Lots of resources out there on gate and movement. I for one think that everyone should see Rachel Page Elliott's Dog Steps VIDEO.

keeping in mind every dog has their own standard:

http://www.youtube.com/watch?v=_sjYUzKnax0#!

http://www.youtube.com/watch?v=iFPCYypAx-8

http://www.youtube.com/watch?v=iPBmW7nB0Qg

I was at an all breed show recently and had time to watch the Labradors (It has been awhile since I was able to sit ringside and watch). There were some really nice dogs and bitches. And then there were some that just made me shake my head. D & B (more so the B) with no length of upper arm - a few looked liked sausages on sticks. Many dogs who could not move correctly - no reach, no drive. I was quite sad to see so many entries like this - dogs who look like they couldn't last an hour or 2 in the field, much less a whole day. There was 1 bitch (who looked a bit older than the others) that was completely cow hocked when standing outside of the ring.

I was happy to see that these dogs were not put up as Winners or BOB. The winners and BOB each day were lovely examples of our breed.

But I have to wonder - where are we going when breeding dogs who look like some of the ones I saw....very sad indeed

I like Laura Dedering's comprehensive Lab diagrams at the link below:
http://www.cygnet-labs.com/folklaur/LabDiagrams.htm
See the Lab diagrams, the ones from Great Britain in particular.

According to the diagrams mentioned above, over angulation "may incline to cow or sickle hocks, produces poor hind action". Thank you Charlotte K. for posting this. I didn't know over angulation was the cause of cow hocks.

You are welcome. I do not think that overangulation always is the cause of cow hocks. It is often a LONG rear pastern or even just weak "couch potato" muscling that contributes to the the cow hocks. A dog with perfect angulation when crouching to spring for bait can also look cow hocked, temporarily. A cow hocked adolescent or bitch who has just weaned a litter can muscle up and have perfect angulation, even from the rear. True sickle hocks lack the working power of a springy cow hock in muscled haunches--the cow hocks can extend if not sickle hocks, too. Think how when you ride you can collect the horse with reins to put the weight on the rear of the horse to enhance the drive--kind of like a Cavalry horse maneuver. You can do it in a dog with a leash, to shift the weight back. It keeps the dog from pulling (young male dog!) and enhances the picture of the dog. I am not sure that my words are conveying what I'd like to say. No, I haven't bred a perfect rear--yet.