OK. Here's some advice: don't squat in jeans. I had (note the operative word) some decent cut-off jeans acting as shorts for the hot weather. I decided that I fancied doing some squats and couldn't be bothered getting changed.
I did my usual warmup of 20, 30, 60Kg. All fine. 100x5, 120x5. Mo problems.
I went down at 140Kg and both legs ripped from knee to groin. I finished my 140x5 for three sets but my wife stood there looking for about thirty seconds when I came out of the stable, clearly wondering what deviant sexual perversions were the real explanation for the ripped shorts, before she cracked up laughing. I doubt I could have ripped them by hand even had I wished to.