Originally Posted by Soianka
My daughter is 18, but this was in reference to my neice who is 10.
Thanks - I raised a tennis player daughter from age 4 to 18 and I have seen her through the 10U So Cal satellites up to Fed Cup competition for the Philippines. She is now on a D1 scholarship in the US.
Without the benefit of seeing your niece in competition, I will say that this is a very common problem for girls under 12 years old who are aggressive by nature but have not build a strong enough groundstrokes fundamentals to support their aggressive nature. Some of the posts here touched on drills that will help a young player to understand groundstrokes tempo and net clearance - all are great suggestions for a young player to develop her CONSISTENT rally balls. Without going into a long post, what I suggest for your niece is to FIRST find a coach that can properly drill into her the right way to get into the hitting position, have the backwing position in the right area, proper release of the cores and elbow through the groundstrokes with proper balance. Once these fundamentals are executed properly, someone needs to drill her (start with hand feeding) thousands of balls a day until the groundstrokes techniques are automatics. Once this is accomplish, then you niece can progress up to higher drills that incorporate footwork movements to simulate rally conditions.
Oh BTW, I wouldn't play her in tournaments until she can hit a 50 balls rally in practice with the right tempo, net clearance and balance finish on all 50 balls without missing.