It is not uncommon to hear about training programs that are “specific” to tennis. The term “specific” according to many of these coaches, usually means that the exercises that are prescribed involve the same muscles that are used in execution of the sport skills. But, this is far from what tennis training specificity should mean.
For example, the quadriceps femoris muscle group of the thigh is used to support the body in running, during stroke execution, in movement around the court, and generating power in the serve. Thus doing an exercise such as the squat is an excellent exercise to strengthen this muscle. The squat exercise, however, even though it strengthens the quadriceps muscles, it does not strengthen the quadriceps muscle in the same manner as it is used in executing a specific tennis stroke or movement on the court.
By doing the squat you develop strength which is of benefit in general conditioning. But the squat is not executed in exactly the same manner as in execution of groundstrokes, the serve, or even movement on the court. Even a simple change in body positioning or execution when doing the squat can change the type of muscular development received.
For example, when you squat, the weight is equally distributed over the feet. But when hitting ground strokes the weight is transferred onto the forward leg and the knee angle remains stable. In the serve, the weight is on the balls of the feet when the leg explosive actions are executed in the serve. In movement on the court the quadriceps undergoes explosive concentric contractions as well as eccentric contractions to stop movement and prepare for the stroke or movement, etc.
In order for the exercise to fall under the umbrella of tennis training specificity, it must fulfill one or more criteria as follows:
1) The exercise must duplicate a portion of the entire competitive skill. In other words, the movement in the training exercise must duplicate the neuromuscular movement involved in the execution of the particular skill. For example, if it is an exercise to strengthen the shoulder muscles that move the arm as it is used in a forehand stroke, then the movement in the strength exercise must duplicate the the beginning movement of the arm in execution of the forehand stroke.
2) The specialized strength exercise must involve the same range of motion as in the competitive skill. This means that the muscles must be strengthened in the same range of motion as they are used in the competitive skill. Another way of saying this is that you must develop strength as it is displayed in the stroke or movement.
For example, for quick movement on the court when taking two or more steps or when running to the ball, the rear leg is brought forward as quickly as possible from a behind-the-body position. Thus the strength or explosive exercise must begin with the leg behind the body when it is brought forward. When the leg gets in front of the body it is usually moving on momentum and strength is no longer needed in the middle or ending range of motion.
Most strength exercises that strengthen the hip flexor muscles, that are responsible for driving the swing leg forward, usually begin with the leg directly under the body and the thigh is raised to a 90° angle. This strengthens the hip flexors but not as they are used in fast movement in a running stride. For the exercise to be specific it must begin with the leg well behind the body.
3) The specialized strength exercise must involve the same type of muscular contraction as used in the execution of the competitive skill. To illustrate we can use the example of the squat exercise again. The squat is done at a moderate rate of speed and when a very heavy weight is used, you gain strength but the movement is slow. However, in the serve, the muscles undergo an explosive contraction to develop sufficient force to propel the body upward. The muscles also contract explosively in quick or reactive movements on the court.
The squat exercise for strength does not duplicate the explosive contraction involved. To develop the ability of the muscles to contract explosively, you must do exercises such as squat jumps and jumps out-of-squat. In essence, explosive plyometric jumps that duplicate the exact muscular involvement.
Many of today’s top players exhibit faster, quicker, and more explosive movements. Thus in order to be of most benefit, the training exercises must duplicate what the player must perform on the court. Merely playing the game is great for strategy and consistency, but it does not improve quickness or forcefulness of the hit. For this it is necessary to do supplementary training specific to the skill or portion of the skill involved.
You should launch your annual periodization plan with a general strength training to create the foundation and then move into a specialized training period in which most exercises duplicate what occurs in execution of specific skills. The body must be prepared infor the more intense training involved in specialized strength exercises.
In working with junior through professional tennis players, I have found that specialized strength exercises show the greatest improvement in the least amount of time. Because of the almost year-round playing done by most tennis players, there is not much time for supplementary training. But when the exercises duplicate what occurs in the execution of the skills, not only does it take less time but there is greater improvement. Specificity is the key to improvement after establishing a general strength base.
For more information on specificity of training and its application to the training of tennis players, see Build a Better Athlete and Explosive Tennis: The Forehand and Backhand, an e-book on CD and Explosive Plyometrics.