I found this article on the internet......
• Let’s continue with our discussion of the four competitive zones of bowling. In our last dialogue about the subject, we gave a brief description of the four zones. In this article, we’re going to focus on transition and how bowlers have to move during competition between the four zones. Keep in mind these are common explanations and will differ with particular situations, but the idea can be used for most changes.
The majority of bowlers begin in Zones 1 or 2 for most conditions. However, with today’s modern equipment and high rev players, some may begin in Zone 3 and 4. With today’s equipment, it doesn’t take very long for the friction to develop at the front part of the lane and bowlers to begin moving to the left. Remember, the oil pattern is always changing.
Because the oil pattern changes, bowlers need a variety of ways to combat it; from changing angles, to changing equipment and your release. The bowlers begin moving their feet to the left, opening up their angles, and moving right through Zones, 1, 2, and 3. There’s a lot of friction in Zones 1, 2, and 3, so the only remaining fresh oil is in Lane 4 or outside Lane 1.
Now, bowlers face another problem. When the right-handed players start getting deep into Zone 3 and go into Zone 4, they begin to have an effect on the left-handed players. Remember, that most left-handed bowlers are also playing Zones 1and 2 on new oil, but are more focused on Lane 1 as opposed to the right-handed bowlers.
The options for the left-handed player are different, and this produces unusual changes; and before we know it, the laydown area for the right-handed player inches near the middle of the left-handed Zone 2. Very shortly, the laydown point for both the left and right handed bowler is going to be the same and strange things begin to occur.
When the laydown point for both right- and left-handers becomes the same, both bowlers face their own distinctive problem(s), and each side has to change their way of playing. You need to remember that the right-handers are influencing the lefties, but the early change on the left side of the lane is having an effect on how the right-handers have to play.
When the two routes come together, the left side can’t go farther inside where the right-handers have already played, and the right-handers must also fight the friction in the laydown areas of the lefties. What we now face is a lot of oil in the heads.
Many instructors call this a “lifesaver.†It’s found a considerable distance down lane and is usually the only place there is a significant amount of oil when competition drags on. When this occurs, the right- and left-handers must use their essential skills and knowledge to get the ball on the lane to carry.
Although we will speak of these skills in generalities, you must remember that most are based on how much friction is on the lanes. Let’s begin with Zone One.
This zone is the straightest of the zones. It usually requires the lowest axis rotation and the most direct angle. When playing this area, you might consider a ball that is low flaring that will aid in producing flat and level ball shapes. Your own style of bowling along with the level of friction will determine how much speed and loft you should use.
Zone 2 calls for a little more angle than Zone 1, both in relation to launch angle and at the back end. This calls for bowlers to use moderate axis rotation, in the 30 to 45 degree range.
Once again, your equipment selection in this zone will be fairly flexible and will be centered on the bowler’s style and the amount of oil. But, bowlers will usually not be required to use the most powerful equipment on the market in relationship to flare. Ball speed and loft will change with transition.
Zone 3 is the area where we begin to require additional change of course down lane for right-handed bowlers. Bowlers usually require higher degrees of axis rotation in this zone, and may want to consider higher flaring equipment more often in the zone. Lefties should consider going with more speed and loft to find enough oil to get through the friction created by the right-handers.
Zone 4 calls for the most degrees of axis rotation and launch angles. Depending on the quantity of friction, you may want to consider slowing down to help the ball generate movement down lane or speed up to get the ball through the dried-out heads. You may see high-flaring equipment with a number of surface changes and bowlers using loft as required to get the ball down the lanes. Left-handers will keep on using speed and loft to get to zone 4 down the lane.