J. Harrington USA (Massachusetts) , May 07, 2012; 08:39 p.m.
Consider raising the camera's ISO. You'd likely need a lens that is 2.8 or faster. However, if you chose a zoom, that will be expensive.
Consider a 50MM 1.8. Not a zoom... but lets lots of light through.
Also check to see if all the lights are on in the gymnastics gym. I've been to indoor sports events where they only had on half the lights. After asking an employee to turn on more lights, pictures came out better.