Archive for the ‘Walking’ Category

Women who walked two or more hours a week or who usually walked at a brisk pace (3 miles per hour or faster) had a significantly lower risk of stroke than women who didn’t walk, according to a large, long-term study reported in Stroke: Journal of the American Heart Association.

The risks were lower for total stroke, clot-related (ischemic) stroke and bleeding (hemorrhagic) stroke, researchers said.

Compared to women who didn’t walk:

  • Women who usually walked at a brisk pace had a 37 percent lower risk of any type of stroke and those who walked two or more hours a week had a 30 percent lower risk of any type of stroke.
  • Women who typically walked at a brisk pace had a 68 percent lower risk of hemorrhagic stroke and those who walked two or more hours a week had a 57 percent lower risk of hemorrhagic stroke.
  • Women who usually walked at a brisk pace had a 25 percent lower risk of ischemic stroke and those who usually walked more than two hours a week had a 21 percent lower risk of ischemic stroke — both “borderline significant,” according to researchers.

“Physical activity, including regular walking, is an important modifiable behavior for stroke prevention,” said Jacob R. Sattelmair, M.Sc., lead author and doctoral candidate in epidemiology at Harvard School of Public Health in Boston, Mass. “Physical activity is essential to promoting cardiovascular health and reducing risk of cardiovascular disease, and walking is one way of achieving physical activity.”

More physically active people generally have a lower risk of stroke than the least active, with more-active persons having a 25 percent to 30 percent lower risk for all strokes, according to previous studies.

“Though the exact relationship among different types of physical activity and different stroke
subtypes remains unclear, the results of this specific study indicate that walking, in particular, is associated with lower risk of stroke,” Sattelmair said.

Researchers followed 39,315 U.S. female health professionals (average age 54, predominantly white) participating in the Women’s Health Study. Every two to three years, participants reported their leisure-time physical activity during the past year — specifically time spent walking or hiking, jogging, running, biking, doing aerobic exercise/aerobic dance, using exercise machines, playing tennis/squash/racquetball, swimming, doing yoga and stretching/toning. No household, occupational activity or sedentary behaviors were assessed.

They also reported their usual walking pace as no walking, casual (about 2 mph), normal (2.9 mph), brisk (3.9 mph) or very brisk (4 mph).

Sattelmair noted that walking pace can be assessed objectively or in terms of the level of exertion, using a heart rate monitor, self-perceived exertion, “or a crude estimate such as the ‘talk test’ – wherein, for a brisk pace, you should be able to talk but not able to sing. If you cannot talk, slow down a bit. If you can sing, walk a bit faster.”

During 11.9 years of follow-up, 579 women had a stroke (473 were ischemic, 102 were hemorrhagic and four were of unknown type).

The women who were most active in their leisure time activities were 17 percent less likely to have any type of stroke compared to the least-active women.

Researchers didn’t find a link between vigorous activity and reduced stroke risk. The reason is unclear, but they suspect that too few women reported vigorous activity in the study to get an accurate picture and/or that moderate-intensity activity may be more effective at lowering blood pressure as suggested by some previous research.

Stroke is the third leading cause of death and a leading cause of serious disability in the United States, so it’s important to identify modifiable risk factors for primary prevention, Sattelmair said.

An inverse association between physical activity and stroke risk is consistent across genders. But there tend to be differences between men and women regarding stroke risk and physical activity patterns.

“The exact relation between walking and stroke risk identified in this study is not directly generalizable to men,” Sattelmair said. “In previous studies, the relation between walking and stroke risk among men has been inconsistent.”

The study is limited because it was observational and physical activity was self-reported. But strengths are that it was large and long-term with detailed information on physical activity, he said.

Further study is needed on more hemorrhagic strokes and with more ethnically diverse women, Sattelmair said.

The American Heart Association recommends for substantial health benefits, adults should do at least 150 minutes a week of moderate-intensity or 75 minutes a week of vigorous-intensity aerobic physical activity or a combination.

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Article adapted by MD Sports from original press release.
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Contact: Birdgette McNeill
American Heart Association

A University of Colorado at Boulder study of a space-age, low-gravity training machine used by several 2008 Olympic runners showed it reduced impacts on muscles and joints by nearly half when subjects ran at the equivalent of 50 percent of their body weight.

The new study has implications for both competitive runners rehabilitating from injuries and for ordinary people returning from knee and hip surgeries, according to Associate Professor Rodger Kram of CU-Boulder’s integrative physiology department.

Known as the “G-Trainer,” the machine consists of a treadmill surrounded by an inflatable plastic chamber that encases the lower body of the runner, said Kram. Air pumped into the chamber increases the pressure and effectively reduces the weight of runners, who are sealed in the machine at the waist in a donut-shaped device with a special zipper and “literally lifted up by their padded neoprene shorts,” he said.

Published in the August issue of the Journal of Applied Biomechanics, the study is the first to quantify the effects of running in the G-Trainer, built by Alter-G Inc. of Menlo Park, Calif., using technology developed at NASA’s Ames Research Center in California. The paper was authored by Kram and former CU-Boulder doctoral student Alena Grabowski, now a postdoctoral researcher at the Massachusetts Institute of Technology.

Although G-Trainers have been used in some sports clinics and college and professional sports training rooms since 2006, the new study is the first scientific analysis of the device as a training tool for running, said Grabowski.

“The idea was to measure which levels of weight support and speeds give us the best combination of aerobic workout while reducing the impact on joints,” said Kram. “We showed that a person can run faster in the G-Trainer at a lower weight and still get substantial aerobic benefits while maintaining good neuromuscular coordination.”

The results indicated a subject running at the equivalent of half their weight in the G-Trainer at about 10 feet per second, for example — the equivalent of a seven-minute mile — decreased the “peak” force resulting from heel impact by 44 percent, said Grabowski. That is important, she said, because each foot impact at high speed can jar the body with a force equal to twice a runner’s weight.

Several former CU track athletes participating in the 2008 Olympics in Beijing have used the machine, said Kram. Alumna Kara Goucher, who will be running the 5,000- and 10,000-meter races in Beijing, has used the one in Kram’s CU-Boulder lab and one in Eugene, Ore., for rehabilitation, and former CU All-American and Olympic marathoner Dathan Ritzenhein also uses a G-Trainer in his home in Oregon. Other current CU track athletes who have been injured have tried the machine in Kram’s lab and found it helpful to maintain their fitness as they recovered, Kram said.

For the study, the researchers retrofitted the G-Trainer with a force-measuring treadmill invented by Kram’s team that charts vertical and horizontal stress load on each foot during locomotion, measuring the variation of biomechanical forces on the legs during running. Ten subjects each ran at three different speeds at various reduced weights, with each run lasting seven minutes. The researchers also measured oxygen consumption during each test, Kram said.

Grabowski likened the effect of the G-Trainer on a runner to pressurized air pushing on the cork of a bottle. “If you can decrease the intensity of these peak forces during running, then you probably will decrease the risk of injury to the runner.”

The G-Trainer is a spinoff of technology originally developed by Rob Whalen, who conceived the idea while working at NASA Ames as a National Research Council fellow to help astronauts maintain fitness during prolonged space flight. While the NASA technology was designed to effectively increase the weight of the astronauts to stem muscle atrophy and bone loss in low-gravity conditions, the G-Trainer reverses the process, said Grabowski.

In the past, sports trainers and researchers have used climbing harnesses over treadmills or flotation devices in deep-water swimming pools to help support the weight of subjects, said Kram. Harnesses are cumbersome, while pool exercises don’t provide sufficient aerobic stimulation and biomechanical loading on the legs, he said.

Marathon world-record holder Paula Radcliffe of Great Britain is currently using a G-Trainer in her high-altitude training base in Font-Remeu, France. Radcliffe is trying to stay in top running shape while recovering from a stress fracture in her femur in time for the 2008 Olympic women’s marathon on Aug. 17, according to the London Telegraph.

Kram and Grabowski have begun a follow-up study of walking using the G-Trainer. By studying subjects walking at various weights and speeds in the machine, the researchers should be able to quantify its effectiveness as a rehabilitation device for people recovering from surgeries, stress fractures and other lower body injuries, Kram said.

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Article adapted by MD Sports from original press release.
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Contact: Rodger Kram
University of Colorado at Boulder

Boosting an exercise-related gene in the brain works as a powerful anti-depressant in mice—a finding that could lead to a new anti-depressant drug target, according to a Yale School of Medicine report in Nature Medicine.

“The VGF exercise-related gene and target for drug development could be even better than chemical antidepressants because it is already present in the brain,” said Ronald Duman, professor of psychiatry and senior author of the study.

Depression affects 16 percent of the population in the United States, at a related cost of $83 billion each year. Currently available anti-depressants help 65 percent of patients and require weeks to months before the patients experience relief.

Duman said it is known that exercise improves brain function and mental health, and provides protective benefits in the event of a brain injury or disease, but how this all happens in the brain is not well understood. He said the fact that existing medications take so long to work indicates that some neuronal adaptation or plasticity is needed.

He and his colleagues designed a custom microarray that was optimized to show small changes in gene expression, particularly in the brain’s hippocampus, a limbic structure highly sensitive to stress hormones, depression, and anti-depressants.

They then compared the brain activity of sedentary mice to those who were given running wheels. The researchers observed that the mice with wheels within one week were running more than six miles each night. Four independent array analyses of the mice turned up 33 hippocampal exercise-regulated genes—27 of which had never been identified before.

The action of one gene in particular—VGF—was greatly enhanced by exercise. Moreover, administering VGF functioned like a powerful anti-depressant, while blocking VGF inhibited the effects of exercise and induced depressive-like behavior in the mice.

“Identification of VGF provides a mechanism by which exercise produces antidepressant effects,” Duman said. “This information further supports the benefits of exercise and provides a novel target for the development of new antidepressants with a completely different mechanism of action than existing medications.”

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Article adapted by MD Sports Weblog from original press release.
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Contact: Jacqueline Weaver
Yale University
Nature Medicine

A new pair of studies compare step counts needed to meet 1) ACSM/CDC recommendations for moderate physical activity and 2) a one-mile mark. Both studies are useful as suggested step-based guidelines for meeting physical activity recommendations.

The first study, funded by the Centers for Disease Control and Prevention, was designed to translate ACSM/CDC public health guidelines for 30 minutes of daily moderate-intensity physical activity into steps. Researchers at San Diego State University and Arizona State University utilized commercial pedometers on a community sample of adults. Their results support an approximate 100 step/minute recommendation for minimally moderate intensity. To meet ACSM/CDC recommendations, this equates to 3,000 steps in 30 minutes, or three daily bouts of 1,000 steps in 10 minutes.

While pedometers are useful tools to measure step counts, this team notes pedometer-derived steps should be used with caution for gauging moderate intensity walking. Step counts associated with moderate intensity walking should be individualized based on stride length and level of fitness. ACSM defines moderate intensity walking as “brisk” walking, or “walking with purpose.” Walkers should be able to talk comfortably at a moderate-intensity level, but still feel exertion. Other definitions have included a pace at which you break a sweat and/or have a slight increase in your heart rate.

“Walking is one of the easiest forms of physical activity, and one that most people can do to meet recommendations for daily exercise,” said Simon J. Marshall, Ph.D., lead author of the study. “Most people have an instinct about the length of time or the distance they walk. A pedometer can help count steps, but when you also try to walk at least 1000 steps in 10 minutes on a regular basis, you may gain significant health benefits. For inactive people, setting smaller targets can help them start a program to meet general physical activity guidelines and enhance their health and wellness.”

In the one-mile study, researchers at Boise State University wanted to determine the number of steps individuals take while walking one mile at 20 and 15-minute paces and while running the same distance at 12, 10, eight, and six-minute paces. One mile (1,609 meters) step count varies at different walking and running speeds and can be predicted based on gender, pace, and height or leg length.

The average number of steps required to run/walk a mile ranged from 1,064 steps for a six-minute-mile pace in men to 2,310 steps for a 20-minute per mile walk in women. An interesting finding is that on average, individuals took more steps while running (jogging) a 12-minute mile than while walking a 15-minute mile (1,951 vs.1,935 steps, respectively). This finding is most likely related to the smaller distance between steps that people tend to take while jogging at the slower speed (12-minute mile) compared to walking at a 15-minute per mile pace.

“A ‘mile’ appears to be universally known as a marker of distance for walkers and runners to measure their activity achievements,” said Werner Hoeger, Ed.D., FACSM, lead author. “To estimate the number of steps required to walk or run a mile at selected speeds is likely to help people who monitor their steps with a pedometer with the objective of increasing their fitness by working up the miles.”

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Article adapted by MD Sports Weblog from original press release.
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The American College of Sports Medicine is the largest sports medicine and exercise science organization in the world. More than 20,000 international, national, and regional members are dedicated to advancing and integrating scientific research to provide educational and practical applications of exercise science and sports medicine.

http://www.acsm.org

It actually takes approximately twice as much time to take the elevator when ascending or descending one floor.  To test this, researchers at the University of South Carolina recorded the time required to ascend and descend one floor by taking the stairs and elevator over several days.  A small group of participants were instructed to alternate between elevator and stair use and to take the stairs at a self-selected “normal” pace during the course of their daily routine.

The time required to take the elevator was significantly greater than the time required to use the stairs going both up and down one floor. The excess time required when taking the elevator was attributed to the wait, not the travel time, since the actual elevator ride was measured at approximately 10 seconds.  The time required to ascend the stairs was greater than the time to descend the stairs, while there was no significant difference between taking the elevator up and elevator down one floor.

The study team hopes this information can be used as part of an intervention to increase stair use, where specific and relevant messages have been shown to be effective in encouraging physical activity.

“If climbing the stairs a few floors saves you time and adds to the physical activity you can accumulate throughout the day, it’s a win-win,” said researcher Joshua Westmeier-Shuh, lead author of the study.  “Let’s look first at shifting the perception that the elevator is a better choice when rushing to work or thinking about how to incorporate activity into the day, and then think about the implications this can have for worksite wellness.  Bottom line: stairs win.”

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Article adapted by MD Sports Weblog from original press release.
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Contact: Communications and Public Information
American College of Sports Medicine

The conclusions outlined in this news release are those of the researchers only, and should not be construed as an official statement of the American College of Sports Medicine.

Injuries occur to golfers of all ages and ability levels, and can significantly affect their golf game and daily life. Those who fail to warm up adequately appear to be putting themselves at greater risk of injury.

The survey involved 304 golfers, who revealed their golf activities, injury status and warm-up habits over a 12-month period. About a third of the golfers (111, or 36.5 percent) reported an injury, most frequently to the lower back, shoulder or elbow. Strains were by far the most commonly reported type of injury (37.8 percent). Other types of injuries included stiffness, inflammation, tendonitis, and sprains and, less commonly, pinched nerves, fractures, heel spurs and contusions or dislocations.

”Only a small percentage of golfers were shown to perform an appropriate warm-up prior to play or practice. The message isn’t getting across,” said Andrea Fradkin, lead author of the study.  “Golf professionals need to tell golfers to warm up, and not just hit balls.”

A full warm-up, she explained, consists of three components:
1. Aerobic exercise to increase muscle temperature
2. Sport-specific stretching (including stretching the shoulder, trunk, chest, lower back, hamstrings, forearm, and wrist)
3. Activity similar to the event, starting slowly and building in intensity (For golf, this might consist of air swings involving the club but not the ball)

Only three percent of golfers surveyed regularly performed two or more of the components, leaving them vulnerable to injury.

Fradkin and her colleagues noted that the frequency and types of injuries varied according to the golfers’ age and skill level. More experienced players—who play more often—tended to sustain more back injuries, while those with higher handicaps suffered more injuries to their hips, elbows and knees due to poor swing mechanics. Researchers noted that older golfers are likely to sustain more groin injuries due to a decrease in hip strength, and more knee and foot injuries due to degeneration of those joints.

According to Fradkin, this study underscored the results of her previous research into golfing injuries, while shedding new light. “This is the first study to look at the age, gender and handicap of injured golfers. Only two studies have looked retrospectively at injuries sustained over a 12-month period.”

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Article adapted by MD Sports Weblog from original press release.
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Contact: Communications and Public Information
American College of Sports Medicine

The conclusions outlined in this news release are those of the researchers only, and should not be construed as an official statement of the American College of Sports Medicine.

Golfers averaged more than 13,000 steps in walking to play 18 holes, and even those using carts logged more than 6,000 steps. Guidelines published by ACSM and others recommend walking 10,000 steps per day to maintain cardiovascular fitness and effectively control weight.

“This illustrates an enjoyable way to get the health benefits of walking,” said Cristina Sanders, lead researcher for the study, who presented the findings as part of her graduate work at the University of Colorado, Colorado Springs. “Some people play golf for 40 or 50 years, and it can be quite beneficial.” While previous studies have measured the energy expenditure of individual golfers, this study thought to be the first using pedometers.

Researchers asked golfers at three courses to wear a pedometer while they played 18 holes and noted their height, weight, and handicap. They also noted number of players in each subject’s group, whether he would walk or use a cart, and which tee box he played. After the round, researchers recorded how many steps each golfer walked.

“We had expected that golfers using a cart might take one-quarter as many steps as those who walked the course,” Sanders said. “We were surprised to find that, depending on the course, cart users logged up to half as many steps.” Measuring each course by GPS (global positioning satellite) allowed researchers to calculate minimum course distances, including tee-to-green, green-to-tee, and intermediate path point distances (bridges, paths around lakes, etc.) for each tee box on every hole. These minimum course distances averaged 25 percent longer than the published course playing distances.

Walking golfers and cart golfers took 13,145 +/- 1,736 steps and 6,280 +/- 1,428 steps, respectively. Interestingly, Sanders and her colleagues found no correlation between step count and the golfers’ height, handicap or tee box. Self-reported weight of walking golfers, though, averaged about 8.5 pounds less than that of golfers who used carts.

The golfers in Sanders’ study were all men. She proposed that future research include women, who often play from different tees.  Also of interest, she said, would be a large-scale look into golfers’ energy expenditure, accounting for the extra effort associated with carrying clubs or using pull carts.

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Article adapted by MD Sports Weblog from original press release.
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Contact: Communications and Public Information
American College of Sports Medicine