This is probably a stupid question, that said I don't mind looking stupid if I learn from it. here it is.
Just got back into lifting, only two months of steady gym time now and tonight I decided to get closer to my max on bb squat. I was doing doubles, which I have never done before. The problem is I just tried to walk up my stairs and my knees literally buckled, really caught me off guard. Is this more than likely due to never using my nervous system to that extent or am I broken beyond repair?