THE LINE

If you're like most players, you've probably been tweaking your ground strokes by focusing on the top half of your body. The grip, the back-swing, the follow-through, and even the angle of your shoulders are probably just a few of the things you've tried to adjust in an effort to improve your groundstroke game.

However, greater gains can be made on your ground-strokes by focusing on the lower half of your body.

There's a technique you can use whenever you hit your ground strokes that, if done correctly, will give you perfect timing, balance, increased power and improve your consistency. Here's what to implement during your next practice session.

THE LINE

Next time you're on the court, imagine a Line running from the top of your head and continuing down through your body to the ground.

If you're standing straight upright, that imaginary Line will be positioned equally between both feet, but as you sway your torso to the left or the right, forward or backward (as happens when you play a point), your Line will move and position itself anew.
Wherever your Line meets the court will be your new center of balance.

Imagine a line running down from your head to your foot. 

In tennis, we often forget or are compromised when trying to achieve movement and balance during a point because we are under pressure and being rushed by our opponent. This pressure during points sometimes causes us to neglect our balance. 

Because our bio-mechanics starts in the ground, balance problems can lead to poor biomechanics.

The Contact Foot

Whenever you set up for a ground-stroke your task is to position this imaginary Line from your head over the foot you are using to generate inertia for the stroke, This foot is called your Contact Foot 

Positioning the Line over the Contact Foot will ensure a balanced, and consistent stroke every time and provide the maximum amount of power available from the ground (inertia).

At the time of contact, you should position the Line from the
head directly over the Contact Foot.

"The purpose of footwork is to create a Contact Foot"

The Line and the Contact Foot work together to
provide inertia, balance, and timing for your stroke

The Line and the Contact Foot coordination should be attempted on all strokes, including the Serve.

Serve

Avoid leaning into the court and "falling forward" when serving. Leaning forward prematurely does not give you extra power on the Serve as many believe, it only creates inconsistency, reduces your net clearance, and hinders your overall awareness of your target.

Instead, make sure the contact is directly above your Contact Foot (always the front foot) when you strike the ball, and allow yourself to cross the baseline only as a function of recovering your balance after the Serve. 

The Line and Ground are equally important when serving.
Here, the player will make contact above the Contact Foot
before entering the court. 

The Line is one of those techniques that you need to be aware of and integrate into every stroke you play. In the beginning, focus on the Line in practice so that it becomes a natural part of your game. Like everything new, The Line will take time to perfect but the effort is well worth the time you will spend on it.

Here is an article dealing specifically with the two-handed backhand ground-stroke.