Abstract: An apparatus is configured with one or more sensors arranged to detect a first shape-related parameter, one or more control elements arranged to provide a force, and circuitry operably connected to the one or more sensors and the one or more control elements to determine the force provided to the one or more control elements.

Abstract: A disclosure for a limited motion exerciser has been provided. The device as presently conceived is entirely driven by the user in a sitting position only. It would be placed on the floor, slightly forward of the knees such that movement of either leg away from the chair will be met with a predetermined resistance. Its physical size dictates a stroke of approximately 10 inches. Two traction elements are provided, one positioned beneath each foot. The elements are mechanically independent, allowing use of one or the other. Ideally both feet and lower legs would be active, employing equal and opposite motion, similar to normal walking. As designed, there is sufficient interior volume to install a user-adjustable load resistance that will be battery powered and recharged by the energy expended by the user. This feature (user-adjustability) will be covered by a subsequent patent application and is not detailed herein.

Abstract: A safety cable system for a fitness device including a resistance load and a user interface device. A redundant cable apparatus connects the resistance load to the user interface device for lifting the resistance load by a force applied to the user interface device. The redundant cable apparatus comprises two cables extending in redundant cable paths between the resistance load and the user interface device. The two cables can share the resistance load or one of the cables can be dormant until failure of the other cable.

Abstract: An adjustable reformer for exercising is provided. The reformer includes a frame, a carriage slidably mounted to the horizontal frame, and at least one resistance element connected to the carriage. A cord connects the carriage to at least one lower guide and at least one upper guide. Pulling the cord causes movement of the carriage along the frame against resistance provided by the resistance element. The guides can be height adjustable. The reformer can include a cord retraction system. Related methods of exercise are also provided.

Abstract: A stand-alone exercise apparatus includes a seat to support a user in a position thereon, and upper and lower body exercising assemblies which are configured for activation either sequentially or simultaneously to permit the concurrent exercising movement of his or her upper body area and lower body leg muscles, respectively, without necessitating that the user stop exercising when switching from upper body exercises to lower body exercises. The lower body exercising assembly includes a lower frame assembly which is operable to provide resistance exercise to the user's leg muscles, and which includes a selectively reciprocally movable pedal, platform or bar which is coupled to a suitable resistance mechanism, and which is engageable by the user's feet and/or legs as they are moved together in unified movement to effect leg extensions or curls.

Abstract: Systems, assemblies, and devices for mounting an exercise apparatus to a door. More particularly, an exercise system is mounted to opposing corners of a door and directed diagonally across a door. A bracket engages the door corner and is oriented to directed tension members of the exercise system at a diagonal across a front surface of the door. The bracket includes a door mount for coupling the bracket to four surfaces of the door. The bracket includes an exercise device mount adapted to couple to tension members, pulleys, or other exercise devices. The exercise device mount defines a mounting axis that is non-parallel and non-perpendicular relative to a top edge surface of the door.

Abstract: A shoulder rehabilitation and exercise device is disclosed which enables a user to perform internal and external rotations of both right and left shoulder. The device is comprised of a base plate, hydraulic damper, restrictor arm, actuator arm, elbow cup and hand grip. A smooth, fluid-like movement is achieved during performance of arcuate internal and external shoulder rotations while also providing automatic increases and decreases in resistance to such motion in response to user effort. In certain preferred embodiments, in addition to such automatic adjustment of resistance, the device includes a means of manually adjusting resistance. The device may be utilized to perform the aforementioned internal and external rotations on a user's right or left side without need for making any adjustments to the machine. Range of motion limitations may be set to control the arcuate degree of internal and external rotations performed.

Abstract: An exercise device for simulation of the action familiar to “tire flipping” is provided, having a base frame with a rail, a carriage including a pair of supports and a guide arm coupled to the base frame and the carriage. The guide arm allows guided rotational displacement of the carriage relative to the base frame with the carriage also being supported by at least one support received by the rail of the base frame at all time. One or more weight horns may be used to add additional mass to the carriage. A brake may be used to control the downward movement of the carriage after the carriage is actuated over vertical by a user or a lift that is “missed” causing the carriage to be safely lowered to a starting position.

Abstract: An exercise system is provided in which multiple exercise routines may be conducted with a single system. The exercise system may be used for skiing exercises, rowing exercises, and for weight training/resistance exercises. The exercise system may also be stored in a compact position and may by integrated with articles of furniture for space saving benefits. In one embodiment, resistance to motion is provided by one or more tension transmission members and may be selectively adjusted by controlling the configuration of the tension transmission member relative to a torsion spring. Use of intermediate devices between the spring and the tension transmission member are described that provide a non-linear relationship between force and displacement. In another embodiment, the tension transmission member may be configured in different positions by adjusting the position of movable pulleys, thereby allowing the device to be used for a number of different exercise routines.

Abstract: The exercise and training apparatus comprises: A base disposed on a supporting surface for the apparatus. an upper body support arrangement secured to the base frame in a manner that allows several positions from generally horizontal position to a generally vertical position. a lower body support arrangement secured to the base frame adjacent to the upper body support having a generally horizontal position. a head support secured to the upper body support arrangement. a pair of hand levers attached to the upper body support one on each side in a manner that allows the user's hands to move the levers in plural directions. a lever secured to the lower body support arrangement capable of receiving the user's legs in a manner that allows the user to move the lever in plural directions. an adjustable resistance means secured to each lever in order to provide resistance to movement of the lever.

Abstract: A boxer-fly exercise apparatus, hereinafter Boxer-fly, is provided. The Boxer-fly provides an additional exercise for performing strength training of a user's pectoral muscles. Specifically, the Boxer-fly presents a novel angle for conditioning a user's pectoral muscles derived from the motion performed by a boxer dropping his elbows to block his ribs. Furthermore, the apparatus can be used by any user looking to fully develop their chest muscles.

Abstract: A multi-station exercise gym comprises a frame, a sectored cable system that reduces the cable portion used during exercise, two high pulleys that are adjustable in width, two arm assemblies that can be selectively adjusted to alter the path of travel, two swiveling outer mid pulleys, two swiveling low pulleys, a centered mid pulley for exercises such as abdominal crunches, a leg extension-curl station, a pivoting seat assembly that provides proper pad support for all exercise movements, an adjustable hold down roller assembly for pull downs, a pair of adjustable arm pad assemblies for seated bicep curls and a low cost equally balanced, low friction incremental weight system.

Abstract: In order to measure a physical exercise condition data at a time of pre-testing and a muscle force training to accumulate and indicate them together with various set data, a muscle force training machine having a training apparatus main body and a training load applying apparatus is provided with a rotation detecting sensor which detects a rotating direction and an amount of rotation of a main shaft within the training load applying apparatus, and a data processing apparatus which stores the rotating direction and the amount of rotation from the rotation detecting sensor together with set data at least including a load amount, various body condition information of a training person and other data necessary for measuring in a data base, and processes them to make indicative data in forms of display data, print data and the like.

Abstract: The current invention is an exercise apparatus and method adapted for use with a leg exercising machine, the exercise apparatus including a base, a support beam having a proximal end and a distal end, wherein the proximal end portion extends from the base. Further included in the exercise apparatus is an omni-directional movable joint element that is disposed adjacent to the distal end portion and a grasping arm, with the grasping arm being received within the omni-directional movable joint element, wherein the grasping arm is operational to have omni-directional movement relative to the support beam. Also included in the exercise apparatus is a dampening element that is disposed between the support beam and the grasping arm, the dampening element is operational to dampen the omnidirectional movement such that an individual using the leg exercising machine can grasp the arm for stability and support for a soft skeletal joint support.

Abstract: The present invention is a group workout program that allows instructors to lead and teach multiple exercisers machine, free weight and other forms of exercise simultaneously. Participants within a single exercise area can do the same free weight, machine and accompanying exercises simultaneously. They can also circuit train in small, medium and large circuits doing the same or different exercises concurrently or simultaneously under the direction of an instructor. More than one exerciser can exercise on each machine at the same time and machines can be combined to deliver more exercises. An exerciser can do multiple exercises on a single machine either changing the configuration between exercises and also by leaving the configuration the same and simply moving between varying exercises. The workout program allows an instructor to teach exercises and exercise combinations in way where they can have a slow, medium, fast and mixed pace.

Abstract: Exercise apparatus and methods are disclosed herein. In one embodiment, an exercise assembly includes a load, a support assembly, a force-transferring assembly operatively coupled to the load and to the support assembly, and an exercise station operatively coupled to the force-transferring assembly. The exercise station includes a user interface, at least one adjustment assembly configured to adjust a position of the user interface, and an actuator assembly selectively engageable with the at least one adjustment assembly. The actuator assembly is configured to approximately simultaneously enable vertical and horizontal adjustment of the user interface when the actuator assembly is actuated to release the at least one adjustment assembly, and to approximately simultaneously disable adjustment of the user interface when the actuator assembly is actuated to lock the at least one adjustment assembly.

Abstract: Devices, systems and methods for receiving, recording, and/or displaying information related to physical exercise are disclosed herein. In one embodiment, an instrumented weight pin for use with a stacked weight exercise machine includes a shaft portion extending outwardly from a handle portion. In this embodiment, the shaft portion is configured to be removably positioned adjacent to one or more weights of the exercise machine to selectively engage the one or more weights during use of the exercise machine. The weight pin can further include a load sensor and/or an accelerometer. The load sensor and/or the accelerometer can provide information associated with an exercise set to a data storage device carried by the weight pin. The data storage device can be operably coupled to a user computer or other display device so that information relating to the exercise set can be displayed for viewing by the user.

Abstract: An exercise machine which has a seat and a backrest which are mounted for independent pivotal movement about an axis to respective chosen inclinations, structure which is fixed to, and which is movable together with, the seat, and resistance bands which are located on the structure.

Abstract: An exercise detection apparatus including: a load stage comprising a load surface onto which a load of parts or all of a human subject is applied; a load measurer for repeatedly or continuously measuring the load on the load surface; a calculator for calculating a difference between adjacent local maximum and minimum in the load varying over time measured by the load measurer repeatedly or continuously; and a detector for detecting a motion of the human subject when the difference calculated by the calculator is within a range.

Abstract: A health and fitness device is described, which may be operated hands-free without requiring the user to remain in a single position. The health and fitness device includes a casing with multiple openings, multiple cables where an end of a cable is configured to detachably couple with an end of another cable, and a tension mechanism unit housed within the casing is configured to retract the multiple cables into the tension mechanism unit through the multiple openings. When the one cable is coupled to the other cable, the health and fitness device may be secured onto an object or the positioned on the body of the user and used for various practical applications such as self-massage.

Abstract: Aspects of the present invention involve an exercise device configurable to allow a user to perform various exercises. The exercise devices include an adjustable bench assembly connected with a frame supporting adjustable arm and cable-pulley assemblies providing a user interface with a resistance system. In some embodiments of the invention, the adjustable bench assembly includes a bench seat and a pivotal back support supported on an adjustable bench frame. The exercise devices also utilize various configurations of adjustable arm assemblies that are selectively positionable for numerous exercises and to suit a user's particular body size and shape. Other embodiments of the exercise devices include a resistance system with a transmission supporting a plurality of resistance packs. The transmission allows a user to conveniently engage any number of resistance packs to change the resistance level for a particular exercise.

Abstract: A resistance system for fitness equipment includes a frame, a resistance source such as an elastic cord, coil or any other type of spring, weight, pneumatic or hydraulic cylinders. The resistance source is mounted to a resistance block with a load support. A support disk is provided that is movably mounted to the frame and adapted to enable selective engagement with the load support. A transmission member, including a pliable member such as a cable, belt or other member, is coupled to the resistance source. Movement of the support disk enables selective engagement of the resistance source. In this way one or more individual resistance sources can be selectively engaged or disengaged to vary the resistance to the user by actuation of a dial or other actuator as directed by the user.

Abstract: A gymnic and rehabilitative machine, comprising means (2) for allowing the user to apply forces and a load (3) mobile along a guide-way under the action exerted by the user by means of said means (2) for applying a force; the path followed by the load is curvilinear, offering various non-rectilinear trajectories during motion, with a variable geometry in the plane and in the space.

Abstract: A hand exercise device 100 and method for exercising human hands 102 and digits 104 comprising a plurality of separate digit sleeves 110 wherein the diameter and length are such that the separate digit sleeves 110 slide over the finger and thumb digits 105, 106 of the human hand 102; a magnetic element 120 is attached with the separate digit sleeve 110 near a distal end 116 of the separate digit sleeve 110, wherein the magnetic element 120 will facilitate a desired exercise in multidirectional movements when the magnetic element 120 is approximated near another magnetic 129 or ferrous metal surface 150.

Abstract: The invention relates to an apparatus for treatment, in particular physiotherapeutic treatment, of a part of the human body, in particular an arm, comprising a holder for fixing the body part to be treated, comprising a traction element, which acts on the body part with a predeterminable tension. The tension is applied by one or more weights acting on the traction element via a tension transmitter, it being possible for the tensile force acting on the body part to be varied or stopped at the beginning, during and/or at the end of the treatment by a counteracting force applied by a motor.

Abstract: An adjustable orthosis for, among other functions, flexing or extending a users joint, positioning a limb or digit during or after a surgical procedure, correcting foot drop due to soft tissue contraction, and augmenting soft tissue during weight bearing therapies. In a preferred form, the orthosis includes a padded shell adapted to be worn on a user's limb and a distal support to be worn on one or more digits of the hand or foot or on the forefoot or body of the hand. The padded shell is connected to the distal support solely via an elastic member such as surgical tubing, which also applies a tension force between the two supports. One end of the elastic member carries teeth that mate with a ratcheting device that permits the wearer (1) to gradually increase the tension between the supports and (2) to quickly release the tension.

Abstract: Apparatus suitable for pilates and other exercise comprises rails, supported on a box-like frame and an exercise carriage, mounted on the rails, wherein the carriage comprises a first carriage section and a second carriage section which sections can be (i) connected together to form a single exercise carriage which slides forwards and backwards on the rails, or (ii) disconnected to form two exercise carriages which independently slide forwards and backwards on the rails. The apparatus also has a seat with a spring-biased foot pedal and a spring-biased trapeze bar.

Abstract: An apparatus and system are disclosed for a fitness stick. The apparatus includes an elongated rod having a center point, a first end, and a second end. The apparatus also includes a first track connected with the rod and extending helically away from the center point along an outer surface of the elongated rod toward the first end, and a second track connected with the rod and extending helically away from the center point along an outer surface of the elongated rod toward the second end. Any point along the second track is reflectively symmetrical to a corresponding point on the first track about a central plane extending through the center point and orthogonal to a longitudinal axis of the elongated rod. The system includes the apparatus, first and second hand-slides, and a resistance band coupling the first hand-slide with the second hand-slide.

Abstract: A resistance exercise apparatus comprises a frame, a guide mounted on the frame, a resistance support movable relative to the guide along a path; and a resistance assembly for applying a resistance during an exercise. The resistance assembly includes a first resister having a first resistance, and a second resister having a second resistance. The first resistance and the second resistance are selectively and independently applied by the first resister and the second resister during an exercise. The first resister and the second resister are each arranged substantially symmetrically relative to the path.

Abstract: A device and method for bilateral upper extremity training for patients with a paretic upper extremity, the device facilitating cortical remodeling, sustained relearning, and improvement in functional outcomes in paretic and possibly non-paretic upper extremities. In one variation, the device includes a base, an adjustable chest plate for placing the user at a set distance from the device and isolating arm movement, an incline plate attached and inclinable relative to the base, two width plates adjustably attached to the incline plate, and two swivel plates adjustably attached to the width plates. In one variation, the swivel plates are swivalable relative to a fixed point in a plane parallel to the plane of the width plates. In another variation, the swivel plates are pivotably attached to the width plates. Other features of the device include a counter for counting user activity, and audible and visual cueing devices for facilitating sustained learning.

Abstract: A resistance chair with wheels assists users with performing correct abdominal crunches by guiding the user's effort. The resistance chair includes a seat connected to a hinged back with back support that extends to support the user's back and assist in the crunch recovery following the crunch extension.

Abstract: A recumbent exerciser includes a base, a right link and a left link are pivotably connected to the base and a right cam and a left cam are connected to the right link and the left link respectively. A right pedal and a left pedal are connected to two respective top ends of the right link and the left link, and a right swinging arm and a left swinging arm are connected to the right link and the left link. A resistance unit provides resistance to the right and left pedals and the right left swinging arms when the right and left cams are driven by operation of the user so as to exercise the user's hands and legs. The resistance unit is located remote from the seat so that the seat does not need to remove to maintain the resistance unit and the cams.

Abstract: Exercise assemblies having self-adjusting pad devices are disclosed. In one embodiment, an exercise assembly includes a load and a force-transferring assembly operatively coupled between the load and at least one exercise station such that a training force applied to the at least one exercise station induces an associated force on the load. The at least one exercise station includes at least one pad member slideably coupled to a support member and configured to adjust to a lateral position along the support member corresponding to a portion of the user's body. The at least one pad member may have an attachment opening that includes a first portion sized to receive a shaft portion of the support member, and a second portion sized to receive a retaining portion of the support member, the retaining portion being larger than the shaft portion of the support member.

Abstract: The invention relates to a training apparatus, in particular for the muscle system of the hand, arm and upper body, wherein the apparatus has an elongate casing with at least an essentially circular internal cross section, in the interior of which at least one ball (5) is situated in a freely movable manner between shock absorbers (6). There are various forms of such training apparatuses. Their disadvantages include relatively monotonous training and the difficulty or impossibility of using them to train during another activity, for example during running. In order to avoid this, the invention is characterized in that the casing is of flexible design over at least part of its longitudinal extent, in that the ends of the casing are fastened to a handle part, and in that handle part and casing lie at least essentially on one plane.

Abstract: A device and method are disclosed for training the abdominal muscles of a user in an upright position. The device and method are configured to lead the upper torso of the user while bending along a preferred path, so that the backbone is bent in a proper manner causing a proper training of the abdominal muscles.

Abstract: A sit-up exerciser has a base, a seat and a footrest assembly mounted on the base, and a linkage assembly mounted between base and the seat. The linkage assembly has a handle arm, a back arm and a linking rod connected to each other. At least one rear resilient element is connected between the seat and the back arm and at least one front resilient element is connected between the footrest assembly and the handle arm. The resilient elements assist in performing sit-ups and the back arm supports a neck and vertebral column to prevent injury and damage.

Abstract: An exercise device for strengthening the core or midsection of the body that is suitable for use in a professional work environment. The exercise device comprises a domed seat positioned atop a plurality of baffled sections. The domed seat is deformable, allowing it to support and conform to the buttocks of a user when sitting on the device. The baffled sections are also deformable, allowing the seat to shift in all directions along a horizontal plane as a user's weight naturally shifts while sitting on the device. As the baffled sections deform and the seat persistently shifts over the course of a given period of time, a user's core muscles repeatedly tense in order to stabilize the body. The constant tension of the muscles over that period of time simulates a workout, particularly in the midsection of the body.

Abstract: An apparatus for simulating sculling or rowing on water includes a support frame with foot rests, a sliding seat, bilateral oars that are rotationally coupled to a set of actuators, integrated input velocity and torque sensors, computer and computer display. Each actuator incorporates a mechanical transmission, a rotational inertial mass, a variable linear and a variable non-linear damping element. The damping elements can be controlled manually or automatically by computer programs under user control.

Abstract: Aspects of the present invention involve an exercise device configurable to allow a user to perform various exercises. The exercise devices include an adjustable bench assembly connected with a frame supporting adjustable arm and cable-pulley assemblies providing a user interface with a resistance system. In some embodiments of the invention, the adjustable bench assembly includes a bench seat and a pivotal back support supported on an adjustable bench frame. The exercise devices also utilize various configurations of adjustable arm assemblies that are selectively positionable for numerous exercises and to suit a user's particular body size and shape. Other embodiments of the exercise devices include a resistance system with a transmission supporting a plurality of resistance packs. The transmission allows a user to conveniently engage any number of resistance packs to change the resistance level for a particular exercise.

Abstract: A combined anaerobic and aerobic exercise system comprises a multi-part frame, for example a telescoping frame, or a pivoting frame. The aerobic system may include an elliptical exercise device, while the anaerobic system may include a cable-based system wherein resistance is adjustable. An electronic console system at the exercise system allows a user to view progress in both anaerobic and aerobic workouts, and to send input signals that adjust anaerobic and aerobic resistance mechanisms.

Abstract: An exercise machine in one embodiment includes a frame, a pivot arm, an adapter mounted on the pivot arm to adjust between various adapter positions, and an operator engagement device mounted on the adapter to adjust between various engagement device positions. The adapter is typically telescopically mounted on the pivot arm to extend and retract along a first axis about which the adapter is also rotatable. The engagement device is typically telescopically mounted on the adapter to extend and retract along a second axis which is transverse to the first axis and about which the engagement device is rotatable. The embodiments may include a pivotal connection between the pivot arm and a generally T-shaped handle for positioning the handle and for enhancing the use of the handle. Handle extenders may be included to lengthen a typical T-shaped handle. Unique cable and pulley configurations are also disclosed.

Abstract: One embodiment relates to a fitness development system. The fitness development system generally comprises an exercise chamber and an object. The exercise chamber may comprise a base, an inclined floor, and one or more barriers. The base may define a substantially horizontal axis to support the exercise chamber, while the inclined floor may comprise an angle of inclination that defines a degree of separation of the inclined floor from the base, wherein the angle of inclination maximizes fitness development of an individual advancing the object up the inclined floor against a gravitational pull on the object. The barriers may substantially enclose the exercise chamber. The object may comprise a configuration enabling maximum fitness development of the individual advancing the object up the inclined floor.

Abstract: An exercise machine which has a base with at least three spaced apart legs and two spaced apart handles attached to the base. A rocker assembly that includes a rocker fastener and first and second sets of spaced apart brackets is provided where the second set of brackets rotates relative to the first set of brackets along a longitudinal axis of rotation. The longitudinal axis of rotation passes between the handles and is substantially parallel to the handles and the second set of brackets rotates only about the longitudinal axis of rotation. The first set of brackets is secured to the base and the second set of brackets is secured to the underside of a rotation assembly. The rotation assembly is coupled to a seat to enable rotation of the seat relative to the second set of brackets. The rotation assembly includes a stop to limit rotation of the seat.

Abstract: A resistance chair with wheels assists users with performing correct abdominal crunches by guiding the user's effort. The resistance chair includes a seat connected to a hinged back with back support that extends to support the user's back and assist in the crunch recovery following the crunch extension.

Abstract: An exercise device having many advantageous features is described, including the ability to provide a combination of grips to the user, and the ability to easily mount the device to a wall. One exercise device described is an inelastic resistance device having a combination grip that includes hand grips and a loop. The hand grip and loop may be used as a foot grip, or alternatively, just the hand grip can be used by the hand. The selection of a specific accessory grip allows the user to exercise by specific body parts and provides for a greater number of possible exercises.

Abstract: A kinematic rotating-tilting mechanism (10) that consists of six major elements: a housing (12), a housing flange assembly (42), a platform flange assembly (70), a platform base (90), a resilient section (110) and an angled shaft (120). The housing (12) includes an upper end (18) having a cover (20) to which is attached the housing flange assembly (42), and attached to the lower surface (98) of the platform (90) is the platform flange assembly (70). The shaft (120) has a lower vertical section (122) that is rotatably attached to the housing flange assembly (42), and an upper angled section (126) that is rotatably attached to the platform flange assembly (70). The platform base (90) has an upper surface (96) to which is attached a resilient section (110). A person who is located on the resilient section (110) can produce torque by shifting their body weight.

Abstract: The invention relates to a multifunctional trainer for strength training. The trainer comprises a body (1), a counterforce unit (2) for generating a counterforce to resist the exercise movements, a set of movement arms (31, 32) supported to the body (1) for performing different exercise movements, and a set of elongated tensile elements (41, 42) arranged to act between the counterforce unit (2) and the movement arms (31, 32) for applying the counterforce resisting each exercise movement from the counterforce unit to the movement arms.

Abstract: A portable exercise device. The portable exercise device includes a recoil assembly, a clutch assembly, an adjustable resistance assembly, a housing assembly, and a flexible cable member. The clutch assembly is coupled to the recoil assembly. The adjustable resistance assembly is coupled to the clutch assembly. The housing assembly includes a first portion and a second portion. The first portion defines and opening therethrough and surrounds the recoil assembly and the clutch assembly. The second portion is rotatably coupled to the first portion, defines a configured projection, and surrounds the adjustable resistance assembly. The flexible cable member is coupled to the recoil assembly, and extends through the opening defined by the first portion of the housing assembly.

Abstract: A loading device for an exercise machine includes a lever arm and a nitrogen gas compression spring in a force triangle that provides easy adjustment of the resistive load presented to a user. The nitrogen gas compression spring and the selected portion of the lever arm comprise two legs of the force triangle, with a slidable coupling selectively interconnecting the nitrogen gas compression spring with the lever arm at adjustment points on the lever arm. Both the nitrogen gas compression spring and the lever arm are pivotally mounted on a rigid member, with the distances between their pivots forming the third leg of the force triangle. The nitrogen gas compression spring exhibits a high resistance, a flat spring rate and is of rigid construction so that the lever arm and nitrogen gas compression spring are self-supported at all times.

Abstract: A resistance chair with wheels assists users with performing correct abdominal crunches by guiding the user's effort. The resistance chair includes a seat connected to a hinged back with back support that extends to support the user's back and assist in the crunch recovery following the crunch extension.