My 12U RHP in 6th grade is pitching 69 last night at practice (5'9" 134Lbs.)he is a premier player on a travel team - last October when he was 11 he was hitting 65 and constant at 64. Last August he was hitting 63 for tryouts and constant at 61. He grew from 5'3 to 5'8 during the last year. Now my other son at 13yrs RHP in 8th grade during his team's world series event was constant at 73 - when he made his highschool basbeall team at 14 yrs. he was hitting a constant at 76 - he just did tryouts for showcase teams and was clocked at 84 with a constant of 82. he also grew about 10 inches from 13 -15. (6'2" 148 lbs. and a sophomore in high school - a very young sophomore)maybe this will help?
I agree with what was written above, it is of no importance what speed a 9-10 yr.old is pitching - if they do not have good mechanics their arm will be useless by the time they are 13 and most likely 12, there are 4 boys that we play with that are getting physical therapy on their elbows this spring because of poor throwing mechanics, two of them are getting B-12 and saline injections into their ucl to help the inflamation and pain. Best prevention is a good instructor, the speed will come and in the words of an ex-pro instructor when asked if there was anything we could do to get more velocity - you can't do anythin, the maximum velocity was given to you when god made you - when it comes out it comes out.