Continuity mistake: In 2-21 Something Borrowed, Lily's high school boyfriend, Scooter, reveals his name is Bill, but this episode in a flashback he tells Lily his name is Jeff. (00:03:47)
Continuity mistake: When Lily is talking about how much of a badass she used to be, it shows her meeting Scooter. He said his name was Jeff, but in season 9 Lily says that Scooter's real name is Bill. (00:03:40)
Answer: After running the marathon for Marshall with no training, he's allowed to ride the subway for free. While sat on the train, the muscles in his legs start to seize up after the marathon to the point it is painful to move his legs. This is why he can't move them. It's the same reason your body aches after a good session at the gym the day before.
Ssiscool ★