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Humans Adapt Their Gait to Walk in the Laziest Way Possible

Humans are hard-wired to move in ways that require a minimal amount of energy. A new study in Current Biology from Simon Fraser University in Canada finds that while walking, people automatically adjust their gait to be energy efficient, adjusting their step width and frequency to do the least amount of work possible. 

The researchers, from Simon Fraser’s department of biomedical physiology and kinesiology, outfitted volunteers with robotic exoskeletons that forced them to adjust their gait by making them step more or less often than they would naturally as they walked on a treadmill. The participants adapted their step frequency to the optimum energy efficiency after just a few minutes of walking with their new gait, and did so even when the payoff was relatively small (less than 5 percent energy savings).

The robotic exoskeleton used in the study

As study co-author Max Donelan explains in a press release, “the nervous system subconsciously monitors energy use and continuously re-optimizes movement patterns in a constant quest to move as cheaply as possible."

So while you may go on a walk around the neighborhood hoping to get as much exercise as possible, your nervous system is actively making sure you do the least work you can. This makes a lot of sense when you consider that in the world of early humans, using less energy walking around normally might have left you a little extra energy in reserve to run away from a predator or catch up to your dinner. And, as the study points out, being able to constantly adjust your stride for efficiency might help people adapt to new tasks and different terrain, and avoid stride-inhibiting injuries. 

[h/t: Science News]

All images by Greg Ehlers

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Smiling Could Improve Your Athletic Performance—But Your Grins Can't Be Fake
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Athletes obviously enjoy breaking a sweat, but it’s not often that you’ll see one break into a smile while in the throes of competition. Yet that’s exactly what many coaches instruct them to do: Grinning mid-race has been said to relax muscles and boost physical performance. Recently, a group of researchers put this theory to the test, according to The New York Times. Their findings were published in the journal Psychology of Sport and Exercise.

Researchers from Ulster University in Northern Ireland and Swansea University in Wales instructed a group of 24 non-professional runners—both men and women—to shift between smiles and scowls while running on a treadmill. The volunteers were told that the experiment would measure how certain factors affected the amount of oxygen they used while jogging at various running speeds.

For the experiment’s first stage, runners wore face masks that measured their breathing. As they exercised until fatigue, researchers asked them to rate how they felt and report their coping strategies—for example, whether were they ignoring their pain or embracing it.

The study’s second segment required volunteers to engage in four individual runs, each lasting for six minutes. Mid-run, they were told to smile both genuinely and continuously, to scowl, to relax their torsos using a visualization technique, or to simply fall back on their usual endurance mindsets.

Smiles didn’t always improve runners’ performances. A few subjects picked up the pace while grimacing, possibly because these “game faces” made them ultra-determined to beat their personal records. But overall, runners with smiles were nearly 3 percent more efficient than normal. While seemingly insignificant, this difference is large enough to affect someone’s race performance, experts say.

Keeping in mind the study’s small size, the authors conclude that exercising while smiling might reduce muscular tension and thus amp up performance. But in order to gain this positive effect, athletes must beam genuinely. Fake smiles, like the kind you’ll see in school pictures, don’t work as many facial muscles, and therefore result in lower levels of relaxation.

Since it’s hard for anyone (let alone a focused athlete) to maintain an authentic smile during prolonged periods of strenuous activity, scientists suggest smiling near a race’s end, in 30-second intervals.

[h/t The New York Times]

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Marathon Running Won't Undo Poor Lifestyle Choices, Study Suggests
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Even marathon participants can't outrun an unhealthy lifestyle, according to a new study highlighted by The New York Times.

For years, expert opinion has been mixed on whether long-distance running helps or hurts hearts. In the 1970s, research suggested that marathon running and a heart-healthy diet would completely prevent atherosclerosis (a buildup of harmful plaque in the arteries). But since high-profile runners have died of heart attacks, scientists in the 1980s began to worry that running might actually harm the vital organ. Compounding this fear in recent years were studies suggesting that male endurance athletes exhibited more signs of heart scarring or plaques than their less-active counterparts.

Experts don't have a verdict quite yet, but researchers from the University of Minnesota and Stanford and their colleagues have some good news—running doesn't seem to harm athletes' hearts, but it's also not a panacea for heart disease. They figured this out by asking 50 longtime marathon runners, all male, with an average age of 59, to fill out questionnaires about their training, health history, and habits, and then examining them for signs of atherosclerosis.

Only 16 of the runners ended up having no plaque in their arteries, and the rest exhibited slight, moderate, or worrisome amounts. The men who had unhealthy hearts also had a history of smoking and high cholesterol. A grueling training regime seemed to have no effect on these levels.

Bottom line? Marathon running won't hurt your heart, but it's not a magic bullet for poor lifestyle choices.

[h/t The New York Times]

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