The Importance of the Arms in Tennis:

What is the role of the arms and shoulders in tennis?
The arms and the shoulders / chest deliver the power generated through the legs and trunk. The final adjustments for the stroke are made in these areas.

How should you train your arms to improve your game?
To train your arms to improve your game it is very, very important that you train symmetrically - in balance. The training of the front of the upper arm (biceps, brachialis) needs to be matched by the training of the back of the upper arm (triceps). The muscles that are frequently ignored are the latissimus dorsi. These muscles attach to the upper arm near the shoulder from the lower part of the back. All of your overhand strokes, including the serve need strength in these muscles. The most important component of your training program is muscular strength. This will enhance power and reduce the chances of injury. To strength train, you need to use fewer repetitions and have heavier weights. Gradual progression of the amount of weight is paramount. Some of the activities include biceps curl and triceps extension. Using dumbbells instead of bar bells allows you to use each arm separately. This is more like the way you will use the muscles.

What are the most common injuries to the arms and shoulders?
The most common injuries are rotator cuff tears and tennis elbow. Most soft tissue injuries occur in the muscles that counteract the stroke. In other words, in the shoulder after you have generated maximum force with the chest muscles and the triceps, you then have to slow the movement down with the biceps and the muscles of the back of the shoulder.