In my experience teaching timing, which I see as the number one most important aspect of bowling, I would say without seeing you bowl, your feet are getting to fast. Every time I deal with releasing late it is because the person's feet don't match their arm speed. I would first try to slow down your feet. If you watch the pros, you will see that the best take a surprising amount of tie to get to the foul line. You really can't be too slow. The other problem I have seen a lot of people have on this is that they are thinking about pulling through the ball. That is all well and good, but if you get too focused on that you keep pulling more and more which gets your release point farther and farther out onto the lane. The point of optimum leverage for your release is right next to your slide foot. I would say, try to visualize yourself setting down the ball and rolling it out onto the lane instead of throwing it or pulling through it.
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