John Ritter looked like he hurt himself at times on Three's Company playing the character jack does anybody no if he got hurt or injured in real life ?

http://www.youtube.com/watch?v=YjitYbdq2BE
http://www.youtube.com/watch?v=yIg9w4gLf_Q
http://www.youtube.com/watch?v=dBIXYPy5fBw
http://www.youtube.com/watch?v=LbkQKEXYOjk
http://www.youtube.com/watch?v=LfAnTxVCMBo
http://www.youtube.com/watch?v=vBOaEHmFSkg
http://www.youtube.com/watch?v=vBOaEHmFSkg

I know he blacked out or suffered a concussion or something at one point while filming "A Night Not to Remember." I always tried to figure out what part.

The ironing board bit with Cindy and Jack looked very well done but poor John looks like they had to rehearse that a lot.