In team sports the athletes were bonded by each other, there was an immense peer pressure to keep going. One dared not miss a practice for fear of letting his teammates down. Every time an athlete thought of getting back into bed in the morning he knew he would have to face the anger of his closest friends. But the sculler had to find motivation entirely within himself. No one else cared.
There's a great quote by Julius Irving that went, 'Being a professional is doing the things you love to do, on the days you don't feel like doing them.'
Few sports has as great a disparity between the time committed in practice and time actually spent in game or race conditions.