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Racket Sports May Worsen Knee Arthritis

Press Release:

OAK BROOK, Ill. — Racket sports like tennis and racquetball appear to accelerate knee joint degeneration in overweight people with osteoarthritis, according to a study being presented at the annual meeting of the Radiological Society of North America (RSNA).

Knee joint osteoarthritis, a gradual wearing down of the protective cartilage that cushions the ends of the bones, is a major cause of pain and disability worldwide, affecting approximately 14 million people in the U.S. alone. Excess body weight is a major risk factor.

Physical activity offers a host of benefits for people who are overweight, but the wrong type of exercise could potentially damage knee joints and hasten the need for knee replacement surgery. The effects of different types of exercise on overweight people have seldom been studied with MRI, the most sensitive imaging method for assessing structural changes to the knee joint.

For the new study, researchers used high-powered MRI to assess the rate of degeneration of the knee joint in 415 overweight and/or obese patients, average age 59, drawn from the Osteoarthritis Initiative, a National Institutes of Health-supported study of individuals with mild to moderate osteoarthritis.

Study participants kept detailed records of their participation in six different types of physical activity, including ball sports, bicycling, jogging/running, elliptical trainer, racket sports and swimming. The researchers performed baseline MRIs and then measured changes in the patients’ knees over four years using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). A higher score indicates more degeneration.

Patients regularly participating in racket sports saw their overall WORMS score increase significantly, compared to patients regularly using the elliptical trainer over the study period. Surprisingly, the overall WORMS score also increased significantly in the racket sports group compared to the jogging/running group. Racket sports participants saw significantly greater degeneration in the medial tibial cartilage compartment, the compartment on the inside of the knee where arthritis often first appears.

Participants using the elliptical trainer showed the smallest changes in structural degeneration over four years.

“In our study, progression of overall knee joint degeneration was consistently higher in overweight and/or obese patients engaging in racket sports,” said the study’s lead author Silvia Schirò, M.D., from the University of California San Francisco and the University of Parma in Parma, Italy. “We also found that workouts using an elliptical trainer were associated with reduced progression of overall knee joint and cartilage defects. Moreover, our findings showed that when comparing different low impact activities with each other, such as bicycling, elliptical trainer and swimming, the elliptical trainer was associated with the lowest increase in WORMS sub-scores over 48 months.”

The more rapid degeneration of the knee joints in people who participated in racket sports is likely due to the high-speed lateral movements inherent to such sports, Dr. Schirò said. These movements can affect the femoral-tibia compartment, a structure in the knee made up of the femur condyle, the rounded end of the thighbone that helps it slide over the tibia, or shinbone, and the meniscus, the rubbery, C-shaped cartilage between the thighbone and the shinbone.

“A large lateral force imparted at the foot during side-to-side movements may be driving large knee adduction moments, a key feature in medial compartment disease, which imparts high compressive loads on the medial tibia and femoral condyle,” she said. “In support of this premise, the racket sports group showed elevated cartilage degeneration in the medial tibia.”

The researchers theorize that joint mechanics are impaired in overweight and obese individuals, with a harmful joint overload triggering increased contact stress on the meniscus. Damage to the meniscus compromises the protective cushion on the cartilage of the knee.

“High impact physical activity with elevated load and high shear forces may trigger and accelerate this process,” Dr. Schirò said. “Moreover, participants who played racket sports showed significantly more meniscal degeneration when compared to the remainder of the study group.”

The data suggests that overweight individuals who continue to play racket sports could slow degeneration in their knees by making modifications to their activities, such as switching to sports with less fast-paced and high shear loads like badminton or doubles tennis.

However, Dr. Schirò emphasized that the degenerative process is complex and individual joint mechanics are highly variable.

“It is possible that some individuals with sufficient strength and motor control may be able to safely play these sports,” she said. “Our data suggests that as a group, though, overweight and obese individuals who play racket sports are at higher risk for disease progression.”

Co-authors are Sarah C. Foreman, M.D., Magdalena Posadzy, M.D., Gabby B. Joseph, Nicola Sverzellati, M.D., Richard B. Souza, Ph.D., Charles E. McCulloch, Michael C. Nevitt, Ph.D., and Thomas M. Link, M.D., Ph.D.

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Study reveals physical demands of two-hour marathon

Some of the elites runners were tested at Exeter Arena

Press Release:

Elite runners need a specific combination of physiological abilities to have any chance of running a sub-two-hour marathon, new research shows.

The study is based on detailed testing of athletes who took part in Nike’s Breaking2 project – an ambitious bid to break the two-hour barrier.

Professor Andrew Jones, of the University of Exeter, said the findings reveal that elite marathon runners must have a “perfect balance” of VO2 max (rate of oxygen uptake), efficiency of movement and a high “lactate turn point” (above which the body experiences more fatigue).

The VO2 measured among elite runners shows they can take in oxygen twice as fast at marathon pace as a “normal” person of the same age could while sprinting flat-out.

“Some of the results – particularly the VO2 max – were not actually as high as we expected,” Professor Jones said.

“Instead, what we see in the physiology of these runners is a perfect balance of characteristics for marathon performance.

“The requirements of a two-hour marathon have been extensively debated, but the actual physiological demands have never been reported before.”

The runners in the study included Eliud Kipchoge, who took part in Breaking2 – falling just short of the two-hour target – but later achieving the goal in 1:59:40.2 in the Ineos 1:59 challenge.

Based on outdoor running tests on 16 athletes in the selection stage of Breaking2, the study found that a 59kg runner would need to take in about four litres of oxygen per minute (or 67ml per kg of weight per minute) to maintain two-hour marathon pace (21.1 km/h).

“To run for two hours at this speed, athletes must maintain what we call ‘steady-state’ VO2,” Professor Jones said.

“This means they meet their entire energy needs aerobically (from oxygen) – rather than relying on anaerobic respiration, which depletes carbohydrate stores in the muscles and leads to more rapid fatigue.”

In addition to VO2 max, the second key characteristic is running “economy”, meaning the body must use oxygen efficiently – both internally and through an effective running action.

The third trait, lactate turn point, is the percentage of VO2 max a runner can sustain before anaerobic respiration begins.

“If and when this happens, carbohydrates in the muscles are used at a high rate, depleting glycogen stores,” Professor Jones explained.

“At this point – which many marathon runners may know as ‘the wall’ – the body has to switch to burning fat, which is less efficient and ultimately means the runner slows down.

“The runners we studied – 15 of the 16 from East Africa – seem to know intuitively how to run just below their ‘critical speed’, close to the ‘lactate turn point’ but never exceeding it.

“This is especially challenging because – even for elite runners – the turn point drops slightly over the course of a marathon.

“Having said that, we suspect that the very best runners in this group, especially Eliud Kipchoge, show remarkable fatigue resistance.”

The testing, conducted in Exeter and at Nike’s performance centre in Oregon, USA, provided a surprising experience for a group of amateur runners in the UK.

“We tested 11 of the 16 runners at Exeter Arena a few years ago,” Professor Jones said.

“Some local runners were there at the time, and it was a real eye-opener for them when a group of the world’s best athletes turned up.

“The elite runners were great – they even joined in with the local runners and helped to pace their training.”

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Former NFL players may not suffer more severe cognitive impairment than others, study indicates

Press Release:

DALLAS – Nov. 11, 2020 – Even though repeated hits to the head are common in professional sports, the long-term effects of concussions are still poorly understood. While many believe that professional athletes who experience multiple concussions will end up with severe cognitive impairment later in life, a UT Southwestern study suggests that may not necessarily be the case.

The preliminary study, published in Cognitive and Behavioral Neurology, looked at a small cohort of retired professional football players who had a history of concussions and were diagnosed with mild cognitive impairment (MCI), a known risk factor for Alzheimer’s disease. The 10 retired athletes, plus 10 nonathletes, were given a battery of cognitive tests to assess their verbal memory, learning, and language skills. The nonathletes also had MCI but no history of traumatic brain injury.

“For the most part, the athletes had a similar cognitive profile to the nonathletes,” says Nyaz Didehbani, Ph.D., assistant professor in the department of psychiatry and the study’s corresponding first author.” But they did score lower on a couple of items, more specifically on our naming test, which has been showing up in a number of our studies. A consistent complaint from many of our athletes includes word-finding and naming difficulties.”

Name recall, or the ability to see something and name it, diminishes quite frequently with normal aging, says Munro Cullum, Ph.D., vice chair and chief of the division of psychology in the department of psychiatry and the study’s senior author. “It’s not that they have lost the ability, but rather have a reduced ability to quickly retrieve words when they’re shown a picture.”

Despite differences in their ability to name recall, the retired football players scored similarly to the nonathletes on verbal memory and learning. This is in contrast to findings from other studies in which a history of concussions in athletes has been found to also affect these areas.

“Overall, the study is suggestive that just because you’ve had a history of multiple concussions, it doesn’t mean you will develop a neurodegenerative change or problems later in life,” says Cullum.

The retired NFL players range in age from 64 to 77 and played anywhere from six to 14 years in the NFL. The nonathletes were selected from an Alzheimer’s Disease Research Center database at UT Southwestern. The groups were similar in age, sex, race, and education.

One clue as to why multiple concussions appear to have a selective effect on name recall may lie within the brain itself. Imaging from other studies done by the UT Southwestern group on these athletes demonstrated an interesting phenomenon.

“We had an imaging finding of an abnormality in the white matter deep in the part of the brain where word retrieval is thought to occur,” Cullum says. These studies found that changes in white matter in retired athletes with a history of concussions were linked to poorer performance in naming, though it is still unclear why only this area of the brain appears to be affected. The authors are designing experiments to learn more.

Although the degree of the cognitive impairment wasn’t much worse in retired athletes with MCI, this study provides only a small picture of the issue. There is evidence from other studies that exposure to repeated concussions can lead to earlier onset of MCI and that cognitive impairment may be higher in retired athletes.

The team at UT Southwestern is working to resolve these conflicting results from other studies by following a larger cohort of retired athletes over time. They are seeking to investigate the long-term effects of concussion on the brain by assessing how cognition changes over time, the rates at which it changes, and the effects of comorbidities (the presence of other illnesses) and psychological factors in athletes with MCI and a history of head injuries.

Within the context of this study, the authors are also interested in looking at different ways to evaluate cognition to better understand the state of neurodegenerative changes in athletes and to determine if the link between concussion and MCI is direct or correlative.

“Their being professional athletes does not necessitate automatically falling into this doom-and-gloom category that the cognitive impairment will progress and worsen,” says Didehbani. “Those cases are really just a subset, just like with the normal population.”

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For young athletes, inadequate sleep leads to decreased performance

Press Release:

November 9, 2020 – Most young athletes don’t get enough sleep – and that may significantly affect their sports performance, according to a paper in the November issue of Current Sports Medicine Reports, official journal of the American College of Sports Medicine (ACSM). The journal is published in the Lippincott portfolio by Wolters Kluwer.

“There’s growing evidence to suggest that youth athletes don’t get required amount of sleep, and that this negatively affects their performance,” comments Mark F. Riederer, MD, of C.S. Mott Children’s Hospital, University of Michigan, Ann Arbor, author of the new review. He believes that the trend toward more-intensive training might contribute to a lack of adequate sleep in in young athletes.

Rested and ready? Youth athletes need more sleep to do their best

Faced with competing demands including school, sports, and social life, young athletes tend to put off sleep in favor of other activities. Generally, the evidence suggests that they don’t meet recommended guidelines for sleep duration: 9 to 12 hours for children aged 6 to 12 years and 8 to 10 hours for adolescents aged 13 to 18 years. For example, one study found that more than 90 percent of teen gymnasts get less than 8 hours of sleep per night.

Most studies find that young athletes get less sleep than non-athletes; they may sleep longer on the weekends, trying to make up their “sleep debt.” The evidence suggests that young female athletes sleep less than their male counterparts. However, elite-level teen athletes of both sexes seem to get more sleep – possibly related to higher sleep need due to higher training loads.

Although studies vary, the evidence suggests that getting less-than-recommended sleep leads to decreased performance on the playing field. Some papers report that inadequate sleep has significant effects on reaction time, strength, speed, cognitive learning, and decision-making.

“[S]tudies consistently demonstrate that lack of recommended sleep results in poor sense of well-being, increased perceived training load, and poor placement in competitions,” Dr. Riederer writes. Sleep deficits may also place young athletes at risk for injury and illness.

Other recent findings include:

Studies of napping and other sleep interventions show inconsistent effects on athletic performance.
Young athletes with symptoms of insomnia may be at increased risk of burnout, along with a higher risk of dropping out of their sport due to injury.
Levels of the stress hormone cortisol are increased after competitive matches, leading to reduced sleep time and quality.
Poor sleep may be linked to obstructive sleep apnea among college football linemen.
Inadequate sleep might be a risk factor for bony stress injuries (such as stress fractures).
Although it has been suggested that using smartphones or other electronic devices before bed can lead to impairments of sleep or athletic performance, one recent study found no such effects.

“The message for young athletes is, getting recommended sleep can improve your performance,” Dr. Riederer comments. He notes that an emphasis on increasing training workload to improve skill and performance may adversely affect young athletes in other ways.

“Trends like early-morning training schedules, two-a-day practices, and late night practices and competitions come at the expense of good sleep habits – as well as leaving kids less time to socialize and do homework,” Dr. Riederer adds. “We need to ensure our youth athletes are getting adequate amounts of sleep, and there is evidence to support this claim.”

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Concussion: How the NFL came to shape the issue that plagued it

Press Release:

ANN ARBOR — Players kneeling during the national anthem is the most recent NFL controversy, but certainly not the first nor the biggest.

Concussion has dogged the NFL since the 1990s, and its initial response — avoidance and superficial gestures to mollify critics — damaged its public image. However, in recent years, the league has repositioned itself as a leader in concussion prevention and research, a new University of Michigan study shows.

The study found that the NFL’s newly proactive stance shows how a large organization can wrest control of and shape the very issue that haunted it.

“They said, ‘We’ll change, but it’s going to be on our terms. We want to be the leaders in concussion,'” said study author Kathryn Heinze, U-M assistant professor of kinesiology. “They said, ‘If we have to change, we’ll take credit. We’ll create the funding. We’ll create the partnerships with other organizations. We’ll work to pass new laws.’ When they finally realized they had to do something they realized they had to be the leaders.”

The NFL is likely one of the few organizations that could achieve this, largely because it’s so influential, Heinze said. Still, the league would have been better off implementing these changes years earlier.

“There’s a lesson here around getting ahead of these changes sooner and avoiding the intermediate stages where organizations resist or avoid change,” Heinze said. “They may have avoided some of those lawsuits, or the Judiciary Hearings on concussion, yet we still see this path very often.”

The study’s purpose wasn’t to judge the NFL’s handling of concussion, but rather to look at how one organization reacted to demands for institutional change. Heinze stressed that findings in no way suggest that the NFL has done all it can to protect players from concussion, only that it has now adopted a leadership role in addressing the problem.

Researchers looked at the NFL’s response to concussion from the early 1990s to 2015. From the 1990s to 2008, the NFL either dismissed concussion as a non-issue or made superficial gestures that didn’t yield substantial change, a strategy called decoupling. Later the league made significant but incremental changes that didn’t yield fundamental shifts.

For instance, in 1994 the league created a concussion study committee, but most members were affiliated with the league and weren’t concussion experts. Later, it appointed an independent director, but 10 of the 14 members remained tied to the league in some way.

However, from 2009 to 2015, the league responded to intense, coercive internal and external pressure by making fundamental organizational shifts, the study says. For instance, it abolished the existing, much-criticized concussion committee and established the Head, Neck and Spine committee, which consisted only of concussion experts unaffiliated with the NFL.

More importantly, Heinze said, the league changed its ideology and also engaged in advocacy, which enabled it to shape the agenda regarding the concussion issue. It finally acknowledged the long-term effects of concussion. It served as a broker, forming partnerships with academia, government and business. It was instrumental in passing a law in 50 states to protect youth athletes who experience concussion; only four states passed this law prior to NFL involvement.

Heinze said researchers were surprised by how dramatically an organization’s position could shift in a relatively short time.

“I know it took a while, but once they decided to go in that direction, they attacked it from multiple perspectives,” she said.

Whether other large organizations model the NFL and take a leadership role on controversial issues remains to be seen. Heinze said the NFL’s initial response of denial and avoidance is much more typical.