mine happened in a stupid fashion. i was lifting a garden bench, still in the box from lowes into the back of my pickup. i neglected to put the tailgate down and thought i could pitch fork toss it into the truck bed. i bent my knees a little and tried to create some verticle lift to tosser-in-there! only my left arm was under the box my right was over it for stability. as i thrust upward i heard and felt a lot of tearing. no pop. i knew from the pain right away that i did something serious. my bicep stayed flexed when my arm straightened under the load.
i now feel like i have no power in my left bicep, like it has been unplugged from the elec socket so to speak. the box probably weighed close to 100 lbs and i'm over 43, so i guess i was just introduced to my one-arm max lift. happened two weeks ago. painful lesson and i'm totally bummed to be out of crossfit commission. i did it in front of my wife and 13 yo daughter so i had to bite my tongue and act as if i was ok. my wife then drove me to the dr.
LESSON: put the tail gate down when you're old.