When I got out of the Army I went roughnecking in the oil fields. Also, my younger brother was roughnecking. One day he got caught up in the cathead and it ripped his shoulder out of place, tore his elbow ligaments, and broke his thumb completely over. He did what the doctor told him not to do, and did pushups every day plus several different exercises for his thump and shoulder. After a few months, he was back roughnecking. To this day you would not know what a serious injury he had, as not very many survive what roughnecks call "riding the cathead". Also, I have never seen a roughneck lifer(20 yrs or more) that wasn't crippled in an oil rig accident.