If you're looking for rubber arms, go no further than today's guest and his mind-bending 678+ innings pitched in 1884. He won 60 games that year (or 59--see his Wikipedia entry for more info) and totaled 309 victories in a fairly brief 12-season career.
Surprisingly, Hoss' amazing single-season win total doesn't appear in About.com's Top 10 of unbreakable baseball records, despite listing more reachable feats like Joe DiMaggio's 56-game hitting streak. This unfortunately reflects "modern" baseball's willingness to discard 19th century play as less meaningful. Yes, the game's changed since then, but this bias seems to reflect the emergence of supporting systems like radio, newspaper coverage, and statistical anaylsis.
Check out The Fleer Sticker Project's profile of this set for some awesome research on this set's 1975 and 1976 printings, plus a glimpse into artist Bob Laughlin's Inside Pitch card newsletter from the same era. I won't even give away the famous collector it pictures therein! (But remember, awesome.)