I don't think a martingale would be great for flyball - it's a collar designed so that dogs can't back out of their collar, therefore, it tightens which would probably make an excited flyball dog uncomfortable. I wouldn't get one for her if I were you, especially since that person didn't give you a reason as to why. The flyball collars with handles are good though if you don't want to use her regular collar. I'd use a harness though if it were my dog.