C2の解説は下記の通り。Crokerほど具体的なものではなく、選手の好みに応じてお選び下さいという感じ。一点注目すべきは、硬すぎるシャフトは疲労障害（疲労骨折？）の原因となり得ると言う点。
Shaft stiffness is mostly a matter of personal preference. Softer shafts will flex more easily on the drive. Some people like this softer feel; others feel it is a waste of energy. Stiffer shafts will flex less on the drive. Some people like this stiff feeling; others feel it can contribute to overuse injuries. Most people order medium stiffness unless they have a clear personal preference either way.
