I'm 32. I have been following 5/3/1 for quite some time. I'm no beast but I have achieved a decent level of strength. I practice BJJ twice a week and fit in some Muay Thai once weekly.
In the past 6 months I have strained a lat doing chins, torn an adductor and tricep while rolling, and just tore my bicep throwing a left hook. Luckily the muscle tears were not too serious. There was some gnarly bruising but no complete tendon rupture. No surgery is needed.
The first thought that comes to my mind is that I am over training, but my energy levels are good and I am slowly but steadily getting stronger. I know shit happens but I am worried these are symptoms of a bigger problem. Any thoughts? 
Yeah being old crossed my mind. I suppose I'm in denial.