Model not moving as required

I’m very new to Blender and I have a character and I’m trying rig a walk animation using bone armature. I set it up. But the problem is that when I move the legs/arms, a part of the mesh sticks to a point and stretches out the object like so:


Here is the blend file: https://mega.co.nz/#!aVBlUKSJ!hKeiwHYjwIzSKo0Ai_YsAmgCgG1t1xkU3dVxn-0Odm4

Please tell me what’s wrong.

Thanks in advance.

it looks like a vertex is not properly weighted. go into weight paint mode and select the vertex group for that bone, and you’ll be able to see the area that is not properly weighted, then just paint over it so it matches the area around it.

I agree with Modron above… an alternative way to access that one vertex is to simply select it edit mode…
you should see then be able to see a box in the Right Hand Tool shelf called “Vertex Weights” that will tell you which bones that point is weighted too…
if there are some bones it should not be weighted too… just hit the ‘X’ to the right of the bone name and it no longer will be weighted to that bone…