A measure of how much and how easily a shaft bends when swung. Shafts are generally offered in a range of flexes including regular, stiff and extra-stiff, with special designations for seniors and women.

Golf club shaft flex is a key determinant of club performance based on a golfer’s swing speed and tempo. Players with high swing speeds, such as professionals and skilled amateurs, may perform best with stiffer shafts. Those who swing more slowly are advised to use highly flexible shafts, which can add distance and height to shots.

Most shafts for irons, hybrids and woods list the flex as a symbol near the grip end of the club.