My son has played all kinds of sports since he was 5 years old. This post is not only about sports, it's about ALL aspects of life, schoolwork, chores, sports, etc... I've always told him, win or lose, succeed or fail, as long as you give your all, that's all you can do. I've preached never give up, try try again. Attitude is everything. I've tried every approach that I can think of to build his confidence. (FYI he has always been a good athlete, average to above average in everything he's ever played, sometimes he acknowledges his abilities, most of the time he doesn't) He will be 12 next month and still anytime that he fails, the first things out of his mouth are, I suck, I'll never be able to, I can't, There's no use, I'm terrible, etc.... I've used positive reinforcement until I'm blue in the face. Like I said this is not only about sports, it's just that with all the sports he plays these issues come up more often than just everyday failures or dissappointments of any other kind. I won't give up on trying to get him to believe in himself, but I'm open for any constructive suggestions. Thanks in advance for your responses.

Try showing him proof of all the things he's done well in. Does he have any awards? Trophies, or perfect scores on tests and papers? Telling him how good he is is great, but sometimes physical evidence can help too.