International Bowling Pro Shop & Instructors Association​

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Entry Angle: Part 1

It’s crucial to raising strike percentage and average

I keep a pad of paper and a pen near my bed. I do this for two reasons: to write things down in the middle of the night so I don’t forget them in the morning, and more importantly, so I can purge these thoughts from my memory and get to sleep. I’ve learned that if I don’t do this I can’t stop thinking about it, but if I jot down the ideas, I feel confident that I’ve captured their essence and I can forget about them.

Of course, there have been times when I couldn’t read my own writing in the morning, so this gives me something else to worry about when I should be sleeping. Anyway, the other night at about 3 a.m., a thought occurred to me and I had to write it down. It involved the equation of a line drawn 6 degrees back from the pins up the lane.

Before I discuss the details of this equation, however, I want to address why this is important. This is the first article in a series about the importance of entry angles in bowling. The angle at which a bowling ball enters the strike pocket plays an enormous role in strike percentage, pin carry and, therefore in a bowler’s average.

You may have read that the USBC is taking a close look at bowling’s credibility relating to scoring. The USBC Sport Bowling program is one important aspect of that research. The significant technological improvements of bowling balls, lane oils, lane conditioners and lane machines over the last 20 years have played a key role in increasing the average amount of entry angle bowlers regularly can achieve.

The two charts – developed through testing and research by the USBC Equipment Specifications and Certification Department – illustrate why bowlers are continuously working to increase their entry angle through release (revolutions, axis rotation and ball speed) and bowling balls.

Figure 1 shows the influence entry angle plays in pin carry. The left side of the graph shows strike percentage. Across the bottom shows offset (distance from the center of the ball to the center of the headpin). The three colors reflect the degrees of entry angle.

For example, green represents 2 degrees, purple 4 degrees and red 6 degrees. Notice how much wider the red section (6 degrees) is at 90 percent strikes versus the green section (2 degrees) and even the purple section (4 degrees).

Sport Bowling tip of the month

Entering the strike pocket at the desired 6-degree entry angle can be accomplished by adjusting the four forces imparted to thw bowling ball in managing breakpoint. These include ball speed, revolutions, axis rotation and axis tilt.

Ball speed will be covered first in this series of USBC Coaching tips about how to increase entry angle. Subsequent tips will cover revolutions, axis rotation and axis tilt.

The most important aspect of watching the ball roll down the lane is noting where the ball starts to slow down. To attain ball reaction (hook), friction must be present. Proper ball speed is attained when the ball slows down on the right part of the lane to achieve the proper entry angle.

– Cary Pon is the Manager of Coach Development and Certification for the United States Bowling Congress Coaching program. The Silver level coach certified through USBC Coaching was listed among the “Top 100 coatches” for 2005 by Bowlers Journal International magazine. Pon also coaches at Bowling This Month’s Super School.

This shows what we all know; the pocket is “bigger” at a higher entry angle.

Figure 2 illustrates that as bowlers increase their degree of entry angle, they increase their average. There are other factors that determine your final average, but this chart makes it quite clear that if your entry angle goes up, so does your average.

The information provided in these two graphs clearly reflects the importance of increased entry angle when trying to increase your average. A 6-degree entry angle seems like a small amount, but it has a tremendous impact on scoring. Additionally, it doesn’t take a large increase to move up the chart; a change from 4 to 5 degrees is a big jump.

The next segment of this series will address how to use this line that I’ve drawn in my head, how to use it to play long and short oil patterns for optimum entry angle, how USBC Sport Bowling lane conditions impact entry angle and most importantly, how all of this will make you a smarter and better bowler.

-Neil Stremmel is the Technical Director for the USBC in Greedale, Wisconsin. He is a Mechanical Engineer (BSME from Bradley University in Peoria, illinois), an IBPSIA certified technician and a Master Computer Aided Tracking System instructor. Neil previously worked in the nuclear power and aerospace industries. He has served as a local ABC director and is a lifetime bowler who began working in a center at age 13.