Joined: Jan 2009
Posts: 44,239
Likes: 6,494
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
I think you nailed it. Training might help, and working on fit might help, but that many hours of one activity has got to hurt to some degree. I find the last 25 miles of a century ride to be harder than the first 75 miles.