There are several reasons why this may have appeared to be a more effective strike than should be apparenty possible:
1. The platella(kneecap)is one of the hardest bones in the human body. A solid impact from this area has been proven to shatter lesser bones. In your case, if the impacts were to a tendon, this would have caused immediate tendon retention(tightening of the tendon). That would account for your symptoms.
2. Femoral nerve dysfunction. This is temorary inability to use, or fractional use of, the afflicted leg caused by trauma to the nerves in the thigh. One of the largest and most dense nerve clusters in the human body is located in the inner thigh. This is refered to as mononeuropathy of the sciatic nerves. This happens in the elderly after a serious fall and more commonly due to arthritis, as Sciatica, due to the presence of the cluster in the lower back/buttocks as well as upper legs.
Sig courtesy of that photo-matic magician limba
I went out the way that I fight. I went out on my shield. Thatís it. Done. --Chuck Liddell
My goal is to end my opponent --Carlos Condit