Nothing like doing non-cycling exercise to make one realize that there are other muscles that don't get worked or worked as hard. Even just going jogging/running, my endurance is pretty sad compared to the distance I could do for the same effort on a bike. They are efficient machines, plus we get to coast! Can't coast when jogging, and moving the entirety of one's body weight (no matter how light or heavy) just takes more. I never like feeling tired or overworked hamstrings because they can stealthily cramp up on me (or threaten to) even if I've hydrated etc. I also get a good bit of power from them when on the bike, so no hams means no big guns for climbing, sprinting, or heavy 'dieseling' on the flats until they get better. Glad your weight held steady and went down after all!