cracking ball

Question
my daughter uses a 6lb ball at 13yo because the others are too heavy due to muscle problems.  We used the ball once then it cracked after coming out the ball return. It wasp replaced then after using it only once again it cracked.  She does not throw it hard at all and I keep in the house and the air conditioner is keep at 78. Do you have any ideal why this is happening.

Answer
Elaine,

You haven't provided much information. Is the ball plastic? urethane? Whose idea was using the 6? I sure she wasn't able to put her fingers in a house ball. You may be too conservative in what your daughter can handle. Don't make assumptions. Many of the top female pro bowlers use 15 pound bowling balls, and some 16 pounders,.  and they are diminutive in stature.

Since the first indicator for me is body weight, I use 10% of a players body weight to begin examining what weight would be most effective. I'm assuming your daughter is more than 60 pounds at 13.

I'd suggest that ball fit is what allows bowlers to use bowling balls. You NEVER should use muscle to control a bowling ball. Spans and pitches are the keys to a modern fit. A less than effective fit will lead to using a clearly less effective weight bowling ball.

If the fingers of a 13 yo are drilled into a 6 lb'er, the stresses on the holes are more substantial than the tiny little holes that are usually in a 6. I'd suggest that so much material is removed when the ball is drilled, the voids created in the very light urethane foam inside the ball can't absorb the effect of the ball hitting the lane and hitting the pins, so the stress fractures the unsupported cover.

Thanks for the question. Good luck.