Our daughter Amy is playing tennis since almost 2 years in Thailand. She is now 11 years old. Her weakness on court is her footwork and her posture while playing. Some years ago IMG Bolletieri Academy introduced a device called A.P belt system (AP stands for Athletic Performance) which helps the tennis student to strengthen his/her legs and develop the correct posture on the court. The AP belt system on their website costs $124.95 which I find pretty steep. Add shipping and the high import duties in Thailand, it would be just too much. But then I found on Amazon a very similar item called the "Pseudois Vertical Jump Trainer". The price is only $29.99 and with shipping and taxes it was only $67.20. We ordered one and we received it only 5 days later in the remotest part of northeastern Thailand. It looks very good and durable. We have made a short video of it on Amy's Tennis Training Channel on Youtube, here it is:. This post might be an inspiration for countless other parents of young aspiring tennis players.