I don't know what do you mean by great athlete. To really succeed in professional sport one needs trully rare genes. I wouldn't advise anyone to aim for that sort of carreer unless they were identified from young age as elite level athletes. I am not talking now only about Jews. The rest of us can enjoy sport at amature level, it is fun and healthy
(except for boxing and the likes).
I don't think that what I say is a sterotype. The sterotype would be perhaps saying Jews are culturally averse to sport (which in the case of Charedim it is actually a fact). We don't have the gene pool of the Jamaicans nor the East African highlanders nor that of the Dalmatians etc.
When it comes to fighting sport like MMA and Boxing I especially don't want to see Jews get hurt for nothing. The odds of succeeding vs. ending up with brain damage, worn out joints, and steroidal side effects are such that a rational person should keep away from thiese sports.