I mean you have to spend all game guarding the ball handler, being hit by screens, constantly moving laterally and being out in the open court where it's REALLY easy to pick up fouls if you touch them. I'm pretty short (5'10") so whenever I'm on court thats the role and really the best you can do is stay in front and if they get by hope that there is someone waiting. Reaching in and fouling isn't an option.