Continuity mistake: At dinner, Robin starts eating the ice cream sundae and knocks the cherry off the top. In the next scene, when she passes the sundae to Mike, the cherry is back neatly on top and the sundae looks untouched. (00:12:50 - 00:13:30)
Continuity mistake: When Barney is at the apartment in his Top Gun costume, the position his helmet is in on the coffee table changes between shots. Sometimes the front of the helmet faces the camera, at other times it is sideways. (00:06:00)
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 ★