Visible crew/equipment: When Marshall runs through the smoke towards The Limo, you can see the fog machine in front of Barney's head used to create the "smoke" effect. (00:17:40)
Nothing Good Happens After 2 A.M. - S1-E18
Visible crew/equipment: When Robin hands Ted the glass of wine, you can see set lights reflected in the glass. (00:10:55)
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)
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 ★