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Sport Science Myths Demystified - What Do The Experts Say?

May 25, 2008 12:25 PM

By Paul Roetert, Ph.D., Managing Director, High Performance

Did you know…

…Longer rackets can raise your service percentage?

With longer rackets, the contact point is raised a few inches, and that can result in more serves going in. According to Howard Brody, Ph.D., professor of Physics at the University of Pennsylvania, if you hit your serve hard and at maximum extension, the extra length can mean a higher service percentage.

…Your arm moves at about 2500 degrees per second during a serve?

According to Dr. Brody, that’s about the same as a bike traveling at 32 miles per hour or 417 times faster than the rotation of the second hand on your watch. We’re not sure what you do with this information, but figuring this kind of stuff out, keeps us out of trouble.

…You are better off using one swing speed for both your first and second serves?

When serving it is not the speed of the swing that should vary, but the amount of spin you put on the ball. For example, you can use less spin and aim more for the lines on your first serve. On your second serve, you can add more spin while keeping the racket head speed similar to that of your first serve. By having a consistent racket head speed, you will be able to hit your second serve with more accuracy and reduce your number of double faults.

…The average point on a hard-court lasts approximately 5-7 seconds and can as many as 4 changes of direction?

In tennis, every shot your opponent hits has a different speed, spin and placement. You are constantly changing direction in order to be properly set up for the next shot. Therefore, in order to improve court movement, it is critical to work on your quickness and agility. Drills such as the hexagon jump (see photo), alley hops and short sprints are good movement training drills to help you improve your quickness and agility on the court.

…The work/rest ratio in tennis is about 1:3?

It is important for tennis players to train in a way that is similar to actual tennis play. When training for tennis, keep in mind that the average point in tennis lasts less than 10 seconds, followed by 25-30 seconds of rest. This work rest cycle provides a similar stress to both the muscular and energy systems used in actual match play.

…Your shorts actually gain weight during a match?

Tennis great Don Budge always wore long pants during his matches and wondered if fellow Hall of Famer Bunny Austin had an advantage playing in shorts. Sure enough, Budge found that his pants had “gained” 7 pounds after weighing them before and after a match. Therefore, when playing tennis in the sun, it is important to wear light (weight and color), loose fitting clothing so that sweat can be properly evaporated and your body can cool itself. Light colored clothing will reflect the sun rather than absorb it like dark colored clothing. In addition, sweat soaked clothes do not allow for evaporation to take place so change to dry clothing whenever possible.

…Tennis builds mental toughness?

Two former Davis Cup team members, Richard Norris Williams and Karl Behr, survived the sinking of the Titanic in 1912. According to Bud Collins Modern Encyclopedia of Tennis, Williams dove from the deck of the ship, swam to a life boat and held on for six hours in near-freezing water until rescued. When rescued, a ship’s doctor advised amputation of the frozen legs. Williams refused amputation and one year later helped the U.S. to a 3-2 win over Great Britain in the 1913 Davis Cup World Final. This may serve as a reminder that when in doubt, get a second opinion.

...A tennis ball loses about half its speed in going from baseline to baseline?

This is because air resistance and the bounce slow the ball down. Dr. Howard Brody, a Professor of Physics at the University of Pennsylvania found that a serve hit at 120 mph ends up moving at only 60 mph by the time it gets to the other baseline. A groundstroke leaving the racket at 70 mph will only be moving at 35 mph when the opponent returns it from the opposite baseline.

...You have to swing your racket twice as hard to hit a topspin groundstroke as to hit a backspin stroke?

Dr. Brody says that when the ball coming toward you bounces, it acquires a great deal of topspin. To return the ball with backspin, all you must do is turn the ball velocity around since it is already spinning the way you want it to. To return the ball with topspin, you must not only turn its velocity around, you must also turn its spin around. This requires about twice as much racket head speed.

...Bananas will not resolve or prevent heat cramps, but a carbohydrate-electrolyte sports drink such as Gatorade or All Sport will?

In warm to hot conditions, most adult players will lose between 1.0 and 2.5 liters of sweat during each hour of competitive singles? Although sweat is mostly water, it also contains a fair amount of sodium and chloride. However, there is usually very little potassium in sweat. Dr. Mike Bergeron, assistant professor in the Department of Pediatrics at the Medical College of Georgia, found a strong relationship between heat-related muscle cramps and a high sodium loss, not potassium.

...One million new cases of skin cancer will be diagnosed this year.

According to Dr. Drew McCausland, a dermatologist from West Chester, PA, most forms of skin cancer have a better than 95% cure rate if detected and treated early. In order to prevent too much damage from the sun while playing, he recommends the following: avoid playing when the sun is at its highest (10am-2pm), use sunscreen with an SPF of at least 15 (don’t neglect areas such as the ears and lips), wear white or light-weight clothing that covers as much skin as possible, wear a hat or cap, turn your chair away from the sun at change-overs.

...A sunscreen with a SPF 15 will block out 93% of the sun’s damaging rays?

The power of a sunscreen can be calculated very simply. Take 100, divide it by the SPF (sunscreen protection factor) and subtract the answer from 100. Using a sunscreen with a SPF rating of 15:


Remember, no sunscreens are 100% protective, so apply generously before playing. The average adult requires about an ounce of sunscreen for adequate coverage.

...An estimated 5% of all teenagers suffer from some type of eating disorder?

Registered Dietitian, Teo McCormick believes that this is due to increased pressure in society for thinness as well as an increased emphasis placed on the relationship between body weight and athletic performance. Approximately 1 in 10 of those individuals who develop an eating disorder, consisting primarily of females, will die from one or more complications of the disorder. With these facts in mind, it is obvious that eating disorders should be considered a serious health threat to many young individuals. Eating disorders are both psychological and physiological and need to be addressed on both levels. Fortunately, if properly treated by trained health professionals, most complications are reversible.

...Breakfast is the most important meal of the day?

According to nutritionist Nancy Clark, people who eat breakfast tend to make wiser food choices the rest of the day and have an overall healthier diet than breakfast skippers. In addition, after a 10 to 12 hour fast your muscle energy levels are low and need to be replenished.

...Bagels are as good as sports energy bars?

Dr. David Pearson and colleagues at Ball State University, compared sport energy bars to bagels with a group of male cyclists. The results showed that none of the commercial sports energy bars tested offered any performance boost over bagels. No research is yet available to show that eating bagels makes you serve harder.

...Nasal strips don’t necessarily make you play better?

Although there may be some psychological benefits, several research studies presented at the American College of Sports Medicine Annual Meeting in 1997 showed no performance benefits using nasal strips during athletic activities. They can be very colorful however.

...You can burn almost 2000 calories in 3 hours of competitive tennis per week?

Dr. Jack Groppel, USTA Sport Science Committee Chair, notes that tennis combines the fat burning benefits of aerobic exercise with the health and strength building benefits of interval exercise. In addition, tennis provides great benefits for mental and emotional growth as well. So grab your friends and enjoy the benefits of tennis together, because tennis is the sport for a lifetime!

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