Title:
Weight Training Apparatus and Method
Kind Code:
A1


Abstract:
A weight training apparatus includes a track rotatably connected to a frame for rotation about a first axis to define a first moment arm. A weight is carried by the track at preselected positions for providing torque. A movement arm is pivotally connected to the frame to define a second moment arm. A coupling between the movement arm and the track causes a rotating of the track in response to a rotation of the movement arm. An angular movement of the second moment arm through a second arc length results in an angular movement of the first moment arm through a first arc length, wherein the second arc length is greater than the first arc length for all rotations of the movement arm and the track. The weight thus moves more slowly than the resistance arm.



Inventors:
Sencil, Philip M. (Commerce City, CO, US)
Application Number:
11/858325
Publication Date:
03/27/2008
Filing Date:
09/20/2007
Assignee:
MEDX CORPORATION (Altamonte Springs, FL, US)
Primary Class:
International Classes:
A63B21/06
View Patent Images:



Primary Examiner:
TECCO, ANDREW M
Attorney, Agent or Firm:
CARL M. NAPOLITANO, PH.D. (ORLANDO, FL, US)
Claims:
That which is claimed is:

1. A weight training apparatus comprising: a frame; a track rotatably connected to the frame and pivotal about a first axis, a resistance block carried by the track at a relocatable preselected position along the track, wherein the resistance block and the track form a resistance block assembly having a center of gravity; a movement arm pivotal about a second axis, the movement arm having a user engagement portion for applying a force to the movement arm; a coupling connecting the movement arm to the resistance block assembly for rotating the track about the first axis in response to rotation of the movement arm about the second axis, wherein an angular movement of the center of gravity of the resistance block assembly through a first arc length results from an angular movement of the user engagement portion through a second arc length, and wherein the second arc length is greater than the first arc length for all rotations of the movement arm and the track, the center of gravity of the resistance block assembly thus moving more slowly than the user engagement portion.

2. An apparatus according to claim 1, further comprising a fixed link fixedly attached to the track, wherein the coupling is connected to the fixed link.

3. An apparatus according to claim 1, further comprising a keeper securing the resistance block to the track at the preselected position.

4. An apparatus according to claim 2, wherein the keeper comprises a drive mechanism operable with the resistance block for movement thereof.

5. An apparatus according to claim 4, wherein the drive mechanism comprises a threaded shaft, and wherein rotation of the shaft results in a linear movement of the resistance block along the track.

6. An apparatus according to claim 1, wherein the resistance block is carried by the track so as to distribute its weight such that the center of gravity of the resistance block assembly is generally aligned with a longitudinal axis of the track.

7. An apparatus according to claim 1, wherein the resistance block comprises a plurality of weight blocks.

8. An apparatus according to claim 1, wherein the resistance block is moveable to locations along the track from one side of the first axis to an opposing side thereof for providing positive and negative torque thereto.

9. An apparatus according to claim 1, further comprising a wheel assembly operable between the resistance block and the track, the wheel assembly enhancing a slidable movement of the resistance block along the track from the preselected position to a second preselected position.

10. An apparatus according to claim 1, wherein the coupling comprises a resistance modulator for modifying a resistance felt by the user engagement portion at various locations within the second arc length for a fixed preselected position of the resistance block on the track.

11. An apparatus according to claim 10, wherein the resistance modulator comprises at least one of a cam, a rod, and a belt.

12. An apparatus according to claim 1, wherein the movement arm comprises adjustable means for slidable movement of the resistance arm toward and away from the second axis of rotation, thus allowing a length modification to the second moment arm.

13. An apparatus according to claim 1, wherein the movement arm is pivotally connected to the frame, and wherein the user engagement portion includes a resistance arm attached generally perpendicular to the movement arm.

14. An apparatus according to claim 1, further comprising a linkage connecting the movement arm to the coupling.

15. An apparatus according to claim 14, wherein the linkage comprises a pulley assembly rotatably connected to the frame and a strap connected to the movement arm for operation of the coupling therewith.

16. An apparatus according to claim 1, further comprising a seat assembly operable with the frame, wherein the seat assembly comprises a base support and a back support.

17. An apparatus according to claim 16, wherein the movement arm is carried by the seat assembly.

18. An apparatus according to claim 2, wherein the fixed link comprises a lift bar fixedly attached to the track, wherein the lift bar includes opposing plates in spaced relation and dimensioned for permitting the resistance block to pass therebetween, the lift bar further including a link bar providing an attachment point for the coupling.

19. An apparatus according to claim 18, wherein the fixed link is pivotally attached to the track at a third axis.

20. A weight training apparatus comprising: a frame a track rotatably connected to the frame; a resistance block carried by the track at a preselected position thereon; a movement arm having a user engagement portion for applying a force thereto; and a coupling operably between the movement arm and the track for rotating the track in response to a movement of the movement arm, wherein a movement of the movement arm through a first length dimension results in an angular movement of the track through a second length dimension, and wherein the first length dimension is greater than the second length for all movements of the movement arm and the track, the resistance block thus moving more slowly than the movement arm.

21. An apparatus according to claim 20, wherein the second length dimension includes an arc length dimension.

22. An apparatus according to claim 20, further comprising a keeper securing the resistance block to the track at the preselected position.

23. An apparatus according to claim 22, wherein the keeper comprises a drive mechanism operable with the resistance block for movement of the resistance block along the track.

24. An apparatus according to claim 20, wherein the resistance block is carried by the track so as to distribute its weight such that a center of gravity of the resistance block is generally aligned with a longitudinal axis of the track.

25. An apparatus according to claim 20, wherein the resistance block is moveable to locations along the track for providing positive and negative torque thereto.

26. An apparatus according to claim 25, the resistance block is moveable along the track during a period wherein the user engagement portion is applying the force to the movement arm.

27. An apparatus according to claim 20, wherein the coupling comprises a resistance modulator for modifying a resistance felt by the user engagement portion for a fixed preselected position of the resistance block on the track.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/826,395 filed Sep. 21, 2006, the disclosure of which is hereby incorporated herein in its entirety by reference.

FIELD OF THE INVENTION

The present invention generally relates to the field of exercise machines, and more particularly to resistance and weight training exercise machines and related methods.

BACKGROUND OF THE INVENTION

A traditional weight machine generally includes a stack of weight blocks arranged in a vertical array and an engagement member to select a particular block lifts that block and all upper blocks. The use of a weight stack provides a relatively easy method to change the resistance for a particular exercise or a particular subject. However, the weight stack produces high frictional losses due to the required tracks and guide rods on either side of the blocks to control the movement of the selected blocks and ensure they do not become misaligned or disengaged. Most of the effort in friction reduction involves using lower friction bearing materials on the weight blocks starting with metal plane bearing material, plastic bearing material up to the low friction linear ball bearings. However, the high expense of linear ball bearings used for each weight block has resulted in few manufacturers migrating from the higher friction plane bearing methods. The present invention is directed to a need in the art to develop a weight resistance source for weight training machines providing reduced frictional losses while minimizing the associated expense.

SUMMARY OF INVENTION

In keeping with the teachings of the present invention, a weight training apparatus may comprise a track rotatably connected to a frame for rotation of the track about a first axis. A resistance block may be carried by the track at a preselected position for providing a preselected torque thereto. A movement arm may be pivotally connected to the frame for rotation about a second axis. The movement arm includes a user engagement portion for applying a resistive force to the movement arm. One embodiment may include a resistance arm for use as the user engagement portion. The resistance block and the track may be defined as forming a resistance block assembly having a center of gravity. A coupling between the movement arm and the assembly causes a rotating of the track about the first axis in response to a rotation of the movement arm about the second axis, wherein an angular movement of the center of gravity of the resistance block assembly through a first arc length results from an angular movement of the user engagement portion through a second arc length, and wherein the second arc length is greater than the first arc length for all rotations of the movement arm and the track. The center of gravity of the assembly thus desirably moves more slowly than the user contact portion.

Embodiments of the invention may include a keeper securing the resistance block to the track at the preselected position, wherein the keeper comprises drive means operable with the resistance block for movement thereof. The resistance block may be moved from one preselected position to another for one fixed weight training to another, or may be moved within a given weight training. By way of example the resistance felt by a user operating the movement arm may react to a first torque provided by the resistance block assembly during an eccentric movement and to yet another during a concentric movement. The drive means may comprise a threaded shaft, and wherein rotation of the shaft results in a linear movement of the resistance block along the track. Yet further, the drive means may comprise a crank for manually rotating the shaft or a drive motor for rotating the shaft.

In one embodiment, the resistance block is carried by the track so as to distribute its weight such that a center of gravity of the resistance block is generally aligned with a longitudinal axis of movement of the resistance block along the track. Embodiments may also include the resistance block having a plurality of weight blocks. The resistance block may be moved to locations along the track so as to provide positive and negative torque to the track. Yet further, a wheel assembly may be employed with the resistance block and the track for ease in sliding the resistance along the track from position to alternate position.

For embodiments of the invention, the coupling may comprises resistance modulating means for modifying a resistance felt by the resistance arm at various locations within the second arc length for a fixed preselected position of the resistance block on the track. By way of example, the resistance modulating means may comprise a cam, a rod, a belt, or a combination thereof. The fixed link may comprise a lift bar fixedly attached to the track, wherein the lift bar includes opposing plates in spaced relation for permitting the resistance block to pass therebetween. The lift bar may further include a link bar providing an attachment point for the coupling. Alternatively, the fixed link may be pivotally attached to the track at a third axis.

The movement arm may further comprise adjustable means for slidable movement of the resistance arm toward and away from the second axis of rotation, thus allowing a modification to the length of the second moment arm.

A seat assembly may be connected to the frame and may comprise a base support and a back support.

BRIEF DESCRIPTION OF DRAWINGS

Features and benefits of the present invention will become apparent as the description proceeds when taken in conjunction with the accompanying drawings and photos in which:

FIGS. 1 and 2 are front left and front right perspective views, respectively, of one embodiment of a weight training apparatus in keeping with the teachings of the present invention, the apparatus illustrated in one starting position;

FIG. 3 is a elevation view of the embodiment of FIG. 1;

FIG. 4 is a perspective view of the embodiment of FIG. 1 illustrating the apparatus in a weight lifting position;

FIG. 5 is a side view of the embodiment in FIG. 4;

FIG. 6 is a partial perspective view of a weight module portion of the embodiment of FIG. 1;

FIG. 7 is a top plan view of a weight module portion of the embodiment of FIG. 1;

FIG. 8 is a side view of the weight module portion of FIG. 7;

FIG. 9 is a rear view of the weight module of FIG. 7;

FIG. 10 is a perspective view of the weight module of FIG. 6 illustrating a resistance block in an alternate position along a track;

FIG. 10A is a perspective view of an alternate embodiment of a weight module;

FIG. 11 is a partial perspective view including a track and weight block operable along the track using wheels;

FIG. 12 is a front right perspective of a alternate embodiment of a weight training apparatus in keeping with the teachings of the present invention;

FIG. 13 is a rear perspective view of the embodiment of FIG. 12; and

FIG. 14 is a side view of the embodiment of FIG. 12.

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternate embodiments.

Referring initially to FIGS. 1-3, one embodiment of the invention may include a weight training apparatus 10 having a track 12 rotatably connected to a frame 14 at a first fulcrum 16 for rotation of the track about a first axis 18. A resistance block 20 is carried by the track 12. The resistance block 20 and the track 12 form a resistance block assembly 22 having a center of gravity 23. As will be clear to those of ordinary skill in the art, the center of gravity will generally be located within the block but is herein illustrated as viewed from a side or top for illustration purposes. A distance from the center of gravity 23 to the first axis 18 defines a first moment arm 24. The resistance block 20 may be located at a preselected position 26 for providing a preselected torque to the track. As will be further detailed, various positions along the track 12 are available for placement of the resistance block 20 depending upon the weight training exercise desired and thus torque to be provided. For the embodiment herein described by way of example, a movement arm 28 pivotally connected to the frame 14 at a second fulcrum 30 for rotation of the movement arm about a second axis 32. For the embodiment herein described by way of example with reference to FIG. 1, the movement arm 28 includes a resistance arm 34 at a user engagement portion of the movement arm. A distance from the resistance arm 34 to the second axis 32 defines a second moment arm 36. As is known in the art, such a resistance arm 34 may be padded for providing comfort to a user operating the apparatus 10. As will be further addressed later in this section, the movement arm 28 may not be carried by the frame 14 and may be attached to other assemblies forming a part of alternate embodiments of the weight training apparatus 10.

With continued reference to FIGS. 1-3, and to FIGS. 4 and 5, a coupling 38 between the movement arm 28 and a fixed link 13 attached to the track 12 causes a rotating of the track about the first axis 18 in response to a rotation of the movement arm 28 about the second axis 32. An angular movement 40 of the second moment arm 36 through a second arc length 42 results in an angular movement 44 of the first moment arm 24 through a first arc length 46, wherein the second arc length is greater than the first arc length for all rotations of the movement arm 28 and the track 12. The resistance block 20 thus moves more slowly than the resistance arm 34.

As illustrated herein by way of example with reference to FIGS. 6 and 7, the apparatus 10 may include a keeper 48 securing the resistance block 20 to the track 12 at the preselected position 26. The keeper 48 includes a drive mechanism 50 for moving the resistance block 20 along the track 12. The drive mechanism 50 as herein described by way of example, includes a threaded shaft 52. By rotating the shaft 52, there is a linear movement 54 of the resistance block 20 along the track 12. As herein described, the drive mechanism 54 may comprise a crank 56A for manually rotating the shaft or a drive motor 56 for rotating the shaft 52.

In one embodiment, and as illustrated with reference to FIGS. 8-9, the resistance block 20 is carried by the track 12 so as to distribute the weight of the resistance block uniformly above 58 and below 60 the track 12 such that the center of gravity 13 of the resistance block assembly 22 is generally aligned with a longitudinal axis 64 of the track 12, which for the embodiment illustrated herein by way of example is generally along the axis of the shaft 52. A plurality of weight blocks 66 permits ease in distributing the weight. As illustrated with reference to FIG. 10, the resistance block 20 may be moved to alternate locations 68 along the track 12 so as to provide positive and negative torque to the track, depending upon the location of the center of gravity 23 in relation to the first axis 18, by way of example. Yet further, wheels 70 may be used with the resistance block 20 and the track 12 for ease in moving the resistance along the track from position to alternate position, as illustrated with reference to FIG. 11.

For alternate embodiments of the invention, the coupling 38 may comprise a resistance modulator 72 for modifying a resistance felt by the resistance arm 34 at various locations within the second arc length 42 for a fixed preselected position of the resistance block 20 on the track 12, or at varying locations along the track for operations where the resistance block is moving as a result of the motor drive 56 continually or intermittently relocating the resistance block during a desirable exercise. By way of example, the resistance modulator may comprise a cam 74 (as illustrated with reference to FIGS. 12-14), a rod 76 (as illustrated with reference again to FIG. 1), a belt 78 (as illustrated with reference to FIG. 4), or a combination thereof. With continued reference to FIGS. 1, 6 and 8, the fixed link 13 may comprise a lift bar 80 fixedly attached to the track 12, wherein the lift bar includes opposing plates 82, 84 in spaced relation to each other or dimensioned for permitting the resistance block 20 to pass therebetween. The lift bar 80 may further include a link bar 86 providing an attachment point for a strap 88 forming a portion of the coupling 38. Alternatively, the fixed link 13, while fixed at a location on the track 12, may be pivotally attached to the track at a third axis 90, as illustrated with reference to FIG. 1A.

With reference again to FIGS. 12-14, an alternate embodiment of the invention may be described with reference to the apparatus 11, wherein a linkage 92 connects the movement arm 28 to the coupling 38. The linkage 92, for one embodiment herein described by way of example, may comprises a pulley assembly 94 rotatably connected to the frame 12 and a strap 96 connected between the pulley assembly and the movement arm 28 for operation of the coupling 38 through a movement of the movement arm. As illustrated by way of further example with continued reference to FIGS. 12-14, the movement arm 28 may be carried by a seat assembly 98. As illustrated with reference again to FIGS. 1 and 2, the movement arm 28 may further comprise adjustable means 100 for slidable movement of the resistance arm toward and away from the second axis 32 of rotation, thus allowing a modification to the length of the second moment arm 36. The adjustable means 100 may also include an adjustment to an angle of the movement arm 28, as may be desired.

As illustrated with reference again to FIGS. 1, 2, 12 and 13, the seat assembly 98 may comprise a base support 102 and a back support 104.

By way of further example, and with reference again to FIGS. 6-8, one embodiment of the apparatus 10 may include the track 12 constructed to have opposing side plates 12a, 12b connected at their respective ends by two end plates 12c, 12d. An outside plate 12e may be connected at an outside face of the end plate 12c. The threaded shaft 52 is positioned between the side plates 12a, 12b and may extend beyond the outside plate 12e, terminating at an extension 52a of the threaded shaft 52. As above described, the resistance block 20 may include a plurality of weight blocks 66 wherein a threaded nut 20a receives the threaded shaft 52. As illustrated with reference to FIGS. 10A and 11, the resistance block 20 may further include a plurality of axes 70a for rotatably securing the wheels 70 on opposite sides of the resistance block 20 adjacent the respective side plates 12a, 12b. One set of the wheels 70 is used for contacting opposite top surfaces of the side plates 12a, 12b, while another set of wheels is used for contacting opposite lower surfaces of the side plates. As above described, the resistance block 20 is thus supported for being fixed and rolled back and forth within the track 12 on the wheels 70. As illustrated with reference to FIG. 7, the resistance block 20 may optionally include a pair of side grooves 12f, 12g, along the length of their sides adjacent the side plates 12a, 12b for slidably receiving respective side guide rods 52b, 52c each extending from the opposing end plates 12c, 12d. The resistance block 20 may therefore be further supported and slide back and forth within the track 12 on the side guide rods 52b, 52c.

With reference again to FIG. 1, the first fulcrum 16 extends outward from either side plate 12a, 12b for securing the track 12 to a weight training machine such as the apparatus 10 and 11 herein described by way of example.

An attachment to the track may be a flexible tensile member such the strap 88 above described or may be a chain or rigid member to transmit a force to the movement arm 28. The threaded shaft 52 secures the resistance block 20 at the preselected position 26. To adjust the position of the resistance block 20 along the track 12, the threaded shaft 52 is rotated and the resistance block 20 is moved along the side plates to a desired location.

With reference again to FIGS. 1 and 2, and by way of continued example for one construction of the apparatus 10, to connect and secure the track 12, the first fulcrum 16 comprises bearings 16a. The fulcrum axis 18 is aligned and inserted into the bearings 16a carried by opposing frame bars 14a, 14b of the frame 14, thus securing the track 12 to the frame 14. The movement arm 28 of the apparatus 10, 11 (alternate weight training machines) may be coupled to an axle rotating about the axis 32.

The resistance modulator 72 may change the resistance so that the user is presented with enough resistance to be challenged but not enough resistive force to overcome to prevent completion of a desired exercise movement. The seated leg extension machine illustrated as the apparatus 10 may have a resistance profile that increases from the beginning of the exercise, progresses to a maximum when the knee joint forms an approximate 90 degree angle, and decreases to below the starting resistance at the end of the exercise. As above described and as illustrated by way of example with reference to FIGS. 12-14 for the apparatus 11, the track 12 and resistance block 24 structure herein described may be secured to any weight training machine capable of housing the track and resistance block while accommodating its rotation cycle and coupling the movement arm 28 or its equivalent to the track 12.

By way of example with regard to use or operation of the apparatus 10, 11, in selecting a desired level of resistance, a minimum level of resistance may be attained by positioning the resistance block 20 at the zero position, in which the center of mass of the track and resistance block generally coincides with the first fulcrum 16 (see FIG. 10 by way of example). At the zero position, the center of mass does not change height relative to the frame over the repetition cycle, and thus does not contribute any increase in potential energy to an increase in the level of resistance realized by the user. As will be clear to those skilled in the art, now having the benefit of the teachings of the present invention, a maximum level of resistance may be attained by positioning the resistance block at a maximum position, in which the center of mass is at the farthest position from the first fulcrum 16 (see FIG. 6 by way of example). At the maximum position, the center of mass experiences a maximum change in height over the repetition cycle, corresponding to a maximum increase in potential energy corresponding to a maximum increase in the level of resistance. As above described, the shaft 52 may be used to select a continuous level of resistance levels between the zero position and maximum position, through removably securing and positioning the resistance block 20 along the track 12. As illustrated with reference again to FIG. 1, a repetition cycle may have the track 12 move from being generally horizontal prior to the user imposing any force on the resistance arm 34 to a large angle as illustrated with reference again to FIG. 4.

By way of example with regard to a weight training program, the track carrying the resistance block accepts work from the user to rotate upward in a gravitational field, increasing the potential energy of the weight provided and thus the resistance provided to the user. On the return movement or eccentric portion of an exercise, the potential energy is returned to the user who expends work to lower the weight under control. Minimal frictional loss occurs during the movement of the track during a repetition cycle, as the weight only generates friction at the first fulcrum 16, which may be anti-friction ball bearings of appropriate size, for example. Such a weight resistance structure produces noticeably less friction than multiple plane bearings sliding along twin guide rods. Moreover, the leg extension machine of apparatus 10 illustrated in FIG. 1, for example, includes one resistance arm 34 interfaced with the movement arm 28 such that a desired resistance profile is achieved with only one idler pulley 38a in the connection from the movement arm 28 to the track 12. The relatively small number of drive train elements reduces frictional loss during the repetition cycle.

The torque that exercisers can transmit to an arm or pad of a machine varies with the movement of limb within the range of motion. The muscles that extend the leg at the knee (quadriceps) are able to produce 65% to 85% of the peak torque that occurs when the Tibia is approximately at right angles to the Femur. From this peak, the produced torque smoothly decreases to about 30% to 50% of the peak in the fully extended position. The resistance modulator 72 such as the cam and belt, cam and follower or linkage system as earlier described, may be such so as to provide a resistance to the user that matches the torque that the user can produce at a particular point in the range of motion. This means that the resistance provided by the apparatus 10, 11 is lower where the user produces less torque and is proportionally greater where the user is strongest. The torque that users can produce at various angles within the range of movement can be measured and averaged to come up with a machine resistance profile. These profiles vary for each muscle group and limb exercised as well as for the position of the users' body during the exercise. For instance, the torque and the range of motion of the hamstrings vary slightly when the hips and trunk are flexed or straight.

The resistance presented by a weight training machine must be less than the torque that the user can supply or the user will not be able to complete the repetition. In order to stimulate muscle growth however, the resistance should be challenging enough so that the body tends to rebuild. Ideally then, the resistance should be just slightly lower than the user's torque capacity at each angle in the range. This will ensure that the exercise can be completed through the full range of motion and the effort will be close to the maximum level that the user can apply at the strongest areas as well as the weaker angles.

One basis for designing a resistance modulation profile includes the law of conservation of energy. For weight training machines, the mechanical work input by the user equals the change in potential energy of the weight mass plus the friction plus kinetic energy. All other energy sources and sinks are neglected as inconsequential. In order for the resistance profile of the machine to be accurately presented to the user, the friction and kinetic energy component of the machine should be reduced to the greatest practical extent, as is the case from the embodiment of the invention herein described. The track and resistance block forming a resistance module based on a pivoting lever is inherently low in friction in comparison to weight stacks with guide rods, typically seen in the art. Keeping the distance traveled by the module center of mass less than the distance traveled by the engaging body part reduces the velocity of the resistance mass. The low velocity reduces kinetic energy content of the movement which is related by ½mv2. The m is mass and velocity is v. Because the friction and kinetic components of the repetition are reduced, the work added by the user more closely follows the resistance profile designed into the machine.

When the displacement of the center of mass of the resistance module over the repetition cycle is less than the resistance arm, by way of example, the velocity or acceleration is correspondingly less than that of the resistance pad and may not contribute large kinetic energy effects in addition to the inherent resistance profile. The resistance module may include the center of mass of the resistance module positioned along the side bars of the track such as at the maximum position, for example, and displacing a distance less than the resistance arm over the repetition cycle. Thus, for all resistance levels, the kinetic energy effects may be minimized. A less desirable configuration may include a small mass displacing a larger distance than the resistance arm, resulting in a higher travel velocity and high kinetic energy effects. The typical design for weight training systems have the distance traveled by the engagement pad or handle equal to or less than the distance traveled by the mass center of the resistance weight. The resistance module has the center of mass traveling less than the distance of the engagement handles and pads. Consider a distance traveled by the resistance arm or handles of an alternate apparatus, by way of example, to be Dh and the distance of travel of the weight module center of mass to be Dwt. The resistance module will follow the equation Dh/Dwt<1.

A repetition cycle may involve a concentric portion where the tension of the muscle and the direction of movement are the same, and an eccentric portion where the tension of the muscles and the direction of movement of the muscles are in opposite directions. During a biceps curl, for example, the concentric portion of the exercise may be lifting the weight and the eccentric portion may be lowering the weight.

The eccentric portion of a repetition in current weight training machines may involve less resistance due to frictional loss of the machines. However, the frictional loss of such machines may add to the resistance during the concentric portion of the repetition cycle. Thus, the frictional loss may add to the concentric resistance when lifting the weight and subtract from the eccentric resistance when lowering the weight. Thus, the eccentric portion of the repetition cycle may be less effective than the concentric portion.

The resistance module may provide a consistent level of resistance throughout the repetition cycle by supplying additional resistance during the eccentric portion to offset frictional loss. Increasing the resistance during the eccentric portion may be accomplished through moving the resistance block 20 away from the first fulcrum 16 when the user begins the lowering part of the exercise. By lengthening the distance the resistance block 20 can travel by 20%, for example, or decreasing the maximum concentric travel by 20%, for example, the muscles may encounter greater resistance in the eccentric portions of the repetition cycle. Upon the user beginning the concentric portion, the resistance block 20 may have returned to its initial position on the track 12.

The ability of the user to generate torque at a particular limb angle may be used to generate the resistance curve that is designed into the cam, lever or other resistance modulator 72 providing a modulating effect. The match between the programmed resistance curve and the user's ability to generate torque should be similar to accomplish an efficient exercise. If the match is not sufficiently similar, the user may not be able to exercise in a portion of the repetition range, nor be sufficiently challenged in a portion of the repetition range.

The resistance block 20, as above described, may be moved along the track 12 using the drive motor 56 controlled to adjust the position of the resistance block 20 to a particular position at the beginning of an exercise when a minimum amount of control is used. By increasing the amount of control, the motor may move the resistance block to the endpoints of the exercise to increase the eccentric phase of the exercise and decrease the concentric phase.

Consider a workout with increased eccentric phase resistance to include the following steps:

1. Set eccentric phase resistance level (may enter on a keypad 106 forming a portion of a controller 108, as illustrated with reference again to FIG. 1, by way of example)

2. Set concentric phase resistance level (enter on keypad)

3. Set range of motion (complete repetition with ½ concentric resistance, end points recorded)

4. Machine sets concentric value (moves weight block to position)

5. Machine signals ready to start (screen text, audio cue)

6. Start exercise

7. At the end of the range, pause under load for 2 seconds (weight moves to eccentric value)

8. Lower weight under control

9. Immediately begin to lift weight (weight moves to concentric value)

10. Repeat steps 6-9 (machine records repetition and time of exercise)

11. Exercise recording and weight changes stop when the range decreases to 80%

The eccentric and concentric resistance levels can also be set by entering either the concentric level or the eccentric level and entering the percentage increase of the eccentric over the concentric resistance levels. An increase of 2% to 5% would be equivalent to completely removing friction out of the exercise machine. In this case the addition of machine friction to the concentric movement and the subtraction of the machine friction from the eccentric movement would be offset exactly by the additional resistance for the eccentric movement. The eccentric strength level is commonly thought to be 40% greater than the concentric strength level. This could be the default setting for the machine when using the increased eccentric mode. Otherwise the percentage of increase would be entered by the user or trainer.

Consider a maximum effort workout to comprise the following steps:

1. Set range of motion with moderate speed full repetition (speed 3-8 second lift, 2-5 second pause-6-10 second lower and end points recorded)

2. Set concentric resistance to 1 RM or slightly lower (1 Repetition maximum or 5% to 10% lower)

3. Machine sets concentric value (moves weight block to position)

4. Machine signals ready to start (screen text, audio cue)

5. Start exercise

6. Machine records complete repetitions that are full range within 80%-90%.

7. Machine lowers weight until the range is within 80%-90% of the original

8. When concentric values are lower than the 1 RM by 20%40%, the increased eccentric resistance workout steps begin steps 8-9-10

9. When either concentric or eccentric phases are below 80%-90% of the range, the weight lowers until the range is restored.

10. Machine records full range repetitions and time of the exercise

11. Workout ends at selected repetition, time or percentage of starting weight.

An additional variation of a standard workout keeps the same resistance setting for the concentric and eccentric phases. This variation is similar to having a trainer or spotter assist the exerciser complete the last several repetitions.

A concentric workout with maximum effort finish may comprise:

1. Set concentric phase resistance level

2. Set range of motion

3. Machine sets concentric value (moves weight block to position)

4. Machine signals ready to start (screen text, audio cue)

5. Start exercise

6. Pause at the end of the range

7. Lower weight under control

8. Immediately begin to lift weight

9. Repeat steps 6-9 (machine records repetition and time of exercise)

10. When range of motion falls below 80%-90% of the recorder ROM, the weight reduces until the ROM is restored.

11. Reduction of weight continues for either a set number of additional repetitions or until the weight is a certain percentage of the original weight setting.

The increased eccentric phase workout can have the maximum effort finish as well. Consider the following.

1. Set eccentric phase resistance level

2. Set concentric phase resistance level

3. Set range of motion

4. Machine sets concentric value (moves weight block to position)

5. Machine signals ready to start (screen text, audio cue)

6. Start exercise

7. At the end of the range, pause under load for 2 seconds (weight moves to eccentric value)

8. Lower weight under control

9. Immediately begin to lift weight (weight moves to concentric value)

10. Repeat steps 6-9 (machine records repetition and time of exercise)

11. When either concentric or eccentric phases are below 80%-90% of the range, the weight lowers until the range is restored

12. Reduction of weight continues for either a set number of additional repetitions or until the weight is a certain percentage of the original weight setting

Yet further, the controller 108 may include a full servo feedback system may be used, for example, to control the position and velocity of the resistance block and enable the machine to superimpose a correction to the “hardwired” resistance curve that would enable an ideal match between the subject's ability and the machine's resistance. Such a hybrid electro-mechanical machine's primary resistance may be supplied by the resistance block being lifted and lowered while the servo-mechanics may shape the resistance to the user by making small change to the design in average resistance provided by the cam or levers. This system may differ from pure electronic exercise devices that use servo motors for resistance. The systems for electronic resistance machines may be very fast, accurate and generate great amounts of torque.

In an exemplary embodiment, a hybrid electro-mechanical system may only need the power and control to move a 100-400 pound mass along a low friction linear guide rod rather than having to generate up to 1000 to 1500 ft-lb of work in less than 90 degrees of movement arm rotation.

Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings and photos. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and alternate embodiments are intended to be included within the scope of the claims supported by this specification.