of tart cherry juice on indices of recovery following marathon running. Scandinavian Journal of Medicine and Science in Sports, 2009; DOI: 10.1111/j.1600-0838.2009.01005.x
Poor air quality apparently affects the running times of women in marathons, according to a study by Virginia Tech civil and environmental engineer Linsey Marr. Her findings come from a comprehensive study that evaluated marathon race results, weather data, and air pollutant concentrations in seven marathons over a period of eight to 28 years.
The top three male and female finishing times were compared with the course record and contrasted with air pollutant levels, taking high temperatures that were detrimental to performance into consideration.
Higher levels of particles in the air were associated with slower running times for women, while men were not significantly affected, Marr said. The difference may be due to the smaller size of women's tracheas, which makes it easier for certain particles to deposit there and possibly to cause irritation
"Although pollution levels in these marathons rarely exceeded national standards for air quality, performance was still affected," Marr said.
Her work, done in collaboration with Matthew Ely, an exercise physiologist at the U.S. Army Research Institute of Environmental Medicine, appears in the official journal of the American College of Sports Medicine, Medicine and Science in Sports & Exercise.
Her studies were conducted where major U.S. marathons are located, such as New York, Boston, and Los Angeles, where pollution tends to be highest. Although the person might not be significantly impacted by low-yet-still-acceptable air quality, marathoners are atypical because of their breathing patterns, she said.
"Previous research has shown that during a race, marathon runners inhale and exhale about the same volume of air as a sedentary person would over the course of two full days," Marr said. "Therefore, runners are exposed to much greater amounts of pollutants than under typical breathing conditions."
Particulate matter appeared to be the only performance-altering factor in air quality, with carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide levels not impacting race times.
Source: Virginia Tech and Marr, Linsey C.; Ely, Matthew R. Effect of Air Pollution on Marathon Running Performance :. Medicine & Science in Sports & Exercise, 2010; 42 (3): 585 DOI: 10.1249/MSS.0b013e3181b84a85
The usual excuse of "lack of time" for not doing enough exercise is blown away by new research published in The Journal of Physiology. The study, from scientists at Canada's McMaster University, adds to the growing evidence for the benefits of short term high-intensity interval training (HIT) as a time-efficient but safe alternative to traditional types of moderate long term exercise. Astonishingly, it is possible to get more by doing less!
"We have shown that interval training does not have to be 'all out' in order to be effective," says Professor Martin Gibala. "Doing 10 one-minute sprints on a standard stationary bike with about one minute of rest in between, three times a week, works as well in improving muscle as many hours of conventional long-term biking less strenuously."
HIT means doing a number of short bursts of intense exercise with short recovery breaks in between. The authors have already shown with young healthy college students that this produces the same physical benefits as conventional long duration endurance training despite taking much less time (and amazingly, actually doing less exercise!) However, their previous work used a relatively extreme set-up that involved "all out" pedaling on a specialized laboratory bicycle.
The new study used a standard stationary bicycle and a workload which was still above most people's comfort zone -about 95% of maximal heart rate -- but only about half of what can be achieved when people sprint at an all-out pace.
This less extreme HIT method may work well for people (the older, less fit, and slightly overweight among us) whose doctors might have worries about them exercising "all-out." We have known for years that repeated moderate long-term exercise tunes up fuel and oxygen delivery to muscles and aids the removal of waste products. Exercise also improves the way muscles use the oxygen to burn the fuel in mitochondria, the microscopic power station of cells.
Running or cycling for hours a week widens the network of vessels supplying muscle cells and also boosts the numbers of mitochondria in them so that a person can carry out activities of daily living more effectively and without strain, and crucially with less risk of a heart attack, stroke or diabetes.
But the traditional approach to exercise is time consuming. Martin Gibala and his team have shown that the same results can be obtained in far less time with brief spurts of higher-intensity exercise.
To achieve the study's equivalent results by endurance training you'd need to complete over 10 hours of continuous moderate bicycling exercise over a two-week period.
The "secret" to why HIT is so effective is unclear. However, the study by Gibala and co-workers also provides insight into the molecular signals that regulate muscle adaptation to interval training. It appears that HIT stimulates many of the same cellular pathways that are responsible for the beneficial effects we associate with endurance training.
The upside of doing more exercise is well-known, but a big question for most people thinking of getting fit is: "How much time out of my busy life do I need to spend to get the perks?"
Martin Gibala says "no time to exercise" is not an excuse now that HIT can be tailored for the average adult. "While still a demanding form of training," Gibala adds, "the exercise protocol we used should be possible to do by the general public and you don't need more than an average exercise bike."
The McMaster team's future research will examine whether HIT can bring health benefits to people who are overweight or who have metabolic diseases like diabetes.
As the evidence for HIT continues to grow, a new frontier in the fitness field emerges.
Highly fit multiple sclerosis patients perform significantly better on tests of cognitive function than similar less-fit patients, a new study shows. In addition, MRI scans of the patients showed that the fitter MS patients showed less damage in parts of the brain that show deterioration as a result of MS, as well as a greater volume of vital gray matter.
"We found that aerobic fitness has a protective effect on parts of the brain that are most affected by multiple sclerosis," said Ruchika Shaurya Prakash, lead author of the study and assistant professor of psychology at Ohio State University. "As a result, these fitter patients actually show better performance on tasks that measure processing speed."
The study, done with colleagues Robert Motl and Arthur Kramer of the University of Illinois and Erin Snook of the University of Massachusetts, Amherst, appears online in the journal Brain Research and will be published in a future print edition.
The study involved 21 women diagnosed with relapsing-remitting MS. They were compared with 15 age- and education-matched healthy female controls. The study assessed fitness, cognitive function, and structural changes in all participants. In order to measure fitness levels, the participants underwent a VO2 max test, in which they rode a stationary bicycle until they felt exhausted. During the test, they breathed into a mask which measured their oxygen consumption.
All the women also took a variety of tests designed to evaluate cognitive functions, such as processing speed and selective attention. In one test, for example, participants had to write down in one minute as many words as they could think of that began with the letter "F." MS patients generally perform poorly on these tests compared to healthy people. The third analysis involved MRIs of the participants, revealing any damage to their brains.
As expected, the MS patients did much worse than the healthy controls on the tests of brain functioning, and showed more deterioration in their brains as revealed through the MRIs. But what was interesting, Prakash said, was the significant differences between the more aerobically fit MS patients and those who were less fit.
Take, for instance, lesions, which are the characteristic feature of MS. Lesions are areas of inflammation in the central nervous system in which neurons have been stripped of myelin, an insulating protein.
"Physically fit MS patients had fewer lesions compared to those who weren't as fit and the lesions they did have tended to be smaller," Prakash said. "This is significant and can help explain why the higher-fit patients did better on tests of brain functioning."
Aerobic fitness was also associated with less-damaged brain tissue in MS patients, both the gray matter and white matter. Gray matter is the cell bodies in the brain tissue, while white matter is the fibers that connect the various gray matter areas.
The study found that fitness in MS patients was associated with larger volume of gray matter, accounting for about 20 percent of the volume in gray matter. That's important, Prakash said, because gray matter is linked to brain processing skills.
"Even in gray matter that appeared relatively healthy, we found a deterioration in the volume in MS patients," she said. "But for some of the highest fit MS patients, we found that their gray matter volume was nearly equivalent to that of healthy controls."
Another MRI analysis involved the integrity of the white matter in the brain. In MS patients, the white matter deteriorates as the myelin is stripped from neurons. Again, higher-fit MS patients showed less deterioration of white matter compared to those who were less fit.
Overall, the three MRI tests in this study showed that parts of the brain involved in processing speed are all negatively affected by MS -- but less so in patients who are aerobically fit.
Prakash noted that other researchers have found that exercise promotes the production of nerve growth factors, proteins which are important for the growth and maintenance of neurs in the brain. "Our hypothesis is that aerobic exercise enhances these nerve growth factors in MS patients, which increases the volume of the gray matter and increases the integrity of the white matter," she said. "As a result there is an improvement in cognitive function."
Prakash and her colleagues plan to extend this research by studying whether exercise interventions with MS patients can actually improve their cognition and have positive physical effects on the brain.
"For a long time, MS patients were told not to exercise because there was a fear it could exacerbate their symptoms," she said. "But we're finding that if MS patients exercise in a controlled setting, it can actually help them with their cognitive function."
The research was supported by a grant from the National Institute on Aging.
For winter sports athletes, including Olympians competing in Vancouver this week, the altitude of the sports venue can have a significant impact on performance, requiring athletes in skill sports, such as skating, ski jumping and snowboarding, to retool highly technical moves to accommodate more or less air resistance.
When considering the challenges and benefits of training and performing at sea level verses altitude, people often think of the effect altitude can have on oxygen delivery to muscles -- at higher altitudes, the body initially delivers less oxygen to muscles, which can result in fatigue occurring sooner during exercise. Higher altitudes also have less air density -- about 3 percent reduction for every 1,000 feet -- which can result in faster speeds in ski and skating races due to less aerodynamic drag, but can also affect timing and other technical components in skill sports.
"Many athletes perform thousands upon thousands of moves so they get a certain motor pattern ingrained," said Robert Chapman, an expert in altitude training at Indiana University. "A different altitude will change the feedback they get from balance and proprieception. In an endurance sport such as cross country skiing or biathlon, for competition at altitude it takes about 10-14 days to adjust. For a skill sport, it's harder to judge how long it will take to acclimate to the reduced air density at altitude. Hopefully, these athletes have incorporated this into their training, maybe in the last year or for a period of time, not just the two weeks leading up to competition."
Chapman, an exercise physiologist in the Department of Kinesiology in IU's School of Health, Physical Education and Recreation, wrote about the topic in a special Winter Olympics issue of the journal Experimental Physiology.
The Winter Olympics are being held in Vancouver, British Columbia, which is practically at sea level. The ice events also are nearly at sea level, with other venues ranging from altitudes of around 2,600 feet for the sled events to around 5,000 feet for women's and men's downhill skiing.
Shaun White enjoying some altitude
Chapman said fans should expect few record times in speed skating events because of the low altitude and greater air resistance facing athletes. He and his co-authors note in their paper that current world records for men and women in every long-track speed skating event from the 500-meter to 10,000-meter races were set in Olympics held in either Calgary, at an altitude of 3,400 feet, or Salt Lake City, with an altitude of 4,300 feet. They note that every Olympic record for all individual event distances was set at the 2002 Olympic Games in Salt Lake City, with none topped in the 2006 Winter Olympics held in Turin, which lies at an altitude of 784 feet.
"The general thought is that altitude slows you down because you have less oxygen going to your muscles," Chapman said. "But at altitude, just as it is easier to hit a home run in the thin air of Denver, speed skaters in Calgary and Salt Lake City could skate faster, move through the air faster, because there was less drag. Eight years after Salt Lake City, we have natural improvements that you'd expect to see involving training, coaching and technology, but we won't see many records in Vancouver. It doesn't mean the athletes are worse, if anything they're probably better. It's the effects of altitude on athletes' times."
Air density can have a dramatic effect on ski jumping, he said, requiring athletes to change the angle of their lean depending on the altitude. Chapman said the women's and men's Olympic downhill skiing, freestyle skiing and snowboarding events take place at higher altitudes this month and could require technical adjustments by the athletes.
Chapman and his co-authors make the following recommendations concerning training and performing at altitude:
Allow extra time and practice for athletes to adjust to changes in projectile motion. Athletes in sports such as hockey, shooting, skating and ski jumping may be particularly affected.
Allow time for acclimatization for endurance sports: Three to five days if possible, especially for low altitude (1,640-6,562 feet); one to two weeks for moderate altitude (6,562-9,843 feet); and at least two weeks if possible for high altitude (more than 9,843 feet). Chapman said altitude affects breathing, too, with breathing initially being harder at higher altitudes.
Increase exercise-recovery ratios as much as possible, with a 1:3 ratio probably optimal, and consider more frequent substitutions for sports where this is allowed, such as ice hockey. Recovery refers to the amount of time an athlete eases up during practice between harder bouts. If an athlete runs hard for one minute, following this with three minutes of slower running would be optimal before the next sprint. The recovery period gives athletes more time to clear lactic acid build up from their muscles.
Consider the use of supplemental oxygen on the sidelines in ice hockey or in between heats in skating and Alpine skiing to help with recovery. Chapman said this helps calm breathing, which can be more difficult at altitude.
Living at high altitudes while training at low altitudes can help athletes in endurance sports improve performance at lower altitudes.
If you’re prone to worrying whether your ‘butt looks big in this’, particularly after the holidays, you can take comfort that there may be health benefits.
Oxford University scientists – who have looked at all the evidence on the health effects of storing more fat on the hips, thighs and bum, rather than around the waist – show that having a ‘pear shape’ is not just less bad for you than an ‘apple shape’, but actively protects against diabetes and heart disease.
The team from the Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM) have published their summary of the latest research in the International Journal of Obesity today.
‘The idea that body fat distribution is important to health has been known for some time,’ says Dr Konstantinos Manolopoulos, one of the paper’s authors along with Dr Fredrik Karpe and Professor Keith Frayn.
‘However, it is only very recently that thigh fat and a larger hip circumference have been shown to promote health, that lower body fat is protective by itself.’
He adds: ‘This protective effect is independent of weight. However, if you put on weight, thigh circumference will increase but your waist circumference will also increase, which over-rides the protective effect.’
‘Control of body weight is still the best way to stay healthy, and the advice remains the same: it is important to eat less and exercise more.’
The Oxford researchers explain that the body uses its fat tissues to store energy in the form of fatty acids, which can be released when needed, for example after heavy exercise or a period of starvation. Both tummy and thigh fat handle this process, but fat around the waist is much more active in storing and releasing fatty acids in response to need throughout the day. Thigh fat is used for much longer term storage.
More waist or abdominal fat tends to lead to more fatty acids floating around the body where it can get deposited in other organs like the liver and muscle, and cause harm. This is associated with conditions like diabetes, insulin resistance and heart disease.
Thigh fat on the other hand, traps the fatty acids long term, so they can’t get deposited and cause harm.
'Thigh fat and a larger hip circumference have been shown to promote health, and lower body fat is protective by itself,' said Manolopoulos.
The scientists also review evidence that abdominal fat and thigh fat release different levels of hormones. Waist fat is known to release molecules called pro-inflammatory cytokines, and inflammation is a process linked to diabetes and heart disease.
Thigh fat might also secrete more beneficial hormones like leptin and adiponectin, Dr Manolopoulos says, although this is unclear at the moment.
Dr Manolopoulos says the typical difference in male and female body shapes, with men more likely to have fat around the waist and women have more fat on their thighs and hips, neatly illustrates the health effects of different body shapes.
‘If you looked at a man and woman of the same weight and aged around 40, they would have different weight distributions, and it would be the man that was at higher risk of diabetes and heart disease,’ he says.
‘However, when women go through menopause, as well as changes in their hormones they tend to see a change in body shape. They lose body fat and move to a more ‘male’ fat distribution. They then have the same risk of heart disease and diabetes as men.’
It may be possible to use these findings in the future to reduce people’s health risks but that is a long way off, cautions Dr Manolopoulos.
‘We don’t really know how the body decides where to store fat. At the moment we need to understand more about the mechanisms the body uses. Only then will we be able to take the next step and try to influence this.’
‘In principle, this should be possible. There is a class of anti-diabetic drugs that is known to redistribute fat in the body from internal organs to fat stored subcutaneously under the skin. This improves symptoms in diabetes,’ he says.
The team at OCDEM, funded by the Wellcome Trust, is working to understand the way the body stores and turns over fat. They recently pinpointed two genes that are associated with differences in people’s body fat distribution and may be important during embryo development.
‘They are weak effects, but this is just a beginning,’ says Dr Karpe, one of the research group heads. ‘Obesity is a big problem, but it may be that the characteristics of that obesity are more important.’
Knee osteoarthritis (OA) accounts for more disability in the elderly than any other disease. Running, although it has proven cardiovascular and other health benefits, can increase stresses on the joints of the leg. In a study published in the December 2009 issue of PM&R: The journal of injury, function and rehabilitation, researchers compared the effects on knee, hip and ankle joint motions of running barefoot versus running in modern running shoes. They concluded that running shoes exerted more stress on these joints compared to running barefoot or walking in high-heeled shoes.
Sixty-eight healthy young adult runners (37 women), who run in typical, currently available running shoes, were selected from the general population. None had any history of musculoskeletal injury and each ran at least 15 miles per week. A running shoe, selected for its neutral classification and design characteristics typical of most running footwear, was provided to all runners. Using a treadmill and a motion analysis system, each subject was observed running barefoot and with shoes. Data were collected at each runner's comfortable running pace after a warm-up period.
The researchers observed increased joint torques at the hip, knee and ankle with running shoes compared with running barefoot. Disproportionately large increases were observed in the hip internal rotation torque and in the knee flexion and knee varus torques. An average 54% increase in the hip internal rotation torque, a 36% increase in knee flexion torque, and a 38% increase in knee varus torque were measured when running in running shoes compared with barefoot.
These findings confirm that while the typical construction of modern-day running shoes provides good support and protection of the foot itself, one negative effect is the increased stress on each of the 3 lower extremity joints. These increases are likely caused in large part by an elevated heel and increased material under the medial arch, both characteristic of today's running shoes.
Writing in the article, lead author D. Casey Kerrigan, MD, JKM Technologies LLC, Charlottesville, VA, and co-investigators state, "Remarkably, the effect of running shoes on knee joint torques during running (36%-38% increase) that the authors observed here is even greater than the effect that was reported earlier of high-heeled shoes during walking (20%-26% increase). Considering that lower extremity joint loading is of a significantly greater magnitude during running than is experienced during walking, the current findings indeed represent substantial biomechanical changes."
Dr. Kerrigan concludes, "Reducing joint torques with footwear completely to that of barefoot running, while providing meaningful footwear functions, especially compliance, should be the goal of new footwear designs."
Source: Elsevier Health Sciences "The Effect of Running Shoes on Lower Extremity Joint Torques" by D. Casey Kerrigan, MD, Jason R. Franz, MS, Geoffrey S. Keenan, MD, Jay Dicharry, MPT, Ugo Della Croce, PhD, and Robert P. Wilder, MD. It appears in PM&R: The journal of injury, function and rehabilitation, Volume 1, Issue 12 (December 2009), published by Elsevier. The article has been made freely available and may be accessed at: http://www.pmrjournal.org/article/S1934-1482(09)01367-7/fulltext
With the Fall marathon season in full swing, thousands of runners are gearing up for the big day. Just as important as their broken-in shoes and heart rate monitor is their source of motivation, inspiration and distraction: their tunes.
Running with music has become so common that the two biggest names in both industries, Nike and Apple, have been joined at the hip with the Nike + iPod combination. So, what is it about music and running, or any exercise, that feels so right?
Several recent studies try to chase down the connection between our ears and our feet.
For the last 20 years, Costas Karageorghis, a sports psychologist at Britain’s Brunel University, has been setting the research pace for understanding our need to groove and move.
In addition to his lab research, Karageorghis has helped create a half marathon in London that tries to find the perfect music mix of live bands based on his research of human reaction to rhythm. The second annual "Run to the Beat" event was held a few weeks ago with 9,000 laboratory rats, er, runners either enjoying the live music or listening to their own mix of tunes on their MP3. Karageorghis even offered a scientific selection of songs based on his findings.
According to Kargeorghis, there are four factors that contribute to a song's motivational qualities: rhythm response, musicality, cultural impact and association.
The first two are known as "internal" factors as they relate to the music's structure while the second two are "external" factors that reflect how we interpret the music. Rhythm response is tied to the beats per minute (bpm) of the song and how well it matches either the cadence or the heartbeat of the runner. A song's structure such as its melody and harmony contribute to its musicality. The external factors consider our musical background and the preferences we have for a certain genre of music and what we have learned to associate with certain songs and artists.
Picking the right music can have several benefits.
Syncing beats per minute with an exercise pace increases your efficiency. In a recent study, subjects who cycled in time to music found that they required 7 percent less oxygen to do the same work when compared to music playing in the background. Music can also help block out the little voice in your brain telling you its time to quit. Research shows that this dissociation effect results in a 10 percent reduction in perceived effort during treadmill running at a moderate intensity.
In the current study, published in the Journal of Sport and Exercise Psychology, 30 subjects synchronised their pace to the tempo of the music which was 125 bpm. Before the experiment, a pool of music was rated using a questionnaire tool (the Brunel Music Rating Inventory) which then selected the most motivational pieces for the treadmill test. The subjects were given a choice of either pop or rock music.
When compared to a no-music control, the motivational synchronised music led to a 15 percent improvement in endurance.
"The synchronous application of music resulted in much higher endurance while the motivational qualities of the music impacted significantly on the interpretation of fatigue symptoms right up to the point of voluntary exhaustion," Karageorghis reported.
Matching the beats per minute of our music with our exercise heart rate also takes an interesting non-linear path, according to research.
Karageorghis found that when our hearts are performing at between 30 and 70 percent of maximum, we prefer a somewhat linear increase from 90 to 120 bpm. However, when we reach our anaerobic threshold between 70 and 80 percent of maximum, we prefer a jump in rhythm from 120 to 150 bpm. Above 80 percent of maximum heart rate, a plateau is reached where even faster music is not preferred.
Another new study by researchers from Liverpool John Moores University, and detailed online in the Scandinavian Journal of Medicine & Science in Sports, looked at the tempo angle differently. Instead of a mix of different songs at different tempos, they asked a group of cyclists to pedal to the same song over three different trials.
What the subjects did not know is that the researchers first played the song at normal speed, but then increased or decreased the speed of the same song by 10 percent. The small change was not enough to be noticed, but it did have an effect on performance.
Speeding up the music program increased distance covered/unit time, power and pedal cadence by 2.1 percent, 3.5 percent and 0.7 percent, respectively. Slowing the program produced falls of 3.8 percent, 9.8 percent and 5.9 percent. The researchers concluded that we increase or decrease our work effort and pace to match the tempo of our music.
Finding the right beat has now become even easier with a couple of cool software plug-in tools, Cadence or Tangerine. Cadence is an iPhone/iPod Touch app, while Tangerine is Mac only. By integrating with your iTunes library, they can build a custom playlist based on the BPM range you provide, while arranging the songs in several different tempo shapes including warm-ups and warm-downs. With the right mix, your brain and feet will be in perfect harmony.
Here’s a question for your buddies at the next golf outing or bowling league night: Are we more active because we drink more or do we drink more because we’re more active? Recent research showed that there is a correlation between the two, but could not offer a solid reason.
Either way, another study claims the combination of moderate alcohol use and exercise will help our hearts more than just choosing one over the other.
Michael French, a health economics professor at the University of Miami, and his colleagues dug into data from the 2005 Behavioral Risk Factor Surveillance System, a yearly telephone survey of roughly 230,000 Americans, and found a surprisingly strong positive correlation between the levels of alcohol intake and exercise. For both men and women, those who drank at least some alcohol exercised 7.2 minutes more per week than non-drinkers.
While that may not seem like much, the study showed that the more booze, the more minutes spent sweating. Light, moderate, and heavy drinkers worked out 5.7, 10.1 and 19.9 minutes more per week, respectively. Also, drinking resulted in a 10.1 percent increase in the probability of vigorous physical activity.
Now, that doesn’t mean that these folks were drinking while exercising, nor that it was necessarily good for them to engange in more than light drinking. Instead, French and his team, who have studied many facets of alcohol abuse and its triggers, are trying to make sense of this correlation that seems too strong to ignore. It seems counterintuitive to traditional views that if people engage in one unhealthy behavior, like excessive drinking, that they will most likely engage in other unhealthy behaviors, like physical inactivity.
French suggests that heavy alcohol use may be masked by the appearance of a healthy lifestyle and cautions physicians not to jump to conclusions.
“For example, taking into account only the patients’ levels of physical activity and perhaps diet would overlook potential alcohol use problems that could be detected and treated,” French writes. “Physically active individuals who engage in problematic drinking are often ‘‘healthy looking,’’ because alcohol use consequences are sometimes delayed.”
The study appears in the September/October issue of American Journal of Health Promotion.
Maybe we exercise more because we know how many calories those beers and mixers are adding to our waistlines. Even so, Danish researchers found that we’re still better off combining moderate alcohol consumption with exercise.
Morten Gronbaek, epidemiologist with Denmark’s National Institute of Public Health, and his team surveyed 12,000 people over a 20-year period to determine the cardiovascular effects of alcohol use and exercise. They divided the population into four groups: those who did not drink or exercise; those who had both moderate levels of alcohol use and exercise; and those who either just drank or just exercised at moderate levels.
The group with the highest risk of fatal ischaemic heart disease, a form of heart disease characterized by a reduced blood supply to the heart, were the non-drinking, non-exercisers. Choosing either moderate drinking or moderate exercise provided a 30 percent decrease in risk factors. However, drinking and exercising, (not necessarily at the same time), showed a 50 percent lower risk.
Their findings were detailed in the European Heart Journal.
“Being both physically active and drinking a moderate amount of alcohol is important for lowering the risk of both fatal IHD and death from all causes,” Gronbaek concluded. Of course, the key is moderation, defined in the study as one drink per day for women and two per day for men. Also, Gronbaek warns that there is no heart benefit until a certain age.
“You wouldn’t advise everyone to drink,” he said. “You shouldn’t even think about doing it until age 45 or 50. There’s absolutely no proof of a preventative and protective effect before age 45.”
Well, maybe Usain Bolt was right after all. As discussed in our Physiology of Speed story, Bolt predicted he could run 100 meters in 9.54 seconds, lowering his own world record of 9.69 seconds.
Earlier this week, he almost got there running a 9.58 at the World Championships in Berlin.
Now, researchers from Tilburg University in the Netherlands say he could shave another 3/100ths of a second off and hit the tape at 9.51 seconds.
Using the "extreme value theory", Professor of Statistics John Einmahl and former student Sander Smeets have calculated the fastest possible times for men and women. Between 1991 and 2008, they chronicled the best times for 762 male sprinters and 469 female sprinters. They did not trust the data prior to 1991 as possibly being tainted by doping athletes (not that's its gotten much better since then.)
For females, their current world record, set by Florence Griffith-Joyner, of 10.49 seconds could be theoretically lowered to 10.33 seconds.
Extreme value theory is a branch of statistics that tries to predict extreme events such as 100-year floods or major stock market movements that deviate signficantly from the median. With less statistical confidence (95% confidence), Einmahl estimates the men could get to 9.21 while the women could run a 9.88.
To make this statistical postulating a reality, Bolt needs to find the secret competitive edge that will shave these tenths and hundredths of seconds away. Scientists at the Research Institute of Wildlife Ecology in Austria claim sunflower oil may be the super fuel that is missing.
They found that mice fed a diet high in sunflower oil, which contains n-6 polyunsaturated fatty acids, were 6.3% faster in sprint races against mice fed a diet rich in linseed oil, which is high in n-3 fatty acids.
Their research was presented in June at the Society for Experimental Biology Annual Meeting.
"The results of the current study on mice suggest that moderate differences in dietary n-6/n-3 polyunsaturated fatty acid intake can have a biologically meaningful effect on maximum running speed", says Dr Christopher Turbill, lead researcher. "The application of this research to the performance of elite athletes (specifically those in sports that involve short distance sprints, including cycling) is uncertain, but in my opinion certainly deserves some further attention" he said.
So, a little sunflower oil mixed into the pre-race Gatorade? It might work until world records start to fall and its added to the banned substance list.
Usain Bolt, the triple Olympic gold medal sprinter from Jamaica, predicted last week that he could break his own world record of 9.69 seconds in the 100 meter sprint with a time as low as 9.54 seconds. (8/15 update: he came very close running a 9.58 at the World Championships in Berlin.)
He claimed his coach told him its possible, so he believes him. His coach, Glen Mills, may have just finished reading some new research coming out of Duke University that showed sprinters and swimmers who are taller, heavier but more slender are the ones breaking world records.
At first glance, it may not make sense that bigger athletes would be faster. However, Jordan Charles, a recent engineering grad at Duke, plotted all of the world record holders in the 100 meter sprint and the 100 meter swim since 1900 against their height, weight and a measurement he called "slenderness."
World record sprinters have gained an average of 6.4 inches in height since 1900, while champion swimmers have shot up 4.5 inches, compared to the mere mortal average height gain of 1.9 inches.
During the same time, about 7/10 of a second have been shaved off of the 100-meter sprint while over 14 seconds have come off the 100-meter swim record.
What's going on
Charles applied the "constructal theory" he learned from his mentor Adrian Bejan, a mechanical engineering professor at Duke, that describes how objects move through their environment.
"Anything that moves, or anything that flows, must evolve so that it flows more and more easily," Bejan said. "Nature wants to find a smoother path, to flow more easily, to find a path with less resistance," he said. "The animal design never gets there, but it tries to be the least imperfect that it can be."
Their research is reported in the current online edition of the Journal of Experimental Biology.
For locomotion, a human needs to overcome two forces, gravity and friction. First, an athlete would need to lift his foot off the ground or keep his body at the water line without sinking. Second, air resistance for the sprinter and water resistance for the swimmer will limit speed.
So, the first step is actually weight lifting, which a bigger, stronger athlete will excel at. The second step is to move through the space with the least friction, which emphasizes the new slenderness factor.
By comparing height with a calculated "width" of the athlete, slenderness is a measurement of mass spread out over a long frame. The athlete that can build on more muscle mass over a aerodynamic frame will have the advantage.
The numbers
In swimming, legendary Hawaiian champion Duke Kahanamoku set the world record in 1912 with a time of 61.6 seconds with a calculated slenderness of 7.88. Some 96 years later, Eamon Sullivan lowered the world mark to 47.05 seconds at a slenderness factor of 8.29.
As the athletes’ slenderness factor has risen over the years, the winning times have dropped. In 1929, Eddie Tolan's world-record 100 meter sprint of 10.4 seconds was achieved with a slenderness factor of 7.61. When Usain Bolt ran 9.69 seconds in the 2008 Olympics, his slenderness was also 8.29 while also being the tallest champion in history at 6-feet 5-inches.
“The trends revealed by our analysis suggest that speed records will continue to be dominated by heavier and taller athletes,” said Charles. “We believe that this is due to the constructal rules of animal locomotion and not the contemporary increase in the average size of humans.”
So, how fast did the original Olympians run? Charles used an anthropology finding for Greek and Roman body mass and plugged it into his formula.
“In antiquity, body weights were roughly 70 percent of what they are today,” Charles said. “Using our theory, a 100-meter dash that is won in 13 seconds would have taken about 14 seconds back then.”
Bolt puts his prediction to the test next month at the track and field world championships in Berlin. One of his main competitors is Asafa Powell, the previous world record holder, who is shorter and has a slenderness factor of 7.85. My money is on the Lightning Bolt.
After an hour of sweating on the treadmill or pumping iron, most of us look forward to the extra post-exercise "afterburn" of fat cells that has been promised to us by fitness pundits. This 24-hour period of altered metabolism is supposed to help with our overall weight loss.
Unfortunately, a recent study found this to be a myth for moderate exercisers.
The new research clarifies a misunderstanding that exercisers can ignore their diet after a workout because their metabolism is in this super active state.
"It's not that exercise doesn't burn fat," said Edward Melanson, associate professor of medicine at the University of Colorado, "It's just that we replace the calories. People think they have a license to eat whatever they want, and our research shows that is definitely not the case. You can easily undo what you set out to do.”
The findings were detailed in the April edition of Exercise and Sport Sciences Review.
What does happen
Melanson and his team set out to measure whether people were able to burn more calories for the 24 hours after a workout compared to a day with no exercise. Their test groups, totaling 65 volunteers, included a mix of lean vs. obese and active vs. sedentary people.
On exercise days, they rode stationary bikes until they had burned 400 calories. Their pre and post exercise diet was controlled.
Throughout the groups, there was no difference in the amount of fat burned in the 24-hour period either with or without exercise. Of course, during the exercise plenty of calories were being burned and that's the formula that Melanson would like us to remember. "If you are using exercise to lose body weight or body fat, you have to consider how many calories you are expending and how many you are taking in," Melanson recently told WebMd. The daily energy balance or "calories in vs. calories out" is the most reliable equation for long-term weight loss.
While the current research focused on the moderate activity levels of most people, the researchers admitted they still need to examine the effect of higher intensity workouts and multiple consecutive days of exercise.
They are clear on their current message. "We suggest that it is time to put the myth that low intensity exercise promotes a greater fat burn to rest," Melanson writes. "Clearly, exercise intensity does not have an effect on daily fat balance, if intake is unchanged."
Type of workout
So, how about a weight resistance training program mixed in with cardio work? Another fitness industry claim is that more muscle mass on your frame will raise your metabolism rate, even while sitting on the couch.
The same study, using the same test groups, found the post-exercise rate of calorie burn did not change on days of lifting versus no lifting. It is true that a pound of muscle burns seven to ten calories per day versus only two calories per day for a pound of fat. However, the average adult just doesn't put on enough lean muscle mass to make this difference significant.
While this research dispels one myth about exercise, there is still overwhelming evidence of the benefits of movement when combined with your eating habits. So, before eating that double cheeseburger and fries, you might want to do some math to figure out how many stairs you'll have to climb to break even.
Please visit my other sports science articles at Livescience.com
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