[maggief]

I watched a video clip on ESPN2. She missed half the volleys McEnroe fed her using kids tennis balls.

ref.

http://www.freerepublic.com/focus/f-chat/2775995/posts

Gamma Quick Kids 36 Foam Balls are specifically designed for kids learning to play tennis. This foam ball is smaller, softer, and has a lower bounce than the Gamma Revolution ball, making it easier for young kids to hit consistently. Quick Kids 36 Foam Balls were designed to conform to USTA QuickStart Tennis Program (36/60) standards for foam teaching balls on a 36 foot court. Ideal for ages 6 and under. Amazon.com

[montyspython]

Mac wasn’t using the foam ones, certainly looks the same but they are not. These are lower density balls used for the next level of practice.

My 5 year old was using them until now where she is using regulation balls for practice.