I agree wholeheartedly that there are a lot of variables that are in play when it comes to the bowling swing and how that swing affects ball velocity, rev rates & timing. It is also a fact that many, if not most bowlers do not use a full gravity-fed (free) swing. The more a swing deviates from this, the less will those fundamental
"pendulum" principles apply- and vice versa. My swing relies almost entirely on
gravity--from start to finish. It is an element of my game that took years to perfect.
Years ago, I attempted to develop more of a power game but discovered that it
created a lot of problems for me, so I abandoned it and returned to what works best for me. My good friend, who is also my age (65), uses quite a bit of acceleration in his swing, and that works best for him. We both compete at the same skill level
by using different approaches.
So, for those bowlers who fit more into my category, adhering to the principles
that I outlined above will, without a doubt, make a huge (positive) difference
in your accuracy, timing, and pin carry. I guarantee it.
While on the subject of pendulums, I would like to make sure that
some of its fundamental principles are understood. One of these principles involves
the relationship of ball speed to a bowler's (arm) length. Ball SPEED is completely independent of one's arm length. Put another way, a longer arm will generate
the exact same speed as a shorter arm . Ball speed in only dependent on one thing and one thing alone. It is only dependent on backswing height from the approach. If the ball descends from a height of say, 4 feet, it doesn't matter the length of the (pendulum) or arm from which it is suspended.
For the sake of clarification, I also want to clarify a point I made in my previous post as it relates to swing speed vs. pendulum (arm ) length. I stated that shorter ones move faster through the swing cycle. They do not. Shorter ones move at the same SPEED as longer ones if both are swinging through the
same DEGREE of arc . But because a shorter pendulum (arm) carves out less arc DISTANCE, it takes less TIME for the shorter pendulum to complete its swing than a longer one will. Again, pendulum speed depends only on the ball's height from the floor at the top of the backswing and nothing else. The TIME it takes for a longer arm to complete the same degree of swing will be LONGER because it is carving out a larger (but same DEGREE) of arc as the shorter arm.
So what this also means is that a bowler who DOES use a gravity fed swing (or very close) to it, will not experience a difference in TIMING by resorting to a shorter swing because the bowler's arm LENGTH does not change. Ball speed at release is different
than swing TIMING. (I am using "caps" just to point out the differences in terms).
So, for those who do deploy a gravity fed swing (or close to it), a longer arm will require slower feet to stay in "time" and vice versa. However, a longer arm will not affect ball speed (nor will a shorter arm). This depends only on how far the ball has to fall from the top of the swing(its height from the floor). Of course, there are many other factors not related to the pendulum itself that will certainly affect ball speed as well. Foot speed and
arm/body acceleration--applied at certain points, also affect ball speed, but I simply
focused on the effects on the bowling arm itself and its effects on timing, ball speed, and revs.
When it comes to revs, this too, gets complicated. Without giving revs the same breakdown as the pendulum, it's pretty apparent that the amount of revs is largely dependent on hand position and the amount of leverage (force) that is applied at the release, that are the 2 big factors in play here. But once again, it is much more than that. However, as it relates to armswing height, I agree that swing height is independent on the amount of revs a bowler can produce. Hand position and acceleration, applied at the precise point at release and in the right direction, is the biggest factor. But it's not the only factor, especially those who deploy the contemporary (wrist collapse) technique. For them,
it requires not only acceleration, but FINGER extension through the release that is
by necessity, different in terms of hand position and spine angles than the extension/spine angles used by bowlers who are more "old school" stroker
type players.