Posts tagged with "Media release"

Splashdown: What’s’ the safest way to dive into a swimming pool?

August 3, 2022

Depending on the form and technique, diving into a swimming pool can either be poetry in motion or the aquatic equivalent of a car wreck. Now, scientists at Cornell University have used biomechanics to come up with a formula for safe diving, reports Study Finds.

After measuring the impact of head-first, hand-first, and feet-first diving, study authors put together a model for measuring the impact of different shapes as they plunge into a body of water.

For a novice, untrained diver, researchers say spinal cord and neck injuries are more likely to occur during a head-first dive of more than 26 feet. Meanwhile, collarbone injuries are more likely during a hand-first dive of roughly 40 feet, and knee injuries are likely when diving feet-first from more than 49 feet away from the water.

“Water is 1,000 times denser than air, so you are moving from a very dilute medium to a very dense medium, and you’re going to experience a huge impact,” says senior study author Sunghwan Jung, professor of Biological and Environmental Engineering in the College of Agriculture and Life Sciences, in a media release.

“Humans can choose how they dive, so we wanted to look at the effect of the  position of diving. We also wanted to come up with a more universal or general theory of how objects or different shape fronts dive into water, so we looked at the diving fronts of both humans in different postures and animals and measured the forces of impact of the different shapes.”

Study authors used a series of 3D-printed models depicting a near-life-sized human head and torso, torso and head with arms outstretched, and feet while diving. They also used models of a harbor porpoise head, a Northern gannet beak, and a basilisk lizard foot to conduct this research. The models allowed the research team to analyze the impact of curved, pointy, and flat shapes, respectively, on a body of water’s surface.

While throwing each model into water, scientists measured the forces acting on them and how they distributed over time. This approach facilitated the development of a theoretical model capable of describing the increase in force on the various shapes, and how those forces increased with the height of the dive.

Next, researchers plotted the maximum height and force impact human muscles, ligaments, and bones can withstand during a dive—calculating the probability of various injuries (collarbone, spine, and knee) at different heights and in different diving positions.

“In human biomechanics, there is a huge literature on the falling injury, especially in the elderly, and the sports injury, like concussions, but I don’t know of any other work on diving injuries,” Professor Jung explains.

Study authors hope their work helps people make safer diving choices. For example, a feet-first dive is safer from a higher perch.

Additionally, this project highlights how well-adapted certain plunge-diving animals are to withstanding and minimizing the impact of a dive. For instance, northern gannets have shallower beak angles. This unique feature helps them dive into water at up to 79 feet per second. Meanwhile, dolphins have shortened, fused cervical vertebrae, which support their head as they porpoise.

“As engineers, we are very good at making the airplane fly in the air. We are good at making a submarine move in the water, but crossing the interface, as you see in the animal world, is no easy task, and is something engineers are interested in—having a drone go from water to air or air to water, for example,” Professor Jung concludes. “So maybe this study can shed light on the new engineering design in the future that would allow systems to do this. For us, we try to understand the fundamental mechanics.”

The study is published in the journal, Science Advances.

 Research contact: @StudyFinds

Overeating doesn’t cause obesity? Scientists claim it’s all about what you’re eating, not how much

September 15, 2021

There may be no need to turn down that second portion and push back from the table. A team of scientists now says it’s  actually what you eat, not how much you eat that leads to obesity, Study Finds reports.

Their study finds processed food and rapidly digestible carbohydrates may be what’s really behind society’s growing waistline.

According to the Centers for Disease Control and Prevention (CDC), over 40% of American adults classify as obese. This places nearly half the population at higher risk of heart disease, stroke, and type 2 diabetes.

What’s more, the USDA’s current Dietary Guidelines for Americans for 2020 to 2025 maintains that losing weight “requires adults to reduce the number of calories they get from foods and beverages and increase the amount expended through physical activity.”

However, lead author Dr. David Ludwig, an endocrinologist at Boston Children’s Hospital and Professor at Harvard Medical School,  says that this age-old energy balance model for weight loss doesn’t actually work in a world full of highly palatable, heavily marketed, cheap processed foods. Indeed, he points out, despite years of public health messaging about eating less and exercising more, cases of obesity and obesity-related diseases continue to rise.

His team claims that its new carbohydrate-insulin model better explains the global trend towards obesity and weight gain, noting that the model even points to more effective and long-lasting weight loss strategies.

“During a growth spurt, for instance, adolescents may increase food intake by 1,000 calories a day. But does their overeating cause the growth spurt, or does the growth spurt cause the adolescent to get hungry and overeat?” asks Dr. Ludwig in a media release.

But if overeating is not the main cause of weight gain, what is? The real culprit is processed, rapidly digestible carbohydrates.

The study finds such foods also cause hormonal responses which alter an eater’s metabolism, drive fat storage, and lead to weight gain. When people consume carbohydrates, the body increases the amount of insulin it secretes. This signals fat cells to store more calories and leaves fewer calories for the body to use as muscle fuel.

As a result, the brain thinks the body isn’t getting enough energy to keep going and starts sending out the hunger signals. Moreover, the researchers say, a person’s metabolism can also slow down as the body tries to “conserve fuel. It’s a vicious cycle that leaves people thinking they’re still hungry and continuing to pile on more non-filling food.

Reducing consumption of the rapidly digestible carbohydrates that flooded the food supply during the low-fat diet era lessens the underlying drive to store body fat. As a result, people may lose weight with less hunger and struggle,” Dr. Ludwig says.

The findings appear in The American Journal of Clinical Nutrition.

Research contact: @StudyFinds