newbreedchicago explains knee reaps
http://www.sherdog.net/forums/f12/galvao-domination-794656/index4.html#post23599120
"Basically, it's applying heel hook pressure (which is illegal in the gi) without actually using your hands to heel hook someone.
Around the 1 minute mark, you can briefly see his opponent wrapping his outside leg under Galvao's leg and then bringing it around and over Galvao's leg. If Galvao's opponent's foot were to stay on Galvao's hip, he could maintain control without applying pressure on the knee. However, if Galvao's opponent were to remove his foot from the hip and take his leg (shin/calf) and bring it lower towards Galvao's knee, that could put a tremendous amount of pressure on the MCL, ACL, and meniscus; thereby breaking it without actually even doing a heel hook.
This would be even worse if Galvao were to actually try to base against it, and would obviously be bad as well Galvao went with it.
In otherwords, it's a heel hook, and recognized as such. Galvao was implying that it was a knee reap, and may have been (You can't tell from the footage). But either way, it something that's been called in many IBJJF tourneys.
The 50/50 isn't considered a knee reap only because the inside/out pressure applied on knee isn't as bad because the knee is given a chance and space to "buckle" without injurying it (in other words, there's more give). The opposite side, however, there isn't much give at all.
Hope this helps."
