[TIPS] The Flexibility Of Shafts

There are a variety of club shafts with diverse flexibilities for golfers. Each individual has his/her own swing’s power and tempo distinctly, therefore a golfer should take times to consider between a flexible shaft or a stiff one to bring out the best shots of accuracy and strength.
On each shaft, there is a letter code standing for its flexibility. The most common letters are L, A, R, S and X, with the flexibilities decrease by this order.
“L”: stands for “ladies flex”
“A” or “M”: denotes “amateur” or “medium flex” (can also be designated “AM”, “A/M” or Senior”)
“R”: represents “regular flex”
“S”: stands for “stiff flex” (or “Firm”)
“X”: represents “extra stiff flex” (or “Tour”)
When swinging, the shaft will be bent under the impact and affect the point of contact of the clubface with the ball, which will affect the three most important factors of a stroke: accuracy, trajectory and distance. Therefore, using inappropriate shafts, too stiff or too flexible, will make the shots not so good as expected.

Source: ThoughtCo.com

In the case of striking with a too stiff shaft comparing with the body swinging mechanism, potentially the ball will fly lower with a shorter distance, the shot will be less sharp and straight but tend to go to the right instead. This is due to the more difficulty in adjusting the clubface to square.
On the flip side, a high flexible club can cause the ball flies too high and prone to left deviate from the target line, since the contact angle is closed. The shot will be much more powerful than the golfer intended.
To sum up, a golfer needs to be clear about his/her natural swing tendency such as stance, direction and power to pick up the best fit club shaft that makes the best shots.

Source: ThoughtCo.com