Moving Day - S2-E18
Visible crew/equipment: When Barney falls over in the truck, as he is lying on the floor you can see his mic on the back of his trousers and a wire connected to it. (00:16:35)
Moving Day - S2-E18
Continuity mistake: In the final scene when Barney is reading his top ten list, the piece of paper moves from his left to right hand and back in an instant between shots,.
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 ★