The Body Rotation System - Spinning vs. wobbling

A common phenomenon occurs after watching a good tennis performance. One's play seems to improve. True. Similarly, it is advised, that when playing golf in a foursome with inferior players, one should not watch any of the offending strokes, for ones play may actually degrade after the 200th poor swing you have seen.

So I do believe we can play a little better after an afternoon of watching the US Open. But what to look for? Certainly the tremendous power, the leaping and jumping, and flailing contortions are not so easy to copy, if not injurious to try.

One thing, however, does come to mind and can be easily observed and can be readily employed - the body rotation system/centeredness/spinning/wobbling.


Years ago, a baseball physicist named John White presented materials at a tennis conference in Carmel. He played with a whistling spinning top (the faster the top spun the more shrill the whistle, so one could hear how fast it spun). He demonstrated how when spinning with a vertical axis, the top tended to stay in one place (gyroscopic stability) but when knocked off its vertical axis it began to wobble (precession) and then moved around the table in an arc, quickly losing it's spinning velocity.

White applied the principles of gyroscopic stability to tennis, and in the early 1990's his model accurately described the games of Andre Agassi and Monica Seles. He spoke of a dual leg drive where the batter or tennis player didn't really step in, but rather drove the hip turn with both legs evenly weighted. He discussed the inertia of the arms and racquet and showed how short a simple quick swing enables the top to spin more quickly. And then he demonstrated how a centered, spinning action kept the head and eyes relatively still, whereas the wobble moved the head and eyes enormously.

Watch Barry Bonds or Roger Federer - the swings are not long but rather compact and quick. And the head stillness and resulting eye control are truly amazing. (White's book, Batting Basics, is very hard to find, and not carried by any publisher I know of, but is outstanding if you can find a copy somewhere.)

White's goals for the batter, and by extension the tennis player, were to hit the ball hard and hit the ball squarely. And he expected one to do just that by emulating a spinning top. He believed that five fundamental actions enabled just such a hard and square hit. They include body power, balance, good vision, flexibility, and bat control. Let me translate these five fundamentals into the tennis realm.


Federer's swing is compact and the head stillness and resulting eye control are truly amazing.

Body power - the intent is to maximize rotation using both legs. Here one emphasizes the large muscle groups, and is commonly known as "loading" in our tennis jargon.

Balance - a vertical spine, perfectly vertical that is, an even distribution of weight on both legs, a deep knee bend and a short soft hitting stride enhance gyroscopic stability. That is to say, stay low, stand tall, and turn rather than step in to the ball.

Good vision - the head is balanced atop this spinning machine, so the key here is to keep the hips still and level as they turn which then quiets the skull. This is where one can clearly observe either the wobbling of a spinning top off its vertical axis, or a perfectly centered "whirling" hit.

Flexibility - bend all the joints and relax the muscles, especially as regards the arm and racquet, as tension will restrict movement.

Bat (racquet) control - hold the racquet and arms close to the body. Delay the decision to swing, Tom Stow called this the "pause", and swing with a compact and quick delivery.

So the practical elements of the spinning top as applied to tennis include the following. The player does not really step in, but rather generates their turning momentum with the legs spread, balanced and equally weighted. The racquet and arms are held relatively close to the body on racquet preparation, the elbow is generally bent not straight. The strokes appear quick rather than fast, short rather than long - and this is Barry Bonds as well as Andre Agassi in spades.

When there is a slow motion replay of any of the players, find a spot in the background, maybe a fan in the stands, use this spot as a reference and notice clearly how little the head moves during the turn. Really just like centering clay on a potter's wheel. One cannot throw the pot until the clay is centered. Similarly, one cannot truly control the swing unless the body and head are centered - perfectly centered.

Now armed with this new perspective, monitor your centeredness, or the centeredness of others. I think you will notice a lot more wobbling than you might imagine.