i had a bitch with the same problem, every time she ran hard both stoppers split, i,d let it heal for weeks, run her again and the same thing happened, i started taping her stoppers close to the leg and this worked for a while, i used surgical tape, but on a wet night the tape would open and it would split again, i got them removed but it didnt make any difference, the skin had become weak from constant splitting, her running days were over