A strain may be a simple stretching of the muscle or tendon. It does not need to be a tear. Don't spread misinformation.
Jacktronic: Slow down Romeo... LOL. I'll have you know that I worked at several Physical Therapy clinics in the U.S. Army so it's not like I'm pulling this out of my ***. Your statement about the muscle/and or tendon being involved is correct. But it's more involved than just some "simple stretching". Heck if that were the case every time an athlete stretches before exercise they are straining muscles..