After a while of lurking around here and reading some of the great advice that some members have given, I thought I'd go ahead and submit a video of my own weak link -- my squat -- for your feedback.
A bit of background: I became serious again about training this year after about a five-year period of fairly goalless lifting. During that time I dropped a lot of weight and strength, but this is coming back fairly quickly. I had been lifting fairly seriously for a few years before that and using a powerlifting-like template for a year or two, although I have never competed. I'm 187 cm/6'1.5" and currently only 79 kg/173 lb (in other words, a skinny mofo), but I've been gaining well and hope to get back to 85 kg/187 lb next spring. At that point, I would like to try to enter a competition here in my state, although powerlifting here in Germany isn't as big as elsewhere and it's sometimes hard to find an entry.
I'm currently running my third cycle of 5/3/1 as a means of getting back in the game. So far my progress has been OK; my deadlift is sitting right now at around 205-210 kg (451-462 lbs) and my bench press (my traditional weak link) is at 110 kg (242 lbs). My obvious weakness is my squat, which I estimate right now to be at around 120 kg (264 lbs). The discrepancy between my deadlift and my squat is glaring and leads me to believe that I might have some serious posterior chain/quad strength imbalances.
Attached is a video of my last warm-up set for today's squat workout, 5 reps @ 75 kg/165 lbs. I'm well aware that this is a light weight, but I'd still be eager to hear any feedback that you might have.
My initial reaction is that I'm coming forward on a couple of the reps and perhaps not sitting back enough... Quad weakness?
Thanks in advance for your tips!