Swing analyzer and golf club shaft selecting system

1. A swing analyzer capable of outputting information usable for analyzing a swing of a user swinging a golf club including a shaft extending in a longitudinal direction and a head portion provided at one end of said shaft, comprising:

a toe down strain gauge provided on the shaft of said golf club and capable of measuring strain in toe down direction of said shaft;

a built-in processing unit calculating an expected bending point value corresponding to a position of bending point of said shaft; and

a built-in display unit capable of displaying an output value from said built-in processing unit; wherein

said built-in processing unit calculates said expected bending point value based on a measured value of said toe down strain gauge at a first time point during a swing of the user and on a measured value of said toe down strain gauge at a second time point preceding said first time point;

said built-in processing unit stores in advance conversion data for converting said expected bending point value to recommended kick point output value;

said recommended kick point output value is an output value representing the expected bending point value of said shaft;

said built-in processing unit outputs said recommended kick point output value corresponding to said calculated expected bending point value to said built-in display unit; and

said toe down strain gauge is provided between a position of 304 mm and a position of 381 mm from said other end of said shaft.

2. A swing analyzer capable of outputting information usable for analyzing a swing of a user swinging a golf club including a shaft extending in a longitudinal direction and a head portion provided at one end of said shaft, comprising:

a toe down strain gauge provided on the shaft of said golf club and capable of measuring strain in toe down direction of said shaft;

a built-in processing unit calculating an expected bending point value corresponding to a position of bending point of said shaft; and

a built-in display unit capable of displaying an output value from said built-in processing unit; wherein

said built-in processing unit calculates said expected bending point value based on a measured value of said toe down strain gauge at a first time point during a swing of the user and on a measured value of said toe down strain gauge at a second time point preceding said first time point;

said built-in processing unit stores in advance conversion data for converting said expected bending point value to recommended kick point output value;

said recommended kick point output value is an output value representing the expected bending point value of said shaft;

said built-in processing unit outputs said recommended kick point output value corresponding to said calculated expected bending point value to said built-in display unit;

said toe down strain gauge continuously outputs measured values to said built-in processing unit;

said built-in processing unit detects a time point at which ratio of fluctuation of measured values continuously output from said toe down strain gauge exceeds a prescribed value, as an impact time point; and

said built-in processing unit sets said first time point between time points 10 ms before and 100 ms before said detected impact time point, and sets said second time point between time points 100 ms before and 200 ms before said detected impact time point.

3. A swing analyzer capable of outputting information usable for analyzing a swing of a user swinging a golf club including a shaft extending in a longitudinal direction and a head portion provided at one end of said shaft, comprising:

a toe down strain gauge provided on the shaft of said golf club and capable of measuring strain in toe down direction of said shaft;

a ball flying direction strain gauge capable of detecting strain of said shaft in a ball flying direction;

a built-in processing unit calculating an expected bending point value corresponding to a position of bending point of said shaft; and

a built-in display unit capable of displaying an output value from said built-in processing unit; wherein

said built-in processing unit calculates said expected bending point value based on a measured value of said toe down strain gauge at a first time point during a swing of the user and on a measured value of said toe down strain gauge at a second time point preceding said first time point;

said built-in processing unit stores in advance conversion data for converting said expected bending point value to recommended kick point output value;

said recommended kick point output value is an output value representing the expected bending point value of said shaft;

said built-in processing unit outputs said recommended kick point output value corresponding to said calculated expected bending point value to said built-in display unit;

said built-in processing unit calculates maximum amount of strain of said shaft based on a measured value of said ball flying direction strain gauge and on a measured value from said toe down strain gauge;

said built-in processing unit stores conversion data for converting the maximum amount of strain of said shaft to a swing tempo output value indicating swing tempo of the user; and

said built-in processing unit calculates said swing tempo output value based on the calculated maximum amount of strain, and said built-in display unit displays the calculated swing tempo output value.