September 26, 2003, Newsletter Issue #89: Sports Science and Tennis

Tip of the Week

TennisPro Magazine Article
Submitted by Joe Dinoffer

TOP TIPS on Sports Science
Entering the new Millennium means a lot of things, but it doesn’t mean that some of the leading tips from the end of the last Century aren’t still terrific and worth reviewing. The following tips have been compiled from the last five years of tennis teacher conferences from around the world as they were produced on “Coach Tennis America” AudioMagazine. This article features ideas from the sports science arena and, depending on the response, we can present other themes as well. Happy reading and let us know if you want more by contacting the USPTR TennisPro Magazine editor or myself at joe@oncourtoffcourt.com.

1. Todd Ellenbecker on racquets and injuries

Our first summary is nationally recognized physical therapist Todd Ellenbecker. Todd comments how changing frames or adapting a stroke to a different type of frame can cause very specific injuries. An example is that a wide-bodied frame tends to hit the ball further and therefore a player will often shorten their backswing or increase their topspin. This shortened backswing can cause a more compact and tense stroke. And, increasing topspin at a recreational level to keep the ball in often causes increased pronation that can cause elbow injury.

Todd also reviewed that torque equals force times the radius of the motion. Apply this to tennis: a longer racquet allows more torque, so the potential for injury increases. At the same time, a wide-bodied racquet stabilizes the racquet head and decreases the torque. Therefore, generally speaking, the most torque would be from a longer racquet with a slim frame design.

2. General tips on shock and vibration absorbers

Here are some more points on shock and vibration. Shock is the actual feeling of impact. For example, returning a Sampras serve with a full swing can create a shock force of up to 400 pounds. Vibration is defined as the lingering post contact sensation that does not cause injury. What does a vibration dampener do? First, a vibration dampener helps absorb high frequency string vibrations. Second, vibration dampeners affect the sound and the feel of hitting a tennis ball. But racquet head vibration is a low frequency sound vibration and is not affected at all by string dampeners. Therefore, vibration dampeners have nothing to do with solving tennis elbow problems. Vibration absorbers do not minimize shock; they just change the sensation and sound of the post impact vibration. And, stiffer and lighter rackets absorb shock less than the old, heavy wooden racquets. Here are seven ways to reduce shock:

a. Lower string tension by 10%.

b. Use a more flexible racquet.

c. Use a bigger racquet for a bigger sweet spot that results in less off-center hits.

d. Use a heavier racquet, which is perhaps the best way to reduce shock due to reduced racquet twisting on off-center hits.

e. Increase grip size to reduce shock since this reduces the effort needed to steady a twisting racquet on off-center hits.

f. Add a cushioned over grip.

g. Another source added that choking up slightly on the handle can decrease shock and also at the same time makes the racquet easier to swing. Of course, don’t give this advice to someone who just purchased an expensive extra long racquet! But it is a good tip for coaches who hit thousands of balls a day.

3. Jim Davis and Tom Martin on player strengths and weaknesses

Veteran Ohio teaching professionals Jim Davis and Tom Martin recently shared several interesting points that fit the category of Sports Psychology.

a. First, they assigned a player’s strengths and weaknesses to the following categories. The physical strengths and weaknesses they compared to a car, the emotional aspects to the driver, and the mental aspects to the fuel. Think about it, it makes a lot of sense.

b. They also shared that adults fall largely into the emotional side of learning, and that players of every level have their own magic need buttons. To prove this point, they commented that few adult players break down physically first. Observe recreational adult play and you’ll see players first break down mentally nearly every time. Press those magic need buttons and market adult programs with clinic themes like “improve your tennis from the neck up” or “strategy and tactics at the next level.”

c. As far as the psychology of learning is concerned they shared the Chinese proverb: “Tell me and I’ll forget, show me and I may remember, but involve me and I’ll retain it.”

d. Now, as far as dealing with students and helping them crystallize their tennis goals, Jim Davis and Tom Martin suggest asking students to write down answers to two questions. “If you stopped doing something today and it would help you play better, what would it be?” And “What is present in your game that, if you did more of it tomorrow, would help you win more points?” They emphasized that students should write these answers down because writing crystallizes the exact issues involved.

e. In that same session Tom Martin made a joke about choking. He described it as gargling peanut butter or driving a car with your emergency on. Picture it, did you ever see a player tighten up and hold back on their forehand groundstroke follow-through? Doesn’t it look like someone is driving a car and gradually applying the emergency brake until they come to a full stop?

4. Jack Groppel on video replay

Not too long ago, Dr. Jack Groppel presented the twelve qualities of what he described as the ideal performance state or IPS: players should be relaxed, calm, anxiety free, high energy, positive, enjoying, effortless, automatic, confident, alert, in control, and focused.

At the same presentation Jack presented the results of an unusual survey compiled from videotaping 100 players getting angry after an error on a tennis court. First of all, he said that when four of them saw their video footage they denied it was even them in the first place. The other ninety-six answered that they got angry only to show the people around them that they usually play better than they did on that missed shot. Interesting responses, aren’t they?

5. Dr. Michael Yessis on linkage and biomechanics

Now let’s move to an interview with sports kinesiologist Dr. Michael Yessis who had experience training top athletes in the former Soviet Union and now resides in Southern California. He shared with me some points regarding different possible axes of rotation during a tennis stroke. I found it particularly interesting as I watched a recent Senior Tour match between Jimmy Connors and John McEnroe. Everyone knows they are both examples of utilizing proper and efficient biomechanics.

Dr. Yessis related the axis of rotation to the radius of what is called the swing arm, and therefore to the resultant power achieved during a stroke. For example, on a properly hit semi-open stance forehand the front leg acts as the axis of rotation and maximizes the radius for hitting the open stance. The point he makes is that the longer the swing arm or swing radius, the more racket head speed is generated and therefore more power is efficiently transferred to the ball. This shouldn’t lead us to believe that our players should therefore always swing at their normal fast speeds to get more power. Rather, they can swing slower to improve their timing and, through proper biomechanics, would be able to hit with optimum efficient power.

To further explain this point, here are the four radius possibilities on a forehand:

a. First, the wrist would be the center of axis of rotation on a total emergency shot when reaching wide.

b. Second, the shoulder would be the axis of rotation when hitting on the run with little or no coiling of the trunk or hips.

c. Third, the spine would be the axis of rotation on an open stance forehand where the weight remains on the right leg for a right-handed player.

d. And, finally, the left leg for a right-handed player would become the axis of rotation on a closed stance forehand or on a semi-open stance forehand. But note that although the longest radius is produced when the opposite leg absorbs the weight transfer prior to contact, a fully sideways or closed stance also limits the range of angular momentum or possible uncoiling of the trunk and hips. Therefore the ideal groundstroke from an efficiency standpoint would be a semi-open stance forehand which optimizes both the radius length and coiling and uncoiling potential. (Note: This does not consider issues of moving forwards to the net after contact, which may benefit from a closed stance.)



6. Tom Gullickson on character attributes

Several years ago, renowned tennis coach Tom Gullickson presented the personal qualities of champions as six character attributes:

a. Commitment - Champions are focused on goals, some at a young age. They have dreams of being champions. Pete Sampras’ dream of winning Wimbledon and Jim Courier’s dream of winning the French Open are two examples.

b. Independence - Champions take responsibility, they don’t blame coaches or others for losses. They don’t look to the sidelines during matches. They have support teams, but the ultimate responsibility lies with them, and they know it.

c. Confidence and Self-belief - Champions have a great sense of themselves, they believe they can do it, especially when things are not going well.

d. Determination and Will - Champions are very determined and have great will power. Borg was unflappable, Chris Evert and Pete Sampras are quietly determined, John McEnroe and Jimmy Connors are more confrontational and expressive in showing their will. Champions do not give in. Champions develop resistance and when behind they fight until things turn around.

e. Competitive Spirit - Champions have a competitive spirit in everything they do. For example, Sampras finds a way to compete both against himself and within himself. Other players make it a personal fight.

f. Work Ethic - Champions prepare and plan well. They are organized. They know where they are going and how to get there. They are very concerned about their schedule and peak for big events.

Summary
I recently heard an analogy for sports that is 100% applicable to all members of the USPTR. It goes like this: A lot of people think play is only a button on a VCR. But for tennis coaches, it is our career. What an opportunity and what a blessing.

Note: “Coach Tennis America” AudioMagazine is produced by USPTR professional Joe Dinoffer and is available on ten 60-minute audiocassettes on a subscription basis. Contact Oncourt Offcourt at 800-752-7673 or 214-823-3078, or by email by visiting www.oncourtoffcourt.com . Website visitors can also listen to sample sections of "Coach Tennis America" as well as read more quick tips and articles. Joe Dinoffer has coached in over 50 countries around the world and has written five books and produced 17 videos for tennis teachers and the physical education industry. He is a frequent speaker at tennis teacher workshops and attends and presents at over 30 events each year. He lives (when not traveling) in Dallas, Texas with his wife and daughter.

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