referring to fig1 and fig3 , resistance chair 10 includes seat 12 pivotally secured to first end 14 of first arm 15 which is pivotally secured to second end 17 of second arm 18 . first end 20 of the second arm engages axle 21 and any suitable wheels such as wheels 22 and 23 may be secured to axle 21 to enable extension of resistance chair 10 to extended position 30 as illustrated in fig2 . any suitable back support elements such as rollers 24 and or shoulder support 25 may be secured to first arm 15 . rollers 24 may be secured at any suitable position on first arm 15 and may be included in a backrest such as backrest 27 that may swivel at the point of attachment to first arm 15 . seat 12 may be molded plastic , metal , foam or a combination of wood , steel and upholstery . front edge 12 f may be higher relative to rear edge 12 r to place a user at a slight incline into the back support . this position ensures optimal comfort when performing an abdominal crunch . one or more resistance bands such as bands 26 may be used to provide selectable resistance to a user moving from start 20 position 28 of fig1 to extended position 30 of fig2 . the resistance bands also assist the user to perform a correct crunch motion when moving from extended position 30 to start position 28 . resistance bands 26 may be secured between axle 21 and axle 32 using any suitable technique such as band engagement elements 33 directly secured to axle 21 and seat 12 secured to axle 32 . optional shoulder straps 34 may be attached to hinge 35 between first arm 15 and second arm 18 or to an extension such as extension 15 b from first arm 15 . straps 34 may provide additional resistance to a user seeking to extend the crunch position and continue to move their upper body forward past start position 28 . this extends the crunch , contracts the user &# 39 ; s abdominal muscles farther than the start position and engages the user &# 39 ; s arms in the exercise . in use a user sits upon seat 12 with the user &# 39 ; s back adjacent to back rollers 24 in start position 28 of fig1 . the user must lean back against the back rollers 24 and shoulder support 25 using the user &# 39 ; s back muscles to push against the back rollers 24 and shoulder support 25 . wheels 22 and 23 will begin to roll away from the user and permit first arm 15 and 10 second arm 18 to fold to a horizontal position parallel to the ground as in extended position 30 of fig2 . the transition from start position 28 of fig1 to extended position 30 of fig2 stretches resistance bands 26 . the energy stored in stretched resistance bands 26 counteracts a portion of the gravitational force on the user &# 39 ; s upper body and assists the user to perform an abdominal crunch to return the user &# 39 ; s upper body from the extended position 30 of fig2 to at least start position 28 of fig1 . by performing these movements the user is doing an abdominal crunch with back support and resistance that stretches the lower back muscles , forces the user to use more muscles when pushing backwards , and supporting the user when the user moves from the fully extended position to the upright start position , thereby creating a more comfortable , efficacious exercise . while the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed , they are merely illustrative of the principles of the inventions . other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims .
a resistance chair with wheels assists users with performing correct abdominal crunches by guiding the user &# 39 ; s effort . the resistance chair includes a seat connected to a hinged back with back support that extends to support the user &# 39 ; s back and assist in the crunch recovery following the crunch extension .