The Oncourt Offcourt Angle Doctor guides players to feel the correct angle between the racquet and the hitting arm, and is fully adjustable for players of all sizes. The Angle Doctor immediately fixes many common problems including vollyers who drop their racquet head. It also helps players lengthen through contact on groundstrokes.
You've seen similar products on TV and in magazines, but the Angle Doctor is easier to use and much less expensive. As with all kinesthetic training aids, use the Angle Doctor for a few hits; then remove it and try to maintain the same racquet angle and feel. Occasionally a player will succeed immediately, but it is quite normal to need several practice sequences both with and without the Angle Doctor.
To use, simply wrap the arm band around your arm, just above the elbow, with the "D" ring on top of the bicep. Secure the thin Velcro strap to your racquet as shown. Since the racquet strap is adjustable on both ends, once you find the best position for a slice groundstroke or volley, you can keep that position. For topspin groundstrokes you will have to lengthen the strap so the arm is in a more extended position.