Swing Speed and Frequency Analysis

Frequency Analysis
The concept of utilizing electronic calibration or "frequency analysis" to measure flex was invented by Dr. Joe Braley and his son, Kim in the 1970's. The concept is straightforward. You clamp the butt of a shaft. You oscillate the shaft. A small electric eye or laser measures the oscillations in "cycles per minute" or CPM. You translate the CPM into a relative stiffness by locating a dot on a "frequency chart".

The frequency chart is an "x-y graph" in which the vertical axis is CPM and the horizontal axis is club length. The graph becomes the "chart" or "slope chart". The slope chart will have frequency lines running diagonally from the lower left to the upper right on a 45 degree angle determined by club length and CPM coordinates. The line connecting the dots is the "slope". ** (Graphic Illustration) More on slope later.

The result is a more precise way to discuss relative stiffness. The Braley method converts CPM into a numerical value, between 2 and 8. Each "flex" is divided into "subflexes" expressed in tenths. For example, if a "regular" is determined to be 5.0 and a "stiff" is determined to be a 6.0, then a 5.5 would be halfway between regular and stiff, a "firm" in today's nomenclature.