On this page you will find tennis videos of many types, from professional to little kids. Some will be for your amusement, others to help improve your tennis.
To see if you are holding the racquet correctly, use the index finger knuckle and heel pad and the 8 bevels on the handle as reference points. In this video a clear explaination of how to hold the racquet for various shots is provided.
From the Bollettieri Academy:
This is not a video about a great little player as much as it is about technique. It runs for 10 minutes but is well worth watching.
Del Potro has one of the biggest if not the biggest forehands in the game
Below are to tennis specific fitness videos. Very simple and effective