I have had a problem with kicks since day one. It is so bad that I have difficulty getting much higher than mid-thigh on a roundhouse kick. And forget about a side kick. Anyway, Stadion's pamphlet described exactly what the feeling was that I have. Here are excerpts.
When the limit is reached, they feel that there is a "stop", accompanied by pain in the outside hip or upper thigh region that prevents them from opening their legs very wide...
The pain and limitation of the movement sideways in the side (straddle) split is caused by the spreading (abducting) the thighs without tilting the pelvis forward. This tilt unwinds capsular ligaments of the hip, among them the pubofemoral ligament that in a normal, non-flexed position would resist excessive abduction and would also, during straight abduction, push up the neck of the femur into the cartilage collar at the upper edge of the hip socket...
The forward tilt of the pelvis realigns the hip joint so its ligaments relax, the neck of the femur does not jam the cartilage at the upper edge of the socket, and the greater trochanter fits into a space behind the hip socket...
That's what it is, not anything tight on the inside, it's a dull thudding stop on the outside. Now, in the interest of economy I am going to try to get the proper advice here. What is this proper tilt? I've tried tilting forward in a fashion similar to, well, you know. But the effects where nominal if at all.
Or, if not able to explain here, is the $50 video by stadion worth it? They seem to know what the feeling is that I have and say they know how to fix it.
Here's a link that I got their info from.
http://www.stadion.com/pdf/free/flextest.pdf (PDF Format)