Novice Squat Form Check

[mrflibble]

Hi Coach. I recently bought & read Starting Strength and am just into my second week of the novice program.

I figured it would be a good idea to have my squat form checked sooner rather than later so I can make sure I'm on the right track and pick up any mistakes before I ingrain poor habits.

This is from my 5th workout. It's only 140lbs but I'm new to low bar squats and started workout #1 quite light. Thanks in advance!

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

[Mark Rippetoe]

The reps change from pretty good but a little high to pretty bad but deep enough as the set progresses. Knees are sliding forward on the 5th rep.