Patent Publication Number: US-7717832-B2

Title: Shoulder press exercise machine

Description:
RELATED APPLICATION 
   The present application is a Continuation of co-pending U.S. patent application Ser. No. 10/699,992 filed on Nov. 3, 2003, the entire disclosure of which is incorporated herein by reference. 

   BACKGROUND 
   1. Field of the Invention 
   This invention relates generally to exercise machines, and is particularly concerned with an exercise machine for performing shoulder press exercises which has a moving user support. 
   2. Related Art 
   Free weight shoulder press exercises using barbells or dumbbells involve an exerciser in a standing position holding dumbbells at a position just above their shoulders, and then raising the weights over their head. The free standing shoulder press movement is one of the most fundamental exercises and is one of the standard measures of strength. However, it can be difficult for many people to perform. It requires balance and coordination as well as strength for someone to raise a weight or weights over their head with a slight arcing motion while maintaining balance. This is a compound or multi-joint movement which involves the front and outer deltoid muscles of the shoulder. Improper form during the exercise (jerking or swinging the weights upward, leaning forward or arcing backward) can throw the exerciser off balance, which makes the exercise more difficult, increases stress to the joints, and can lead to possible injury. 
   In order to help the less conditioned exerciser perform this basic exercise, the seated shoulder press bench was developed. This provided stabilizing support by placing the user in a seated position with back support, preventing the user from swinging the weights, walking with the weights, or arching their back while performing the exercise. A further safety development replaced the free weight movement with a machine utilizing an exercise arm pivotally attached to the stationary bench or user seat. Such machines typically have an exercise arm movably mounted on a stationary frame with a seat and back pad or user support rigidly mounted on a stationary frame, with plate loading, selectorized weight stack, hydraulic, pneumatic or elastic bands for resistance. 
   Some known shoulder press exercise machines are described in U.S. Pat. No. 5,554,089 of Jones, U.S. Pat. No. 5,810,701 of Ellis, and U.S. Pat. No. 5,562,577 of Jones. Each of these machines has a main frame, a user support rigidly mounted to the main frame, and a plate-loaded exercise arm pivotally mounted on the main frame. All three of these machines have exercise arms that provide a converging exercise motion, because the user engaging handles are forced inwards as the exercise arm is urged upward in performing a shoulder press exercise. Each of the machines has weight receiving pegs on the outboard side of the exercise arm, increasing the overall size of the machine and creating a safety hazard as the weight swings during exercise machine use. Jones and Ellis provide an exaggerated arc in the exercise motion, preventing the user engaging handles from ending up in line with the side centerline of the user&#39;s body at the end of the exercise, as is the case with the free weight shoulder press. 
   U.S. Pat. No. 4,844,456 of Habing describes a machine providing multiple exercises, including a forward inclined shoulder press. Again, the user support is fixed in position, and an exaggerated arc is provided by the pivoting exercise arm. Back supported shoulder press exercise capability is also provided in the machines described in U.S. Pat. Nos. 5,447,480 and 5,549,530 of Fulks, but again the pivoted exercise arm provides an exaggerated arc and prevents the user engaging handles from ending up in the optimum finish position for a shoulder press exercise. U.S. Pat. No. 6,080,091 of Habing describes an exercise machine with a pressing arm assembly comprising a main arm pivotally mounted on the main frame and two handle arms pivotally coupled to the main arm cross beam. The handle arms can pivot freely inwardly and outwardly. The exercise resistance, in this case a weight stack, is associated with the main arm. This design provides a straight pressing motion as well as an inward converging press motion and an outward to inward “fly” motion. Again, the user seat or support is fixed in position on the frame. 
   Some known multi-purpose exercise machines for performing various different types of exercise have movable seats or user supports. In U.S. Pat. No. 5,330,405 of Habing, the machine has a stationary base frame, a lever arm pivotally mounted on the frame, and a sub frame pivotally connected to the base frame and supported by the lever arm. The sub frame comprises a user support and an exercise arm linked to the lever arm by cables and pulleys. The exercise arm for performing pressing exercises is pivotally connected to a portion of the sub frame at a location above the user. In order to perform a shoulder press, the user must sit on the user support leaning forward at an angle without benefit of back support, pressing the exercise arm forward and rotating it about its pivotal connection to the sub frame in order to pull the cables and cause the sub frame to lift. 
   U.S. Pat. No. 5,669,865 of Gordon describes a multi-purpose user support with a hinged, two-piece user support that folds and unfolds with each exercise repetition. The user support comprises a seat portion and a back portion which are pivotally connected together, and is pivotally connected to the main frame. A first exercise arm pivoted to the frame provides pressing and pull down exercises. The seat and back rest do not travel in a fixed relationship to each other, but fold and unfold during the exercise, working the abdominal and low back muscles even when other exercises are being performed. Due to the separate motion of the seat and back rest, additional supports such as a foot rest, safety belts, and thigh gripping surfaces are required to keep the user properly and safely positioned. In this machine, most of the combined weight of the user and user support remains on one side of the gravitational centerline of the user support, and this weight is used as a partial exercise resistance. Due to the working of the abdominal and low back muscles in every exercise movement, including press exercises, the exerciser cannot properly isolate any one specific muscle or muscle group. Because of this, the exerciser cannot fully fatigue other muscles, since the abdominals and lower back will always fatigue first. 
   None of the prior art exercise machines for performing shoulder press exercises properly simulate the slight arcing motion as well as the start and finish positions found in a free weight shoulder press exercise, while properly supporting the user&#39;s body throughout the exercise movement. Most or all shoulder press exercise machines with fixed user supports have an exaggerated and unnatural arcing movement during the exercise, and do not provide the proper starting and finishing alignment between the user and exercise arm handles. 
   SUMMARY 
   In one aspect, a shoulder press exercise machine is provided, which comprises a main frame having a user support mount, a user support frame movably mounted on the user support pivot mount for supporting a user in an exercise ready position and movable between a start position and an end position, an exercise arm movably mounted on one of the frames, the exercise arm having at least one user engagement device for gripping by a user in performing a shoulder press exercise and the exercise arm being movable between a start position in which the user engagement device is located in front of the shoulders of a user in a seated position on the user support frame and an end position higher than the start position in which the user engagement device is located above the head of the user, and a connecting linkage connecting movement of the exercise arm to movement of the user support frame, whereby movement of the exercise arm from the start to the end position simultaneously rotates the user support frame from the start to the end position, and a load for resisting movement of at least one of the moving parts of the machine, the combined motion of the user support frame and exercise arm between the start and end position substantially replicating the natural movement of the human body when performing a free weight shoulder press exercise. 
   In one embodiment, the user support mount is a pivot mount on the main frame which defines a vertical, gravitational center line of the pivotal movement. In some exemplary embodiments, the gravitational center line is positioned such that the combined weight of the user and user support frame is distributed on each side of the gravitational centerline of the pivot in both the start and end position and only a portion of the combined weight passes through the gravitational centerline during the exercise movement, so that a major portion of the weight of the user and user support does not remain on one side only of the gravitational centerline over the entire exercise movement. The user support frame has a first and second user support portions which support different locations on a user&#39;s body, and the user support portions are in fixed relation to one another and travel together in fixed relative positions between the start and end position of the user support frame. This keeps the user safely in the same, supported position throughout the exercise movement. The user support frame may be in a slightly reclined position at the start of the exercise, and moves from this position into a more reclined position at the end of the exercise movement. 
   The first user support portion may be a seat pad while the second user support portion may be an upper body support or a lower leg support. In other embodiments, both an upper body support and a lower leg support are provided on the user support frame. Alternatively, a stationary foot rest may be provided on the main frame. In one embodiment, the user support mount is positioned behind the hips of a user seated on the user support frame, and the exercise arm, which may be a single arm for dependent movement, or may be split into two separate arm portions for independent movement, is pivoted to the frame at a location behind the user, and extends forward on opposite sides of the user support frame to place the user engagement device or handle in a position for gripping by the user. 
   As the user pushes the exercise arm from the start position to the finish position, the exercise arm movement is linked to the user support frame by the connecting link. In one embodiment, where the user support mount is a pivot mount, movement of the exercise arm simultaneously and automatically rocks or rotates the user support frame from the start position to the end position. This rocking movement makes the exercise more fun to perform. The pivoting user support frame automatically aligns with the exercise arm to maintain proper positioning of the user throughout the exercise movement. 
   In one embodiment, the connecting link pivotally connects the user support frame to the exercise arm so that upward movement of the exercise arm about its pivotal connection to the main frame forces the user support frame to pivot rearward about its pivotal connection to the main frame. The connecting link has a first pivot connection to the user support frame and a second pivot connection to the exercise arm. The first pivot connection may be higher than the second pivot connection, so that the connecting link pulls the user support frame to force it to rotate. Alternatively, the first pivot connection may be lower, so that the connecting link pushes the user support frame to rotate into the end position. 
   In an alternative arrangement, the exercise arm may be slidably mounted for linear movement on the main frame, rather than pivotally connected to the main frame. In this alternative, as the exercise arm is pushed upward, the connecting link to the user support frame pulls the user support rearward. 
   The shoulder press exercise machine provides proper positioning of the user in both the start and end position, as well as a slight arcing motion of the upper body of the user which simulates the natural body movement found in a free weight exercise. Because movement of the exercise arm is linked to movement of the user support frame, the self-alignment of the user and user support throughout the exercise motion is automatic and continuous throughout the entire exercise range of motion. This combined movement maintains a beneficial alignment relationship between the user positioned on the user support frame and the user engaging device or handles on the exercise arm. The combined motion of the user support frame and exercise arm accurately replicates the natural, gradual rearward arcing arm movement of a traditional free weight barbell press exercise. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The details of the present invention, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
       FIG. 1  is a front perspective view of a shoulder press exercise machine according to a first embodiment, with the user support and exercise arm in the start position adopted at the beginning of an exercise movement; 
       FIG. 2  is a rear perspective view of the machine of  FIG. 1 , also in the start position; 
       FIG. 3  is a side elevation view of the machine of  FIGS. 1 and 2 , with the user support and exercise arm in the end position adopted at the end of an exercise movement; 
       FIG. 4  is a side elevation view similar to  FIG. 3 , but illustrating the exercise start position as in  FIGS. 1 and 2 ; 
       FIG. 5  is a side elevation view similar to  FIG. 4 , illustrating a user seated on the user support in the exercise start position; 
       FIG. 6  is a side elevation view similar to  FIG. 3 , with a user seated on the user support, illustrating the user&#39;s position at the end of the shoulder press exercise; 
       FIG. 7  is a side elevation view of a modified shoulder press exercise machine, illustrating the exercise start position; 
       FIG. 8  is a side elevation view of the machine of  FIG. 7 , illustrating the exercise end position; 
       FIG. 9  is a side elevation view illustrating a modification of the machine of  FIGS. 1 to 6  to provide adjustment of the starting height of the exercise arm; 
       FIG. 10  is a side elevation view of a shoulder press exercise machine according to another embodiment illustrating the exercise start position; 
       FIG. 11  is a side elevation view of the machine of  FIG. 10 , illustrating the exercise end position; 
       FIG. 12  is a rear perspective view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 13  is a rear perspective view of the machine of  FIG. 12 , illustrating the exercise end position; 
       FIG. 14  is a top plan view illustrating modified, pivotally mounted user engaging handles for use in any of the preceding embodiments; 
       FIG. 15  is a top plan view similar to  FIG. 14 , illustrating handles similar to those of  FIG. 14  in fixed attachment to an exercise arm; 
       FIG. 16  is a rear perspective view of a shoulder press exercise machine with a split, two-piece exercise arm according to another embodiment, illustrating the exercise end position for one exercise arm and the user support; 
       FIG. 16A  is a side elevation view of the machine of  FIG. 16 , also illustrating the exercise end position; 
       FIG. 17  is a side elevation view of a modified shoulder press exercise machine, illustrating the exercise start position; 
       FIG. 18  is a side elevation view of the machine of  FIG. 17 , illustrating the exercise end position; 
       FIG. 19  is a side elevation view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 20  is a side elevation view of the machine of  FIG. 19 , illustrating the exercise end position; 
       FIG. 21  is a close-up view of the interlocking gears of the machine of  FIGS. 19 and 20 ; 
       FIG. 22  is a side elevation view of another modified shoulder press exercise machine, illustrating the exercise start position; 
       FIG. 23  is a side elevation view of the machine of  FIG. 22 , illustrating the exercise end position; 
       FIG. 24  is a side elevation view of a modified shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 25  is a side elevation view of the machine of  FIG. 24 , illustrating the exercise end position; 
       FIG. 26  is an enlarged, more detailed view of the connecting linkage of the machine of  FIGS. 24 and 25 ; 
       FIG. 27  is a side elevation view of a shoulder press exercise machine according to another embodiment, illustrating the exercise end position; 
       FIG. 28  is a side elevation view of the machine of  FIG. 27 , illustrating the exercise start position; 
       FIG. 29  is a side elevation view of a modified shoulder press exercise machine, illustrating the exercise start position; 
       FIG. 30  is a side elevation view of the machine of  FIG. 29 , illustrating the exercise end position; 
       FIG. 31  is a side elevation view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 32  is a side elevation view of the machine of  FIG. 31 , illustrating the exercise end position; 
       FIG. 33  is a side elevation view of a shoulder press exercise machine according to another embodiment, illustrating the exercise end position; 
       FIG. 34  is a side elevation view of the machine of  FIG. 31 , illustrating the exercise start position; 
       FIG. 35  is a rear perspective view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 36  is a rear perspective view of the machine of  FIG. 35 , illustrating the exercise end position; 
       FIG. 37  is a side elevation view of the machine of  FIG. 35  in the start position with a user seated on the user support; 
       FIG. 38  is a side elevation view similar to  FIG. 37 , illustrating the exercise end position of the user, user support and exercise arm; 
       FIG. 39  is a side elevation view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 40  is a side elevation view of the machine of  FIG. 39 , illustrating the exercise end position; 
       FIG. 41  is a rear perspective view of a shoulder press exercise machine according to another embodiment, illustrating the exercise start position; 
       FIG. 42  is a rear perspective view of the machine of  FIG. 41 , illustrating the exercise end position; 
       FIG. 43  is a side elevation view of the machine of  FIG. 41  in the start position; and 
       FIG. 44  is a side elevation view similar to  FIG. 43 , illustrating the exercise end position. 
   

   DETAILED DESCRIPTION 
   Certain embodiments as disclosed herein provide for a shoulder press exercise machine in which movement of an exercise arm is linked to movement of a user support frame. 
   After reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example only, and not limitation. 
     FIGS. 1 to 6  illustrate a shoulder press exercise machine  10  according to a first embodiment, which duplicates a free weight overhead press exercise without the disadvantages of a free weight exercise, i.e. balance, coordination, and strength to follow the proper movement path, and possible injury if the proper movement is not followed. Instead, the shoulder press machine  10  constrains the user to follow the proper exercise path, while fully supporting the user&#39;s body throughout the exercise for comfort and safety. The exercise carried out by this machine mimics the natural, slightly rearward arcing movement of a user&#39;s arms from the start to the finish position of an equivalent free weight shoulder press exercise. 
   The exercise machine  10  basically comprises a main frame  12 , a user support frame  14  pivotally mounted on the main frame, an exercise arm  15  pivotally mounted on the main frame and linked to the user support frame by a connecting link  16 , and an exercise resistance such as selectorized weight stack in housing  18  linked to the user support frame  14 . The main frame  12  comprises a horizontal base section  20 , a rearwardly inclined, rear upright section or strut  22 , and a pivot mount section  24 . The base section  20  is connected to the vertical weight stack housing  18  at its forward end. The weight stack housing  18  encloses a weight stack (not visible in the drawings) which runs on two guide rods (also not visible), as is standard in the field. The pivot mount section  24  comprises a brace strut or tube that is secured to both the base section and the rear upright section of the frame. 
   The user support frame  14  is designed to support a user in an exercise ready position. In this embodiment, the user support frame is generally L-shaped with a base  25  on which a seat pad  26  is adjustably mounted, and an upright  27  on which a back pad  28  is mounted for supporting a user&#39;s upper body. A foot plate or footrest  30  is secured to the forward end of the base  25 . The frame  14  is pivotally mounted on the pivot mount section  24  of the frame via a pivot  32  located on the upright  27  close to the junction between the base and upright sections, so that the pivot is positioned directly under an exerciser  34  (see  FIGS. 5 and 6 ) at a location close to the exerciser&#39;s hips. The seat pad  26  is mounted on a strut or post  35  which is telescopically engaged in tube  36  to allow the height of the seat pad relative to the frame to be adjusted for users of different heights. A stop  38  on the main frame adjacent the forward end of the user support frame acts to support the user support frame in the starting position of FIGS.  1 , 4  and  5 . 
   The exercise arm  15  is best illustrated in  FIGS. 1 and 2 , and has a first elongate member or strut  40  having one end pivoted to the top of upright frame strut  22  via pivot  42 , and a U-shaped member having a central section  44  secured to the opposite end of strut  40  and opposite handle arms extending on opposite sides of the user seat, with user engaging handles  45  at the ends of the handle arms. The connecting link  16  comprises an arm having a first end pivoted to an intermediate point on the first member or strut of the exercise arm  15  via pivot  46  and a second end pivotally secured to the upper end of the rear upright  27  of the user support frame via pivot  48 , as best illustrated in  FIGS. 3 to 6 . 
   A cable and pulley linkage, only part of which is visible in the drawings, links the base  25  of the user support frame to the weight stack. The cable and pulley linkage comprises a cable  50  extending from an anchor  52  on the base  20  of the main frame, around a pulley  54  on the underside of user support base  25 , around a second pulley  55  on the main frame base  20 , and from there through the base  20  and into the weight stack housing, where it extends around further pulleys before linking to a selectorized weight stack in a conventional manner. 
     FIGS. 5 and 6  illustrate a user  34  performing a shoulder press exercise on the machine  10 , showing the angular orientation of the user support  14  in both the start and finish position, as well as the amount of cable pull, which determines the resistance felt by the user. To perform the exercise, the user sits on the seat in the start position of  FIG. 5 , where the seat is in a slightly rearwardly reclined position and the handle arms are in a lowered position with the hand grips below the user&#39;s chin and just in front of the user&#39;s shoulders. The user places their feet on the foot rest  30 , and grabs the handles  45 . In  FIGS. 5 and 6 , the dotted line  56  represents the gravitational centerline of the user support pivot  32 , which is the gravitational centerline of the user performing the exercise. The dotted line  58  represents the side centerline of the exerciser. As can be seen in  FIG. 5 , the start position places the user in a slightly reclined position, with the rear upright  27  at an angle of around 110 degrees to the base of the main frame, with their hands at approximately shoulder level and forward of the side centerline of their body. In this position, the gravitational centerline  56  aligns with the center of the exerciser&#39;s shoulders and rearward of their hip, and approximately 75% of the combined user and user support weight is positioned forward of the gravitational centerline  56 . 
   From the position of  FIG. 5 , the user pushes the handles upwards, rotating the exercise arm rearwardly about its pivot  42 . At the same time, the exercise arm pulls the connecting link  16 , which in turn causes the user support to rotate rearwards about pivot  32 . This movement of the user support is resisted by the weights linked to cable  50 . The user is placed in a back or upper body supported position with their hands slightly forward of the shoulders in the start position, as illustrated in  FIG. 5 , and then follows the slight natural arcing movement of a barbell press, finishing the exercise in a substantially reclined position of around 135 degrees to the horizontal or base of the frame, and around 45 degrees to the gravitational centerline, with their arms fully extended and in line with the side centerline  58  of their body, as illustrated in  FIG. 6 . The seat therefore reclines through an angle of around 25 degrees between the start and end positions. At the same time, the cable is pulled up by approximately 13 inches, based on subtracting the added total cable length in the start position (9.99 inches) from the added total cable length in the end position (22.77 inches). 
   The start and finish positions in this machine substantially mimic the start and finish position of a free weight shoulder press. The user is placed in a back supported, rearward lean at the start of the exercise, and finishes in a more rearward lean with their arms extending straight overhead. Because the user support rotates in the same direction as the exercise arm, the arcuate path of the exercise arm relative to the user support is reduced. This results in a more natural feeling exercise movement which more accurately replicates corresponding free weight exercise. The exercise movement provided with this machine accurately simulates the slight, natural arcing movement the arms go through when performing a barbell or dumbbell free weight shoulder press exercise. At the same time, the rocking movement of the user support while extending the arms makes the exercise more interesting and fun to perform. This may increase the user&#39;s motivation to repeat the exercise. 
   It can be seen that the position of the user support pivot beneath the user&#39;s body distributes the weight of the user&#39;s body and the support frame on both sides of the gravitational centerline in both the start and finish position of the exercise. The starting position in this case places the user support pivot rearward of the exerciser&#39;s hips, with the gravitational centerline  56  in line with the centerline of their shoulders. While the majority of the user&#39;s body starts forward of the gravitational centerline, the user rotates rearwards through this centerline during the exercise, and finish with the centerline bisecting the middle of their torso for a more evenly balanced distribution of weight at the end of the exercise. 
   In the starting position, approximately 75% of the total weight of the user and user support is on the forward side of the centerline  56 . As the exercise arm is moved rearward, more of this weight passes through the gravitational centerline with a more even distribution of weight (approximately 50% on each side of the pivot) is achieved at the end of the exercise. This reduction is gradual and continuous and is not noticed by the user. The combined weight of the user and user support still has a reduced effect on the amount of starting resistance, since part of the user&#39;s weight is still placed rearward of the user support pivot, acting as a counterbalance to the exercise arm. By the same token, as the user passes rearward through the gravitational centerline, there is no appreciable drop off in resistance felt because of the balanced distribution of weight on each side of centerline  56 . 
   This machine fully supports the exerciser throughout the exercise movement so that they do not have to worry about balance and coordination, unlike a free weight exercise. As seen in the drawings, the lower torso and upper leg region is supported on the seat, the upper torso is supported by the back rest while the lower leg region is supported by the foot rest. The exercise arm and user support are linked to one another to self-align throughout the exercise movement, so that the handles can be angled for a more comfortable start and finish position. Because the exercise arm travels in fixed rotation about its pivot, the path of the user engaging handles relative to the user support is predetermined, and is designed to reduce the risk of injury and limit stress to the muscles, tendons, ligaments, and joints. 
     FIGS. 7 and 8  illustrate a machine similar to that of  FIGS. 1 to 6 , but replacing the weight stack with hand-loaded weight plates  60 . Apart from the exercise resistance, the machine of  FIGS. 7 and 8  is identical to the previous embodiment, and like references have been used for like parts as appropriate. In this embodiment, the base  62  of the user support is extended with an upwardly curved end portion  64 . Weight receiving pegs  65  extend in opposite directions from the end of base end portion  64 , for receiving a selected number of weight plates  60 . The base  62  rests on stop pad  66  on the frame base portion  20  when the machine is in the start position of  FIG. 7 . Movement of the exercise arm from the start position of  FIG. 7  into the raised, rearwardly rotated end position of  FIG. 8  rotates the user support rearwardly about pivot  32 , lifting the end portion  64  and weight plates  60  into the raised position. 
   The machine of  FIGS. 7 and 8  operate in essentially the same way as that of the previous embodiment, with the user, user support frame, and exercise arm following essentially the same motions as illustrated in  FIGS. 5 and 6 . It has the same advantages of closely mimicking the movement of an exerciser when performing a free weight shoulder press exercise, while supporting the user&#39;s body safely and securely in the proper orientation. The user support starts and finishes in substantially the same orientations as in the previous embodiment, and the rocking movement may increase the user&#39;s interest in the exercise. 
   In the embodiment of  FIG. 9 , the fixed length, single-piece connecting link  16  of  FIGS. 1 to 6  is replaced with an adjustable, two-piece connecting link having a first, tube portion  68  pivoted to the rear strut or portion  40  of the exercise arm for rotation about pivot  48 , and a second portion  70  telescopically engaged in the end of tube portion  68 . The second portion is pivoted to the upper end of the rear upright  27  of the user support via pivot  48 , in exactly the same way as link  16  of the previous embodiments. A releasable lock or snap pin  72  extends through an opening adjacent the end of tube portion  68  and into a selected opening  74  in the second portion  70  of the connecting link. Length of the connecting link can therefore be adjusted by releasing the lock pin  72  and moving the portion  70  into or out of the end of tube portion  68  until the desired length is reached, and then re-engaging the lock pin  72  in the aligned opening  74 . Adjustment of the length of the connecting link allows the starting height of the exercise arm to be adjusted, as illustrated in dotted outline in  FIG. 9 , to adjust to the seated height of the user. All other parts of the machine in  FIG. 9  are identical to parts in the first embodiment, and like reference numerals have been used as appropriate. 
   An adjustable length connecting link may replace a fixed length connecting link in either of the two embodiments described above, and also in any of the embodiments described below which have fixed length, rigid connecting links. The machine of  FIG. 9  also operates in essentially the same way as that of the previous embodiments, with the user, user support frame, and exercise arm following essentially the same motions as illustrated in  FIGS. 5 and 6 , with the added advantage of allowing the user to adjust the handles to the optimum starting height. 
     FIGS. 10 and 11  illustrate another modification of the machine of  FIGS. 1 to 6 , in which a single or two-piece foot rest  75  is mounted on the stationary base  20  of the main frame, in front of the user support, replacing the traveling foot plate  30  of the previous embodiments. All other parts of the machine are identical to that of  FIGS. 1 to 6 , and like reference numerals have been used as appropriate. It can be seen that the stationary foot rest does not detract from the self-aligning benefits of the exercise arm, pivoted user support, and connecting linkage for ensuring that the user support and user pivot rearwards as the user pushes the handles upwardly from the start position of  FIG. 10  to the end position of  FIG. 11 . The movement of the user&#39;s upper body and arms with the stationary foot rest is identical to the movement when their feet are supported on the moving foot rest, as can be seen by comparison of  FIGS. 5 and 6  with  FIGS. 10 and 11 . Thus, stationary foot rests may be used to replace the moving foot rests in any of the above embodiments or the embodiments described below. 
     FIGS. 12 and 13  illustrate a shoulder press exercise machine  80  according to another embodiment of the invention. In this embodiment, the connecting link of the previous embodiments, which pulls the top of the user support rearwardly when the exercise arm is raised, is replaced with a connecting link arranged to push the base portion of the user support upwardly and rearwardly. Other parts of the machine are identical to those of the first embodiment, and like reference numerals have been used as appropriate. 
   As in the first embodiment, the machine  80  has a main frame with a base  20 , a rearwardly inclined rear upright strut  22 , and a weight stack housing  18  at the forward end of base  20 . The user support frame is also substantially the same as in the first embodiment, and is of substantially L-shape with a base  25  on which adjustable seat pad  26  is mounted, an upright  27  on which back pad  28  is mounted, and a foot plate or foot support  30  at the forward, downwardly curved end of the base  25 . The base  25  is linked to a weight stack (not visible in the drawings) within housing  18  via cable  50  extending around pulleys  54  and  55 , as in the first embodiment. However, in this embodiment, the exercise arm  82 , the connecting link  84 , and the pivot mount  85  for the user support are modified. 
   In the embodiment of  FIGS. 12 and 13 , the user support frame is pivotally mounted on a pair of generally triangular pivot brackets or plates  86  mounted on opposite sides of the rear end of the frame base  20  and extending upwardly and forwardly from the base. The user support frame is pivoted on the upper ends of plates  86  via pivot pin  88 . The exercise arm  82  has a first or rear portion  90  which is pivoted to the upper end of strut  22  via pivot  92  spaced from the rear end of portion  90 . As in the previous embodiments, the remainder of the exercise arm comprises a U-shaped member with a central portion  44  secured to the upper or forward end of the rear portion  90 , and a pair of arms projecting forward from central portion  44  on opposite sides of the user support, in the exercise start position of  FIG. 12 . The exercise arms each have a handle  45  at their end for gripping by a user. 
   The lower or rear end of the exercise arm rear portion  90  is pivotally connected to the rear end of the connecting link or arm  84  via pivot  95 . The connecting link  84  extends forwardly from pivot  95  through an elongate slot or opening  96  in the rear frame upright  22 , and is then pivotally secured to the underside of the user support frame via pivot  98 , which is spaced in front of the seat support pivot. 
   The start and end positions of  FIGS. 12 and 13  are exactly the same as the start and end positions of the first embodiment, as illustrated in  FIGS. 5 and 6 . In the start position, the handles  45  are in a lowered position corresponding to a location below a seated user&#39;s chin and in front of their shoulders, while the seat or user support is in a slightly rearwardly reclined position. In order to perform the exercise, the user pushes or presses upwardly while gripping handles  45 , rotating the exercise arm in a rearward or anti-clockwise direction about pivot  92 . At the same time, the connecting link  84  is pushed forward, pushing the user support and forcing it to rotate rearwardly about the pivot connection  88  to the main frame. In the end position, the handles  45  are located straight above the user&#39;s head and in line with the side centerline of the user&#39;s body, while the seat is rotated back into a more reclined position. As in the previous embodiments, the controlled seat start and end positions provide proper, supported positioning of the user&#39;s body at the start and end of the exercise, as well as throughout the exercise movement. The movement of the user support to track movement of the exercise arm maintains the ideal alignment relationship between the user and the user engaging means or handles on the exercise arms, replicating the natural, gradual rearward arcing arm movement in a traditional, free weight barbell exercise. 
     FIGS. 14 and 15  illustrate two possible variations in the exercise arm which provide multiple gripping positions. In the embodiment of  FIG. 14 , the one-piece, U-shaped arm of the previous embodiments is replaced by a cross bar  100  secured to the end of the rear portion  40  of the exercise arm, and generally L-shaped handle arms  102  which are each pivotally secured to a respective end of cross bar  100  via pivots  104 . The gripping ends or handles  105  of the handle arms in this case project outwardly, rather than towards the front end of the machine as in the previous embodiments. The pivotal connection allows the handle arms  102  to swing inwardly or outwardly, as indicated in dotted outline in  FIG. 14 , and can provide a converging exercise motion as the arms are pressed upward. The exercise arm of  FIG. 14  may be used in place of the exercise arms with fixed handles in any of the above embodiments or in the additional embodiments described below. In the alternative of  FIG. 15 , the straight cross bar  100  of  FIG. 14  is replaced with a U-shaped member  106  having L-shaped handles  108  in fixed attachment to opposite ends of member  106 . The L-shaped handles provide multiple grip or hand positions, so that the user can grip the handgrips in both inward and forward facing direction. The handle arrangements of  FIGS. 14 and 15  duplicate the hand/arm position of a standing military barbell press and the standing or seated dumbbell press, allowing the user&#39;s hands to grip the hand grips with their hands in either an inward facing or a forward facing direction, rather than just the inward facing direction as illustrated in  FIGS. 5 and 6 . However, regardless of whether the handles are as in  FIGS. 1 to 13  or as in  FIG. 14  or  15 , the same basic exercise movement is provided and the same muscles are exercised. 
     FIGS. 16 and 16A  illustrate another modified exercise machine  110  according to another embodiment, which differs from the preceding embodiments since the single piece exercise arm is replaced by a split, two-piece arm. This embodiment is otherwise identical to the first embodiment of  FIGS. 1 to 6 , and like reference numerals have been used as appropriate. As in the first embodiment, the main frame has a base  20 , a rearwardly inclined, rear upright  22 , a user pivot mount portion  24 , and a weight stack housing  18  at the forward end of the base  20 . The user support frame is also identical to the first embodiment, having a base  25  on which a height adjustable seat pad  26  is mounted, an upright  27  on which a back support pad  28  is mounted, and a foot support or plate  30  at the forward end of base  25 . The user support frame is pivotally mounted on the main frame pivot mount portion  24  via pivot mount  32 , and is linked to the weight stack via a cable and pulley assembly identical to the first embodiment. 
   In this embodiment, as noted above, the single exercise arm of the previous embodiments is replaced by separate exercise arms  112  for independent arm movement by the user. Each exercise arm  112  has a rear pivot bracket  114  pivoted at one end to the upper end of the rear frame strut  22  via pivot  115 , and an elongate arm portion having an inwardly curved rear end  116  secured to an intermediate point on the pivot bracket  114 , and a forwardly projecting portion  118  having a handle or hand grip  120  at its forward end. Each pivot bracket  114  is connected to the upper end of the user support upright  27  by a cable and pulley assembly. The cable and pulley assembly or linkage comprises a pulley  122  pivotally mounted on a pivot bracket  124  at the upper end of the user support upright  27 , and a flexible line or cable  125  reeved through the pulley  122  and connected to the upper ends of the exercise arm pivot brackets  114 . 
   When one or both of the exercise arms  112  is pressed upwards, the line  125  pulls the user support rearward about its pivotal connection  32  to the main frame, towards the rearwardly reclined end position of  FIGS. 16 and 16A . When both exercise arms  112  are in the lower, start position illustrated for the rearmost arm in  FIGS. 16 and 16A , the user support is in the less reclined, start position of  FIG. 5 . This arrangement provides equal resistance to each of the user&#39;s arms and provides a more balanced workout. It allows the user to work one arm at a time and requires more coordination when both arms are worked together. If only one arm is moved, the resistance is halved and the user support moves half of the distance towards the end position. If both arms are pressed upwards together, the user support is moved to the end position. The handles of  FIGS. 16 and 16A  may be replaced by the alternative handle arrangements of  FIG. 14  or  15 , if desired. 
     FIGS. 17 and 18  illustrate another modification of the machine of  FIGS. 1 to 6 , and like reference numerals have been used for like parts as appropriate. The main difference between this embodiment and that of  FIGS. 1 to 6  is that the direct pivotal connection of the connecting link  16  to the user support upright  27  is replaced with a linear slide connection. In this embodiment, a guide rail  126  is secured to the rear side of the user support upright  27 , and a linear slide member  128  is slidably mounted on the guide rail  126 . The connecting link  16  is pivoted at one end to the rear strut or portion  40  at pivot  46 , as in the embodiment of  FIGS. 1 to 6 , but the opposite end is pivoted to a mounting bracket  130  on the slide member  128 , via pivot  132 . 
   Again, the exercise start and finish position of  FIGS. 17 and 18 , respectively, is identical to that of  FIGS. 5 and 6 . In the start position of  FIG. 17 , the slide member  128  is at the lower end of the guide rail or track  126 , and the exercise arm is in the lowered, start position. As the exercise arm is pressed upwards, the slide member moves up the guide bar, forcing the user support to rotate rearward into the rearwardly reclined end position of  FIG. 18 . 
     FIGS. 19 to 21  illustrate a modified version of the machine of  FIGS. 1 to 6 , in which geared cams are used in place of the pivoted connecting link  16  to translate upward motion of the exercise arm into rearward rotation of the user support.  FIG. 21  is an enlarged view illustrating the interlocking gears of the connecting link of  FIGS. 19 and 20  in more detail. The parts are otherwise identical to the machine of  FIGS. 1 to 6 , and like reference numerals have been used as appropriate. 
   A first geared cam  134  with gear teeth extending along arcuate edge  135  is mounted on the rear strut or portion  40  of the exercise arm  15 , which in turn is pivoted to the upper end of the frame rear upright  136  at pivot  138 . In this case, the rear upright  136  extends substantially vertically and is not rearwardly inclined, as was the case with rear upright  22  of the first embodiment. A second geared cam  140  with gear teeth extending along arcuate edge  142  is mounted on the rear of the user support upright  27 . A matching geared sprocket  144  is rotatably mounted on pivot  143  on a rear portion of a mounting bracket  145  secured to a generally horizontal pivot mount portion  146  of the main frame. Teeth on the arcuate edges  135 ,  142  of the cams  134 ,  140 , respectively, mesh with teeth on the sprocket  144 , as best illustrated in  FIG. 21 . The user support frame  14  is also rotatably mounted on the mounting bracket  145  at pivot mount  148  at the forward end of the mounting bracket  145 , with the pivot connection being at an equivalent position on the user support frame  14  to the pivot connection  32  of the first embodiment. 
   The exercise movement in this case is also identical to that illustrated in  FIGS. 1 to 6  above, with the same general start and finish position for the user, user support frame, and exercise arm. In this case, the geared cams  134  and  142  and the sprocket  144  start in the position illustrated in  FIGS. 19 and 21 . As the exercise arm handles  45  are pushed upward, the geared cam  134  rotates in the direction of the arrow in  FIG. 21  about its pivotal connection  138  to the main frame. This causes the geared sprocket  144  to rotate in a clockwise direction about pivot  143 , as also indicated by the arrow on the sprocket in  FIG. 21 . This, in turn, causes the geared cam  140  on the user support to rotate anti-clockwise in the direction of the arrow in  FIG. 21 , forcing the user support to rotate rearward about pivot connection  148  into the end position of  FIG. 20 . 
     FIGS. 22 and 23  illustrate another modified exercise machine  150  which has a modified connecting linkage between the user support and exercise arm. The machine of  FIGS. 22 and 23  is otherwise similar or identical to that of  FIGS. 1 to 6 , and like reference numerals have been used for like parts as appropriate. The exercise movement in this case is also identical to that of  FIGS. 1 to 6 , with the user, user support, and exercise arm adopting the same positions as illustrated in  FIGS. 5 and 6  in the exercise start and finish positions. 
   In the embodiment of  FIGS. 22 and 23 , the main frame has a rear upright  152  which is modified in shape to have a rearwardly curved end portion  154 . The exercise arm  155  is pivotally connected to the main frame via pivot brackets  156 , which are pivotally secured to the rear end of the frame rear upright  152  at pivot  158 , and which are connected to the mid point of a U-shaped member similar to the U-shaped member of  FIGS. 1 to 6 . However, the handles or hand grips  160  of the U-shaped member are bent at a greater angle to the remainder of the handle arms than the handles of the first embodiment, as can be seen in the drawings. The user support  14 , which is substantially identical to that of the first embodiment, is pivotally supported via pivot  162  on the upper ends of spaced pivot mounting brackets  164  secured to the main frame. 
   A connecting link or bar  165  is pivoted at one end to the lower ends of the pivot brackets  156  via pivot  166 , and extends in a forward direction through an opening  167  in the rear upright  152  and between the pivot mounting brackets  164 . The forward end of the link  165  is pivoted to a rolling wedge member  168  at pivot  170 . The rolling wedge member has a first pair of rollers  172  in rolling engagement with a track or guide  174  on the frame base member  20 , and an upper roller  175  in rolling engagement with an inclined guide or track  176  located on the undersurface of the user support frame at the junction between the base  25  and upright  27 . This linkage is similar to that described in co-pending application Ser. No. 10/195,665 filed Jul. 12, 2002, the contents of which are incorporated herein by reference. 
   As illustrated in  FIG. 22 , in the start position, the rolling wedge  168  is located towards the rear end of the guide track  174 , and the exercise arm  155  is in the lowered, start position which is just below the chin and in front of the shoulders of a user seated on the user support seat pad  26  with their back against back pad  28 . As the exercise arm is pushed upward to the finish position of  FIG. 23 , the lower end of the pivot brackets  156  pivots inwardly in an anti-clockwise direction about pivot  158 , simultaneously pushing the connecting link  165  forward. The opening  167  in the frame upright  152  is elongated to permit this motion. The connecting link  165  in turn pulls the rolling wedge  168  forward along tracks  174  and  176 , forcing the user support to rotate rearward into a more rearwardly inclined position. Thus, the exercise movement in this embodiment is exactly the same as in the previous embodiments, and the combined exercise arm and user support movement provides a self-aligning exercise motion that allows the user to start with their hands slightly forward of their shoulders, yet finish directly overhead with their arms in line with the side centerline of their body. 
     FIGS. 24 to 26  illustrate an exercise machine  180  according to another embodiment, which has a modified connecting linkage between the exercise arm and the user support. Other parts of the machine are the same as in previous embodiments, and like reference numerals have been used for like parts as appropriate. 
   In this case, the user support pivot mount is identical to that of  FIGS. 22 and 23 , comprising a pair of spaced pivot mounting plates or brackets  164 , with the user support pivotally mounted at the upper, forward ends of the plates via pivot pin  162 , located on the upright  27  of the user support adjacent the junction with the user support base  25 . The exercise arm  155  is also identical to the previous embodiment, having pivot brackets  156  and a U-shaped arm with a central portion secured to the upper ends of pivot brackets  156 , and angled handles  160  at its forward ends. However, in this case, the lower end of the pivot brackets are pivotally mounted at the upper end of the frame rear upright  22  via pivot  182 , and the brackets  156  are linked to the user support via a sliding linkage system  184 , which is illustrated in more detail in  FIG. 26 . This sliding linkage system is similar to the one described in co-pending application Ser. No. 10/171,236 filed Jun. 12, 2002, the contents of which are incorporated herein by reference. 
   The sliding linkage system  184  includes a guide bar  185  mounted on top of the base section  20  of the main frame, and acting as a runner for a slide member  186 , which may be a linear bearing, wheel, or the like. A connecting link  188  is pivotally connected at its first end to the slide member via pivot  190 , and at its second end to the underside of the elongated base section  25  of the user support via pivot  192 . The exercise arm  155  is connected to the slide member  186  by a cable and pulley system comprising a cable  194  having a first end anchored to the slide member, and extending around a first pulley  195  on the base  20  of the frame at a location spaced in front of the guide bar  185 , then back through the base  25  and around a pulley  196  mounted between the pivot mounting brackets  164 , and then around the double pulleys  198 , 199  before being anchored to the pivot brackets  156  of the exercise arm  155  at a location in front of the exercise arm pivot  182 . 
   As illustrated in  FIG. 24 , in the start position of the exercise arm and user support, the slide member  186  is at the rear end of the guide bar  185 . The user sits on the user support with their hands gripping handles  160 , and then pushes upwardly to rotate the exercise arm  155  upwardly and rearwardly about pivot  182  into the finish position of  FIG. 25 , in which the user&#39;s arms extend straight above their head and in line with the side centerline of their body. At the same time, upward movement of the exercise arm translates into forward movement of the slide member  186 , since the cable  194  is also pulled up and therefore pulls the slide member forwards. This causes the connecting link  188  to pivot about its connection to the slide member and user support. This action forces the user support to lift and rotate rearward about its pivot connection  162  to the main frame. Thus, the user support tracks movement of the exercise arm in exactly the same path as the previous embodiments, guiding and supporting the exerciser to maintain the proper body positioning and alignment throughout the exercise. 
     FIGS. 27 and 28  illustrate another modified shoulder press exercise machine  200  in which the user support pivot mount and the connecting link between the exercise arm and user support are modified. Other parts of the machine  200  are identical to those in previous embodiments, and like reference numerals have been used for like parts as appropriate. 
   In this embodiment, the main frame  12  and user support  14  are identical to the first embodiment, while the exercise arm  155  is similar to the embodiments of  FIGS. 22 to 25 . Main frame  12  has a base  20  with a rearwardly inclined, rear upright  22  and a weight stack housing  18  at its forward end. The exercise arm  155  has a first rear or lower portion comprising a pair of pivot plates or brackets  156  similar to  FIGS. 22 to 25 , and a U-shaped forward portion having a central region secured to the upper ends of the pivot brackets  156 , with a pair of forwardly projecting handle arms having suitably angled handles  160  at their forward ends. The lower ends of brackets  156  are pivotally mounted at the upper end of upright  22  via pivot  182 , as in the previous embodiment. User support frame  14  has a base  25  on which seat pad  26  is adjustably mounted, a rear upright  27  on which a back pad  28  is mounted, and a foot plate or support  30  at the forward end of base  25 . The base of the user support frame is linked to the weight stack via a cable and pulley system as in the first embodiment. 
   The user support is secured to a round cam  202  which in turn is pivotally mounted on a pivot mount  204  on the base  20  of the main frame via pivot  205 . This replaces the direct pivot mount of the user support as in the previous embodiments. The exercise arm  155  is linked to the round cam  202  via a cable and pulley system comprising a cable  206  extending from anchor  208  on the exercise arm pivot brackets  156 , around a double pulley device  210  on the rear upright strut  22  of the main frame, and then reeving around a pulley  212  at the junction between strut  22  and base  20  before extending to an anchor  214  on the round cam. 
   The start position of the machine  200  is illustrated in  FIG. 28 . As in the previous embodiments, the user sits on the user support seat in the start position, and grips the handles  160  which are positioned just in front of his or her shoulders. They then push the handles, and thus the exercise arm  155 , upwardly and rearwardly about pivot  182 . This in turn pulls on cable  206 , which forces the round cam  202  to rotate in an anti-clockwise direction, causing the user support  14  to pivot rearward into the end position of  FIG. 27 . Again, the exercise movement is substantially identical to the previous embodiments, with the user supported in the proper orientation throughout the exercise and aligned to the position of the exercise arm throughout the entire travel path. 
   In the embodiment of  FIGS. 29 and 30 , the exercise resistance or load is linked to the exercise arm, rather than to the user support as in all the previous embodiments. The exercise resistance, whether a weight stack as in  FIGS. 29 and 30 , weight plates, or other type of resistive load, in any of the previous embodiments may also be linked to the exercise arm rather than the user support, if desired. The other parts of the machine of  FIGS. 29 and 30  are the same as in one or more of the previous embodiments, and like reference numerals are used for like parts as appropriate. 
   The main frame  12  and user support  14 , as well as the majority of the exercise arm  15  and the connecting link  16  between the exercise arm and user support, are the same as in the first embodiment of  FIGS. 1 to 6 , while the user support pivot mount comprises spaced pivot brackets  86  as in the embodiment of  FIGS. 12 and 13 , with a pivot connection  88  between the upper ends of the pivot brackets and the underside of the user support. However, a pair of extended pivot brackets  215  are mounted on opposite sides of the rear strut  40  of exercise arm  15 . The pivot brackets  215  have a downwardly extending portion  216  linked to the weight stack via a cable and pulley system comprising a cable  218  extending from an anchor  219  on the rear frame strut  22 , around a pulley  220  rotatably mounted between the end portions  216  of the exercise arm pivot brackets  215 , and then around pulleys  222  mounted between the user support pivot mount brackets  86  before extending through the base  20  of the main frame and into the weight stack housing. 
   The start position of the modified machine is illustrated in  FIG. 29 , and is equivalent to the start positions of the previous embodiments, with the user support  14  in a slightly rearwardly reclined orientation, and the exercise arm  15  in a lowered position with the handles  45  at a location which would be just in front of the shoulders and below the chin of a user seated on the user support with their back resting against back pad  28 . The user pushes up on the handles  45  in order to perform the exercise, rotating the exercise arm upwardly and rearwardly, and pulling the resistive cable  218  so as to lift the selected weights in the weight stack. At the same time, movement of the exercise arm  15  is linked to the user support  14  by the pivoted connecting link  16  in exactly the same way as the first embodiment, so that the upright  27  is pulled back and the user support is forced to rotate rearwardly about pivot  88  into the more rearwardly reclined position of  FIG. 30 . This modified exercise machine therefore moves in exactly the same way as in the previous embodiments and has the same advantages of proper support of the user throughout the exercise movement, while accurately simulating the upper body motion of a free weight shoulder press exercise. 
     FIGS. 31 and 32  illustrate a modified exercise machine  224  which is similar to the machine of  FIGS. 29 and 30  but replaces the weight stack exercise resistance with a plate-loaded resistance. This is similar to the difference between the embodiment of  FIGS. 1 to 6  and that of  FIGS. 7 and 8 , except that those embodiments have the exercise resistance associated with the user support, whereas this embodiment and that of  FIGS. 29 and 30  have the exercise resistance associated with the exercise arm. Other parts of the machine  224  are identical to parts in one or more previous embodiments, and like reference numerals have been used for like parts as appropriate. 
   In this embodiment, the exercise arm  15  has a pair of downward extension plates  225  extending downwardly from rear strut  40  in the start position of  FIG. 31 . Plates  225  are pivoted to the upper end of frame rear upright  22  (which is vertical rather than rearwardly inclined) at pivot  42 , and project downwardly from the pivot  42  on opposite sides of the strut  22 . Weight supporting pegs  226  project in opposite directions from the ends of plates  225 , and a selected number of weight plates  228  can be loaded on the pegs  226 . 
   In the start position of  FIG. 31 , the weight plates  228  rest in a lowered position near the ground while the forward end (foot plate  30 ) of the user support rests on stop pad  38 . The positions of the exercise arm  15  and user support  14  are identical to the start positions of these parts in the previous embodiments. Again, the seated user grips the handles  45  and pushes upwardly, rotating the exercise arm  15  upwardly and rearwardly, and lifting the weight plates  228  into the raised position of  FIG. 32 . At the same time, connecting link  16  pulls the upper end of the user support rearwardly, rotating the user support about pivot  32  into the more rearwardly reclined end position of  FIG. 32 . Again, in this position, the user&#39;s arms extend straight above their head in line with the side centerline of their body, mimicking the upper body end position of a free weight shoulder press exercise. This modified machine therefore also has all the advantages described above in connection with the previous embodiments. 
     FIGS. 33 and 34  illustrate a modified shoulder press exercise machine  230  similar to the machine of  FIGS. 27 and 28  but with a different linkage to the exercise resistance. Other parts of this machine are identical to the embodiment of  FIGS. 27 and 28 , and like reference numerals have been used as appropriate. In this embodiment, the single round cam  202  of  FIGS. 27 and 28  is replaced by a double cam, comprising a first, larger user support cam  232  and a smaller cam  234  which is linked to the exercise arm. At least the first, user support cam is mounted on rotating pivot shaft  205 , while the second, smaller cam may be attached to the user support cam  232 , or may be fixedly attached to the same pivot shaft  205  as the user support cam, so that the cams  232 , 234  rotate in unison. 
   The user support  14  is fixedly attached to the user support cam  232 , and the cam  232  in turn is linked to the weight stack in housing  18  via a cable  233  extending from anchor  236  on the cam  232 , and around a pulley  238  on the base  20  of the main frame, before extending into the weight stack housing and linking to the weight stack in a conventional manner. The exercise arm  155  is linked to the second, smaller cam  234  via a cable  206  extending from an anchor point  208  on the brackets  156 , around a double pulley device  210  on the rear upright strut  22 , around a further pulley  212  mounted at the junction between the rear strut  22  and base  20  of the main frame, and then connecting to an anchor  246  on the smaller cam  234 . 
   The start and finish positions of the machine  230  are illustrated in  FIGS. 34 and 33 , respectively, and it can be seen that the exercise arm and user support correspond in orientation and relative positions to the start and finish positions of all of the previous embodiments. The user seated on user support  14  in the start position of  FIG. 34  pushes up on handles  160 , rotating the exercise arm  155  upwardly and rearwardly about pivot  182 . This pulls on cable  206 , rotating the smaller cam  234  in a counter-clockwise direction and causing a similar rotation of the larger cam  232 , such that the user support  14  is rotated about the pivot axis of pivot shaft  205  into the more rearwardly reclined, end position of  FIG. 33 . Rotation of cam  232  in turn pulls the resistive cable  233 , lifting the selected weights in the weight stack. 
     FIGS. 35 to 38  illustrate a shoulder press exercise machine  250  according to another embodiment, in which the rotatably mounted exercise arm of the previous embodiments is replaced with a linear movement exercise arm. Machine  250  has a main frame with a base  252 , a vertical rear strut  254 , an inclined strut  255  extending rearwardly from the base  252  across the upper end of rear strut  254 , and a weight stack housing  256  at the forward end of the frame. A pair of guide bars  258  are mounted on the upper side of the inclined strut  255 , and an exercise arm  260  comprising a U-shaped member has a central portion  262  secured to linear bearings  264  which are slidably mounted on guide bars  258 . The linear bearings  264  may be replaced with wheels, bushings, or any other linear movement device known in the art. Exercise arm  260  has handles  265  at its ends which are bent at an appropriate angle for gripping by a user  266  as illustrated in the start position of  FIG. 37 . 
   Machine  250  has a user support  14  substantially identical to the previous embodiments, and like reference numerals have been used as appropriate. User support  14  is generally L-shaped with a base  25  on which a seat pad  26  is adjustably mounted, and an upright  27  on which back pad  28  is mounted. A pivot bracket  268  is mounted on the inclined frame strut  255  adjacent the lower ends of guide bars  258 , and the user support is pivotally mounted on pivot bracket  268  via pivot pin  270 . The base  25  of the user support is linked to the weight stack via a cable and pulley system identical to that of  FIGS. 1 to 6 , as best illustrated in  FIGS. 36 to 38 . A pulley  272  is mounted at the upper end of the user support upright  27 . A cable  274  has a first end connected to the sliding linear bearings  264  of the exercise arm, and is reeved around a series of pulleys  275 , 276 , 277  mounted on the inclined strut  255  of the main frame, then around pulley  272  on the user support, before being connected at its second end to an anchor  278  at the upper end of the inclined strut  255 . 
     FIG. 37  illustrates the user  266  in a start position seated on the user support seat pad  26  (which can be adjusted to the appropriate height) and leaning against back pad  28 , with their hands gripping the exercise arm handles  265  at a position corresponding to the start position for a free weight shoulder press exercise. The dotted line  280  represents the side centerline of the user. The user&#39;s hands are positioned slightly in front of the shoulder in the starting position. As the exercise arm  260  is pushed upward by the user, the linear bearings  264  slide upwardly and rearwardly along tracks or guide bars  258 , pulling cable  274 , which in turn pulls on pulley  272  at the upper end of the user support, pulling the user support  14  rearward to rotate about its pivot connection  270  into the end position of  FIG. 38 . 
   In the end position of  FIG. 38 , the user&#39;s hands are positioned above their head and in line with the side centerline  280  of the user&#39;s body. This machine therefore provides the same self-aligning movement and proper positioning of the user support and user with a linear movement exercise arm as it does with a rotational movement exercise arm. 
   Although in this embodiment the resistance is supplied by a weight stack which is linked to the user support via a cable and pulley system, it may alternatively be in the form of hand-loaded weight plates mounted on receiving pegs, as in the embodiment of  FIGS. 7 and 8 . Other variations could have different types of exercise resistance, and exercise resistance connected directly or indirectly to the exercise arm  260 . 
     FIGS. 39 and 40  illustrate a shoulder press exercise machine  281  according to another embodiment, in which the user support pivot mount and exercise arm pivot mount are modified to change the movement of the user support, such that it travels in a partially forward direction while pivoting into a more rearwardly reclined orientation. The user support  14  of machine  280  is similar to that of the previous embodiments, and like reference numerals have been used as appropriate. The main frame has a base  282  with a weight stack housing  284  at its forward end, as in the first embodiment, but the rear end of the frame is modified. The frame has a rear strut  285  which has a first portion which is substantially vertical, with a very slight rearward inclination, and a forwardly angled upper portion. A second upright strut  286  is inclined rearwardly from a location spaced in front of the rear strut  285 , and has a bent rearwardly extending upper portion  288 . An exercise arm  290  is pivotally mounted on the rear end of strut upper portion  288  for rotation about pivot  292 . User support  14  is pivotally connected to the upper end of the rear strut  285  at the upper end of upright or backrest section  27 , via pivot  294 . 
   The exercise arm  290  has a pair of rear or lower pivot brackets  295  and a U-shaped member having a central portion secured to the upper ends of pivot brackets  295  in a similar manner to the embodiment of  FIGS. 12 and 13 . Forwardly extending handle portions of the U-shaped member extend on opposite sides of the user support  14  in the start position of  FIG. 39 , and have handles or hand grips  296  at their forward ends. The exercise arm pivot  292  is located in a central region of the exercise arm pivot brackets  295 . A connecting link  298  is pivotally connected at one end to the lower ends of the exercise arm pivot brackets  295  via pivot  300 , and is pivotally connected at its opposite end to the user support backrest or upright  27  at a location spaced below the user support pivot  294 , via pivot  302 . The user support  14  is linked to the weight stack in housing  284  via a cable and pulley assembly, comprising cable  303  having one end connected to cable anchor  304  on the underside of the user support at the junction or bend between the upright  27  and base  25 , and reeved around a pulley  305  on the frame base  282  before extending through the base and into the housing  284 , where it is linked to the weight stack. 
   In this machine, the start position of  FIG. 39  puts the user support  14  and the hand grips  296  of the exercise arms in the same relative orientations and positions as in the previous embodiments. When a user seated on the user support pushes the exercise arm upward, so that it rotates rearwardly about pivot  292 , the lower end of the exercise arm pivot bracket is rotated forwardly, pushing the connecting link  298  forward so that it pivots in an anti-clockwise direction about its pivot connection  294  to the main frame. This movement raises the seat pad  26  upward and tilts the back pad  28  rearward, effectively duplicating the exercise arm and user support positioning of the previous embodiments. This movement also pulls on the resistive cable  303 , lifting the selected weights in the weight stack. The exercise resistance may alternatively be supplied by plates loaded on receiving pegs mounted to the user support as in  FIGS. 7 and 8 , or the resistance could be attached to the exercise arm  290  as in the embodiment of  FIGS. 29 and 30  or that of  FIGS. 31 and 32 . 
   This embodiment has all of the advantages of the self-aligning movement of the previous embodiments, allowing the user to start the exercise in a position which duplicates the start position of a free weight shoulder press and to move from that position to a finish position with their arms directly overhead and their hands aligned with the side centerline of their body, with the user&#39;s back being supported throughout the movement and not involved in the exercise. However, this embodiment does not have a user support pivot located beneath the user&#39;s body, unlike the previous embodiments, and thus does not have portions of the combined weight of the user and user support on both sides of the gravitational centerline of the pivot. Although there is some starting resistance due to the weight of the user and user support, the combined weight remains forward of the gravitational centerline throughout the exercise, so that there is no appreciable resistance drop off. 
     FIGS. 41 to 44  illustrate a shoulder press exercise machine  310  according to another embodiment, which has a similar user support pivot mount position to the previous embodiment. The main frame  12  user support  14  in this case are similar or identical to the previous embodiments, and like reference numerals have been used as appropriate. This machine also has an exercise arm  290  identical to that of the previous embodiment, although mounted slightly differently on the main frame. In this embodiment, the exercise arm pivot brackets  295  are pivotally mounted on the upper end of the frame rear upright  22  via pivot  312  which is spaced from the lower ends of the brackets. 
   A multiple arm linkage system  314  pivotally links the lower ends of the exercise arm brackets  295  to the user support and to the main frame. The linkage system  314  includes a first connecting link  315  having one end pivotally connected to the upper end of the user support upright  27  at pivot  316 , and a second, smaller connecting link  318  which is generally L-shaped and has one end pivoted via pivot  319  to a pivot bracket  320  mounted on the user support upright  27  at a location spaced below pivot  316 . A third link  322  is pivotally connected to the lower end of the exercise arm brackets at pivot  324 , and has a second end pivoted to the end of the second connecting link  318  at pivot  325 . Both the first and second links are also pivotally connected to the main frame via pivot brackets  326  mounted on the rear upright  22 . The second end of the first connecting link  315  is pivoted to brackets  326  via pivot  328 , while the second link is pivotally connected to brackets  326  via pivot  330  at the elbow or the intersection of its two legs. 
     FIGS. 41 and 43  illustrate the start position of the machine, which has the exercise arm and user support in an equivalent position to the previous embodiments. The user grips handles  296  and pushes the front end of exercise arm  290  upwards, rotating the arm  290  about pivot  312  in an anti-clockwise direction. This moves the lower end of the exercise arm brackets  295  forward, pushing the third connecting link  322  forward, which in turn pushes the second link  318 , causing it to rotate about its pivot connection  330  to the main frame. Because of the L-shape of the second link  318 , this rotation causes the user support  14  to lift upward. At the same time, the first connecting link  315  between the upper end of the user support and the main frame controls movement of the back rest or upright  27  of the user support, causing it to rotate rearward. The end position of the user support is illustrated in  FIGS. 42 and 44  and involves upward movement of the user support, along with rearward rotation of the upright  27  into a more reclined position. The user support base  25  is linked to the weight stack via a cable and pulley system similar to the first embodiment, with a cable  332  extending from the underside of base  25 , around a pulley  334  on the frame base  22 , and into the weight stack housing where it is suitably linked to the weight stack. Again, other types of exercise resistance such as peg mounted weight plates may alternatively be used, and the load may be linked to the exercise arm rather than the user support if desired. 
   The end position of the user support relative to the user engaging handles  296  of the exercise arm is equivalent to the end positions of the previous embodiments, putting the user in a position in which their arms are extended straight overhead and their hands are in line with the side centerline of their body. As in the embodiment of  FIGS. 39 and 40 , this machine provides the proper positioning of the user&#39;s body in the start and end position, as well as throughout the exercise movement. The combined exercise arm and user support movement provides a self-aligning exercise motion which simulates the upper body motion when performing a free weight shoulder press exercise. 
   Each of the embodiments of  FIGS. 1 to 44  has a pivoting or rocking user support that continuously and automatically self-aligns to the movement of the exercise arm throughout the entire exercise motion, thereby maintaining an ideal alignment relationship between the exerciser positioned on the user support and the user engaging means or handles on the exercise arm. The rocking movement of the user support makes the exercise more fun to perform. Additionally, this design provides the proper starting and finishing alignment between the user and machine for an exercise which simulates a free weight, barbell or dumbbell shoulder press exercise. The combined motion of the user support and exercise arm replicates the natural, small rearward arcing motion an exerciser would go through when performing a free weight shoulder press exercise. This combined motion of the user support and exercise arm also provides a safer and more natural feeling exercise motion, and the user&#39;s back is fully supported throughout the exercise so that it is not involved in the exercise. The machines of this invention are an improvement over the exaggerated and unnatural arcing movement of prior art shoulder press exercise machines. 
   In most of the embodiments described above, apart from those of  FIGS. 39 to 44 , the user support pivot is positioned behind the hips of the user so that a portion of the user and user support is positioned on both sides of the gravitational center line of the pivot throughout the exercise motion. This limits the effect of the user&#39;s body weight on the exercise resistance and provides counter-balancing to prevent or reduce resistance drop-off. 
   Each of the above shoulder press machines places the user in a start position with their hands gripping the exercise arm handles slightly forward of their shoulders, and an end position with their hands directly overhead and inline with the side centerline of their body. This is essentially the same as the start and finish position of a free weight shoulder press exercise. The user is properly braced with a secondary support or back support during the exercise, and does not have to adjust their body position during the exercise motion, as in some prior art machines. The machines all have user supports which are low to the ground and easily accessible for mounting and dismounting, and do not require the user to climb onto a vertically moving platform or up and down steps in order to reach a user support. 
   Because the user support aligns to the position of the exercise arm throughout the exercise movement, the handle or user engaging or gripping device can be angularly positioned to reduce strain on the wrist in the starting position, and maintains proper positioning and alignment of the hands and wrists throughout the exercise. The primary and secondary user supports (user support seat and user support back rest) are in fixed alignment to each other and travel together through the same range of motion, and rotate together about a fixed pivot. 
   It should be understood that the different elements used in the various embodiments described above may be mixed and interchanged. Any of the above linkages between the user support and exercise arm may be used in any of the designs described above. The foot rest could be stationary or move with the user support. The user supports (seat pad, back pad and/or foot rest) may be fixed or adjustable. The exercise arms may be one piece (dependent) or two piece (independent), and may be unidirectional or bidirectional. The connecting links may be adjustable in length, solid links may be replaced with flexible links, and the links may be arranged either to push or pull in order to force rotation of the user support. Different handles may be used without affecting the operation of the machine. The cable and pulley system linked to a weight stack may be replaced with weight plates mounted on pegs. Other types of resistance known in the art, such as hydraulic, pneumatic, or electromagnetic resistance, or elastic bands, may be used in place of the weight stack or weight plates. Cable linkages could be replaced by belts, ropes, chains, or the like, and pulleys may be replaced by sprockets. Any of the various designs could have the resistance associated with any of the moving parts of the machine, i.e. the user support, exercise arm, or connecting link. 
   In summary, the shoulder press exercise machine of this invention provides an exercise simulating a free weight (barbell or dumbbell) shoulder press exercise which is fun, more comfortable, and safe to use. By forcing the user support to move in a self-aligning motion with the exercise arm, the exaggerated and unnatural arcing movement found in prior art shoulder press machines is avoided, and replaced with a smaller, natural arc similar to that an exerciser would encounter when performing shoulder press exercises with free weights. The reclined seat places the user in a proper starting position and the primary and secondary user supports keep the user in a safe, stable position throughout the exercise. At the same time, the rocking motion of the user support makes the exercise more fun to perform. By adding motion to the user support, performing the exercise is more enjoyable and the user&#39;s interest in the workout increases. This may help to convince the user to exercise more regularly. 
   All of the machines have a user engagement device or exercise arm with a linkage linking movement of the exercise arm to movement of the user support. A load provides resistance to movement of the user support, the exercise arm, and/or the connecting link. Additionally, each design has a primary user support or seat, as well as at least one secondary user support for another part of the user&#39;s body. The machines are configured to produce the proper starting and finishing arm/hand positions for the respective shoulder press exercises. 
   In the above embodiments, the pivoting seat and backrest (user support) continuously and automatically self-aligns to the movement of an exercise arm throughout the entire exercise motion. This combined movement maintains a desirable alignment relationship between the exerciser, positioned on the user support, and the user engaging means (handles) on the exercise arm. 
   The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly limited by nothing other than the appended claims.