s chest with respect to his waist an important advantage of the placement of links 30 and 32 below seat 22 is that a user of the machine may approach the machine and sit astride it on seat 22 without obstruction from side pieces extending at or above his waist as exists with many prior art abdominal exercise machines resistance to the rotation of rotating member 24 with respect to stationary member 20 is provided in the embodiment of fig1 and 2 by means of viscous fluid resistance cylinder 44 connected between lower link 32 and stationary support member 20 such cylinder 44 may be pivotally connected to stationary support member 20 by means of pin 50 through bracket 52 secured to member 20 and to link 32 by means of pin 54 through bracket 56 secured to link 32 alternatively resistance to the rotation of rotating member 24 with respect to stationary member 20 may be provided as illustrated by fig3 by means of stacked weights 64 and pin 62 of extension 60 to lower link 32 other resistance means known in the exercise machine art of course may also be used fig4 a and 4b illustrate how the lengths and placement of links 30 and 32 and the placement of pivots 38 34 36 and 40 may be established to assure that the center of rotation of chest pad 26 is about a point p disposed at the waist of a user sitting astride the machine fig4 a illustrates.