Botched Set of Squats

[kinski]

So last night I'm having an awesome time squatting. The warm ups are feeling really light and I come out of the hole very quickly. I go to do my prescribed PR set of 5 (310 lbs) and decide to go for a sixth rep. I sink it just a hair lower than the previous reps, and the left side of the barbell bounces off the safety pin, causing me to relax for a split second on the left side. I dumbly decide to complete the rep, and halfway up I get a sharp pain in my left patella. This killed any of my volume sets, and today I get a sharp pain when walking, or when trying to extend my leg with any type of resistance.

I was wondering if you had seen any similar incidents in your years training and coaching, and if you had any insight into what this could be. The vague descriptions of knee injuries on Web MD aren't very helpful, and I would appreciate any contributions from experienced squatters.

For the record, these were high bar squats (couldn't get around that damn elbow tendinitis), and I have NEVER experienced any injuries from squats in the 6 months that I've been doing them weekly. 20 y/o male, 6'2', 180 lbs.

[Mark Rippetoe]

You tweaked some aspect of your patella. It will heal quickly. Train as the pain permits. Better squat technique would help.