Hitting a goddamn baseball? Are you kidding me? A RETARD can hit a goddamn baseball. Half the little leaguers in the country are batting .300 or better...yeah, really hard.
Most people's "proof" that hitting a baseball is so hard was Ted Williams saying it was hard. Yup, no vested interest in that answer, huh Ted? Way to glorify yourself. That's like Cael Sanderson saying wrestling is the most cerebral sport.
Running a marathon is the toughest thing on that list and nothing else is close. Running sucks.