Zombie arm refers to the non-dominant or non-hitting arm that is simply draped at your side, and looking, well… dead and unengaged when making any of your strokes, and is probably most obvious when hitting forehands.
Your non-hitting arm is essential to the efficiency of your racket preparation; it helps with your overall balance, as well as your ability to generate energy or power in your strokes.
How do you kill a zombie arm? Engage & eliminate! It’s a simple matter of engaging your non-hitting arm in various ways depending on the particular circumstance.
Having your off hand on the racket in the ready position and in between each stroke of the rally helps in your stroke preparation by making it easier to quickly find and change to the desired grip.
Eliminating the zombie arm on forehands… Step One is when you set up to hit your forehand, you have to make a conscious effort to engage your non-hitting arm by elevating that arm and holding it out in front of you, so that the back of your off hand and fingers are in plain view. This also helps with your balance as you set up to hit forehand… Step Two involves the elbow of your non-hitting arm. Imagine that your biggest rivals are crowding you, standing an inch away from you just to the side of your non-hitting arm. Now give them a friendly elbow when making your forehand stroke. This visualization and motion will help you clear your front side and allow you to make a full trunk rotation so you can properly finish your stroke.