well if it wasn't for him looking down I'd say the same thing but from the picture it looks like this is near the end of an event to which he's put pretty much everything he has and his form is suffering a bit. I know I do the same thing when i get really tired and after a couple of hours of bent elbows I just want to straighten them out to give my arm muscles a rest.

knee doesn't look that bad. I'm seeing a lot more riders ride with a bit more bend in the knees.