i have to agree with the posts above, some knee bend and some slide, some of the shots it looks like u had a full stop and almost went forward. i might be wrong with this...
since there is not shot of ur whole approach, meaning that u didnt show in the video ur starting position, i cant really tell if its wrong, but heres a guess.
My guess is at ur starting point, u hold the ball very low, maybe around the waist level. then u lift the ball (which is shown in the video) and then swing back with a very particular style.
i think the backswing is something personal, if u feel comfortable and can be stable with it, then why change it? what i suggest is to hold the ball little bit higher, so u dont have to lift the ball up and let it ball. so, instead of lifting, do little bit of push away and let it fall naturally. From the backswing to the release, i dont think u r muscling too much, but ur arm is not consistent, in a sense that sometimes the swing is close to the body, and sometimes it far away from it. try to fix that by paying more attention to the arm during the approach.
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When a house bowler misses the mark, misses the break point and strike, for many ppl its called a wallshot. When a pro does that its call adjustment
When a house bowler gets his finger stuck in the ball and fall on the lanes, for many ppl its called lame bowler. When a pro does that its called the Machuga flop! ha i like this one
This guy on youtube posts videos of the PBA
for ppl who dont watch TV or want to save the matches this will be great!
link! click me