Ps... Having seen your stroke pattern, that comment about abdominal bracing goes directly to you jenhaoyen. Do this cheesy video 5 times a week for three weeks and I bet you will see an improvement in the stability of your pivot - you might even like the look of your abs too.
[media]http://youtube.com/watch?v=sWjTnBmCHTY[/media]
hahahhaa i found this video 3 month before, i did it for once and i think i almost couldn't get up from the floor after doing that. HAHHAHA