And The Most Efficient Swim Stoke Is…

June 21, 2012 7:35 am 0 comments

Share This:

Subscribe:

Author:

Tags:

Swimmers, I mean top level swimmers, have never agreed about which of two arm movements is most efficient for freestyle swimming. In one corner, we have proponents of the paddle stroke, also known as the deep catch stroke, for which the arm is extended and which pulls the water like a boat paddle. In the other, we have proponents of the propeller stroke, also known as the sculling stroke, for which the arm is bent at the elbow and makes a slight S-shaped curve as it moves through the water. Now, thanks to researchers at Johns Hopkins University, we have our final answer: the deep catch stroke is more effective and more efficient than the sculling stroke. Finding that answer wasn’t easy. A Johns Hopkins news release reports that scientists from the department of engineering used high-precision laser scans and underwater videos of elite swimmers, then turned to animation software to change the shape of the static arm in such a way as to match the video sequence. The team then ran computer simulations to study the flow of fluid around the arm and the forces that acted upon the limb. Each simulation involved about 4 million degrees of freedom and required thousands of hours of computer processing time. Study author Rajat Miittal says his research disproves the long-held conviction of many swim coaches that the sculling stroke delivers more speed. “Sculling, in my view, is a swimming stroke that is based on an incomplete understanding of fluid mechanics,” Mittal said. “We found that lift is indeed a major component in thrust production for both strokes, and that certainly indicates that the arm does not behave simply like a paddle. However, the simulations also indicate that exaggerated sculling motions, which are designed to enhance and exploit lift, actually reduce both the lift and drag contributions to thrust. So, lift is in fact important, but not in the way envisioned by these early coaches who were trying to bring fluid mechanics into swimming.” Got that? Read more from Johns Hopkins.

Leave a Reply


Recent Posts

  • Pain Women's Health Men and Women Feel Pain Differently

    Men and Women Feel Pain Differently

    He hurts; she hurts, but she hurts differently–and probably more often. That’s the opinion of researchers at McGill University, who took a close look at the longstanding theory that pain is transmitted from the site of injury or inflammation through the nervous system using an immune system cell called microglia. Their research, yes, on mice, not humans, shows that this is only true in male mice. When the researchers altered the function of microglia in a variety of different ways, […]

    Read more →
  • Pain Do Knee Braces Do Anything Useful?

    Do Knee Braces Do Anything Useful?

    Do knee braces to anything useful? That’s the question put to New York Times health columnist Gretchen Reynolds. The answer, says Reynolds, is possibly, but it depends on the brace and on the injury. Reynolds quotes Dr. Robert A. Gallo, an associate professor of orthopedic sports medicine at Penn State Hershey Medical Center, saying that for each study that suggests wearing a knee brace can produce a clinical benefit in reducing pain or feelings of instability there usually is a counterstudy which demonstrates […]

    Read more →
  • Attitude Gear You Still Can’t Trust Your Pot Dealer

    You Still Can’t Trust Your Pot Dealer

    Drug dealers were never the most trustworthy of businesspeople, but that was usually because of a strategic disregard for the truth. Now comes a report claiming that many merchants of legal marijuana are selling pot whose potency labels are way off the mark, not for dishonest financial gain, but because they don’t know any better.  A news release from Johns Hopkins Medicine reports that researchers collected 75 different edible cannabis products — baked goods, beverages and candy/chocolates — representing 47 different […]

    Read more →
  • Pain Surgery For Arthritis Of The Knee? Think Again

    Surgery For Arthritis Of The Knee? Think Again

    Surgery for knee pain, at least knee pain caused by degenerative conditions like osteoarthritis, has no lasting benefits, according to researchers at the University of Southern Denmark. Worse, the operation exposes patients to serious health risks like deep vein thrombosis, infection, and pulmonary embolism. The New York Times reports that the Danish researchers reviewed nine randomized trials that involved 1,270 patients ages 50 to 62, and compared the benefits of surgery (for pain caused by degenerative conditions like osteoarthritis, not […]

    Read more →
  • Fitness Pain Extreme Exercise Without Training Can Poison Blood

    Extreme Exercise Without Training Can Poison Blood

    OK, it’s possible, but it’s not likely. When researchers at Monash University in Australia studied the biology of athletes who compete in extreme endurance events, like 24-hour marathons, they found endotoxins–gut bacteria that should be contained to intestines, in the athletes blood. No, it’s not good. HealthDay reports that the researchers took blood samples before and after the extreme events, and found that “exercise over a prolonged period of time causes the gut wall to change, allowing the naturally present bacteria, […]

    Read more →
  • Attitude Gear No, You Can’t Type Well On A Treadmill Desk

    No, You Can’t Type Well On A Treadmill Desk

    You’ve finally persuaded your boss to buy you a treadmill desk; congratulations. Now you have to persuade her that new research suggesting that walking while working seriously damages typing ability and mildly diminishes thinking ability is bogus. And it may be. After all, the research at Brigham Young University involved only 75 people, all of whom were randomly assigned a regular sit-down desk or a treadmill desk. Gretchen Reynolds reports in the New York Times that the subjects, none of […]

    Read more →
  • Attitude Pain Keeping Calm Under Stress May Keep Us Healthy

    Keeping Calm Under Stress May Keep Us Healthy

    Keeping cool in stressful situations could be good for your long-term health, if researchers at Penn State University have things right. The researchers studied two key markers of inflammation, as well as the emotions, of 872 people as those people responded to stressful situations such as arguments or being discriminated against over a period of eight consecutive days. As reported in a Penn State news release, the researchers found that those who failed to maintain positive moods such as cheerfulness […]

    Read more →
  • Attitude Pain What You Can’t Catch From a Toilet Seat

    What You Can’t Catch From a Toilet Seat

    Number one on the list of things you can’t catch from a toilet seat is- are you-ready?  Venereal disease. At least, according to Donald McNeil Jr., writing in the New York Times, there is no medical evidence that anyone has ever picked up a venereal disease from a toilet seat. Yet. McNeil recommends finding another explanation for your spouse, and by the way, good luck.  Number two on the list of things you won’t catch from a toilet seat is […]

    Read more →