(The information in this article was taken or adapted from the High Performance Coaching Program Study Guide.)
The five primary controls of the ball are depth, height, direction, speed, and spin. Mastery of these controls is essential to mastery of tennis stroke production.
Depth
One of the most important shot placement objectives is depth. Strokes that land near the baseline are much more difficult to return, limit the angles the opponent can play, and provide more time for a player to recover for the next shot. Players using excessive topspin must be careful to maintain depth during rallies.
Example—Remind players that the singles court is about three times longer than it is wide, so focusing on groundstroke depth is a safer strategy than focusing on side-to-side shot placement.
Height
One of the best ways to achieve depth of placement is to aim groundstrokes high over the net. Under the pressure of a match players who hit the ball flat may tend not to lift shots over the net, aiming near the tape, so their shots often lack the depth necessary to prevent attacking play by their opponents. (Keep in mind that about 70% of groundstroke errors go into the net.) Good players use topspin to achieve high net clearance and keep their shot out of the opponent’s hitting zone. They also use a higher ball to neutralize opponent’s natural aggression.
Example—Emphasize to players the benefits of varying the height of their shots.
Direction
The ability to change shot direction and the understanding of the tactical advantage, or percentages, of so doing is important to overall success. The following are general principles for shot direction:
- Crosscourt shots are easier and require less recovery but also have the greatest margin for error.
- Down-the-line shots are often more effective offensively but are more difficult. They must be stroked firmly to cancel out the lateral momentum of the ball and to avoid a higher net. These shots also require the athlete to recover a larger distance to stay in the middle of the opponent’s shot options.
Example—Emphasize to aggressive baseliners that an offensive down-the-line shot must be stroked aggressively for accuracy and must be followed up with aggressive recovery movements.
Speed
The speed at which the ball is stroked is another important variable the tennis player controls. Greater ball speeds place more pressure on an opponent by decreasing the time needed to get to and prepare for the shot. Ball speed also limits the opponent’s options and makes it more difficult for him or her to produce the shot. The negative aspect of ball speed is that the margin for error is lower, so it is more difficult to control the placement of the ball.
The speed and spin of the ball after a stroke are closely and inversely related, meaning more of one (speed) means less of the other (spin). The more direct the impact of the ball and the racket, the greater the ball speed will be leaving the racket, while the more glancing the collision is, the more spin the ball will have. Brody (1987) has an excellent discussion and several illustrations of how ball speed and spin affect shot accuracy and margins for error.
Example— Emphasize that margins for stroke errors are much larger for slow and moderate speed shots and that the margin for error decreases very rapidly at high stroke speeds.
Spin
Ball spin is clearly one of the most important factors related to ball control in tennis. Putting the correct spin on the ball can increase a shot’s margin for error and affect the bounce of the ball. All tennis shots are made with some ball spin; even “flat” serves and groundstrokes have some spin. However, it is the greater amounts of spin (1000 to 4000 rpm) produced by racket trajectory variations at impact that have the most dramatic effects on ball flight and bounce.
- Topspin. Topspin is created by upward motion of the racket through impact. For heavy topspin forehands, the path of the racket through impact is from low to high, usually between 40 and 50 degrees upward. Skilled players may use even steeper racket paths and some small closing of the racket face. Remember that the steeper the racket path, the lower the margin of error in contacting the ball and the less speed or pace the ball will have.
Example—Topspin strokes require greater effort to generate spin than slice strokes because the rotation of the ball must be reversed, so emphasize the use of vigorous upward stroke paths.
- Backspin or slice. Slice forehands and backhands are created by downward racket motion through impact. Research has shown that most slice strokes follow a 15- to 30-degree downward (high to low) path, again with only small amounts of opening of the racket face. A steeper downward path and clear open racket face are used for drop shots.
Example—Tell players to emphasize the “forward” of the forward and down trajectory of slice groundstrokes to maintain stroke speed. They should emphasize the downward trajectory only for the drop shot.
- Sidespin. Sideward motion of the racket through impact creates sidespin on the ball. Slice serves and inside-out forehands are good examples of sidespin. Research has shown that in slice serves the racket usually moves forward and to the sideline at 15 to 40 degrees from the center service line.
Example—As the player generates virtually all the sidespin on shots, emphasize the use of high racket speeds to the side through impact to generate speed and ensure adequate ball speed.
- Ball flight. The spin of the ball carries a small layer of air near the fuzzy surface of the ball. This rotation creates pressure differences called the “Magnus Effect”.
Example—Tell players that this additional force in the air makes balls curve in the direction of the spin. Topspin strokes curve downward because the front side of the ball is moving downward. Slice backhands have flatter trajectories than topspin because the Magnus force acts upward to reduce the effect of gravity.
- Ball bounce. The differences in the speed of the sides of a spinning ball affect the friction force during the bounce on the court.
Example—The effect of spin on the trajectory of the ball tends to dominate the effect of spin on the bounce. Groundstrokes hit with topspin tend to bounce higher than slices because topspin balls curve steeply down toward the court. Slice shots bounce lower than shots with topspin because of the very flat trajectory of these shots. The higher bounce of a drop shot is the only time you see an underspin bounce high, because of the trajectory of the shot.