In my opinion its Boxing, the sheer mental and physical exhaustion in a boxing ring is indescribable, even at the amateur level. It’s not just physical exhaustion, but also the mental concentration required in boxing. It’s the willingness to confront not only your opponent, but also your own fear. That reason, fear, as ESPN indirectly pointed out, is the reason more than any other that boxing is the most difficult sport. Nothing drains you and creates exhaustion like fear. Boxing is full of this intrigue, mystery, and raw competition. Boxing is also dangerous and detrimental to your health. Despite its flaws, boxing is the pinnacle when it comes to the true test of difficulty in athletic skill. This is why fighters fight for one word more than any other - respect. But I would like to know your opinion on which sport is the hardest.