Duel purpose exercise device

Abstract
The disclosed invention is an exercise device being capable of providing aerobic exercise and abdominal muscle conditioning. The device is comprised of an upper frame and a lower frame. The upper frame includes a seat back which supports the upper portion of the torso of a user. The lower frame includes a pelvis support and a bicycle pedaling mechanism. The preferred embodiment includes a linkage system that connects the upper frame to the lower frame. This linkage is capable of providing a translating center of rotation when the upper frame rotates with respect to the lower frame. This is done to follow the body's translating center of rotation during trunk flexion. An alternative to the preferred embodiment includes a arcuate roller attached to the upper frame. This arcuate roller is preferably received by a track on the lower frame, and though preferable, the track is not necessary in order to achieve a translating center of rotation and therefore not necessary to the function of the invention. The upper frame and the lower frame are pivotally mounted one to another thus allowing the device to fold onto itself for easy storage.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The invention herein relates to a device for exercising the human body and more specifically to a combination abdominal exercise machine and a stationary exercise bike.




2. Overview of Prior Art




A variety of art exists in the area of exercise devices and inclusive of the areas of bikes for aerobic conditioning as well as abdominal exercisers. What has eluded the art thus far is a functional combination device that provides the capability to adequately perform in both realms of fitness.




The most apparent attempt was made by Shirley in U.S. Pat. No. 4,534,553 where a pedal and crank assembly drove an eccentric cam. The cam articulated with a plurality of bearings on the posterior of the seat back of the machine. Movement of the cam caused an angular displacement of the seat back and therefore some type of upper body flexion of the user. One of the problems with the device is the point of rotation (


14


in

FIG. 1

) of the seat back to the frame is located below the pad and the axis of rotation is a single pivot point.




The human body primarily undergoes trunk flexion by rotating the five lumbar vertebrae, each with respect to the adjacent vertebrae, including the fifth lumbar with the sacrum and the first lumbar with the twelfth thoracic vertebrae. This involves a translating center of rotation that runs aligned through the vertebral bodies, clearly above the seat. This misalignment would cause the user to slide on the seat back making it virtually non functional as a support for the user performing trunk flexion.




The second and most prevalent problem with the disclosure is that the cam causes the seat back to rotate up, which is driven by the pedaling motion. This means that the muscles of the user's legs are driving this movement, not the user's abdominal muscles. The movement may make the device somewhat enjoyable to use but it clearly does not function as an abdominal exerciser.




Another bike apparatus is disclosed by Zibell in U.S. Pat. No. 4,538,804 which includes an inclined slant board. Though the board could conceivably be used as a board for doing abdominal exercises, the board offers no support for the user during that movement. The disclosure specifies the purpose being to pull isometrically with the arms of the user while pedaling with the legs, not to function as an abdominal exerciser. The bench is also not disclosed to be able to be changed in angle, thereby disallowing the device to the used in a semi-recumbant position as an exercise bike, which would be most comfortable to most users.




An abdominal exercise device was disclosed by Abelbeck in U.S. Pat. No. 5,697,874 which includes a pad to place the pelvis of the user, creating a slight posterior rotation of the pelvis. The disclosure also specifies a mechanism that creates a translating center of rotation that is aligned with the vertebral rotation of the user's body during trunk flexion. The invention also includes a pad to support the head of the user, but the there is no device disclosed, nor anticipated to add an aerobic element of training to the device, specifically an exercise bike.




Another abdominal exercise device is disclosed in U.S. Pat. No. 4,729,562 by Pipasik. This disclosure relates only to a device that is intended to work the abdominal muscles of the user. The device uses two stationary pivots, one apparently near the lower chest of the user and the other near the hip. It is intended to stimulate the abdominal muscles by a flexion movement of a narrow region of the vertebral column and the hip. The latter would be primarily the hip flexor muscles, namely the Iliacus and the Psoas major, not the Rectus Abdominis.




Though the arcuate seat could place the user's pelvis in posterior rotation, it is the pelvis not the entire trunk that should be in constant slight flexion. The purpose of an abdominal exercise device is to cause the movement of trunk flexion. If, as here, the trunk is completely flexed before the exercise begins, there can be no flexion under load, because there is little if any flexion. The only realistic flexion could come from the hip, thus actuating the hip flexors, not the abdominal muscles. Therefore the disclosure would enable a device that is only marginally functional in terms of an abdominal exerciser and no suggestion to a combination with a device to provide aerobic exercise is made by the reference.




A unique device is disclosed by Mulenburg et al in U.S. Pat. No. 5,616,104 which includes a bike pedaling exercise apparatus. The disclosure includes the user being in a recumbent position but does not suggest to be used in any form of abdominal exercise. The device is intended to be used as a human centrifuge, the pedaling action causing the user to spin about an axis near the head of the user. The acceleration forces would be useful to counteract the effects of microgravity on persons exposed to an environment such as on prolonged space flights. As such, the addition of abdominal flexion would be of no value because the resistance to the user's muscles in this case is created by the effect of gravity on the body of the user. In a microgravity environment this is of little value.




A device is disclosed by Beistegui Chirapozu in U.S. Pat. No. 4,479,646 that incorporates a trunk vibration mechanism. The vibration mechanism is intended to provide a massage to the user during the exercise. The action of the vibrating mechanism is enabled as a result of the pedaling action of the exercise bike. It is unlikely that any benefit of massage is realized during exercise because the action of massaging a muscle enables it to relax while exercising a muscle causes it to contract. In any case, the vibrating mechanism that contacts the user's abdomen and lower back are adjustable to rigidly secure into place. Therefore the disclosed device does not suggest there be any form of abdominal flexion or other abdominal exercise be realized from the device.




A combination exercise bike is disclosed by Buchmann in U.S. Pat. No. 4,140,312 in that the pedal component can be adjusted into a variety of positions relative to the user. The user can sit in a variety of positions and actuate the pedals with the user's leg muscles. The device can also be oriented such that the user can actuate the pedals with the user's hands, thus exercising the muscles of the upper body. The combination does, in no way, disclose nor suggest functioning as an abdominal exercise device. There is a position that suggests two items (


13


and


14


in

FIG. 2

) could support the body of the user, but it is clearly not intended nor conceivably capable of allowing for trunk flexion with a user positioned thereon.




The disclosure of semi-recumbant exercise bikes is disclosed in U.S. Pat. Nos. D362,699 and 5,031,900 by Heaton et al, and Leask respectively. It is clear that both disclosures are relative to exercise bikes alone and not suggested to include any form of abdominal exercise device therewith.




SUMMARY OF THE INVENTION




The object of the disclosed invention is to provide a means of aerobic conditioning and abdominal muscle strengthening in one compact machine. Abdominal exercisers are commonly marketed as devices that reduce the user's body fat in the abdominal area. To adequately remove body fat an aerobic exercise is desirable, not just abdominal exercise. An aerobic exercise that uses large muscle groups, such as in the legs, is optimal. The disclosed invention uses a pedaling mechanism similar to that of a stationary exercise bike. The user is placed in a reclined position that is more comfortable, thus further facilitating the use of the invention. The device is further comprised of an abdominal exercise machine that provides a translating center of rotation to follow the actuation of the user's spine at it undergoes trunk flexion. This is done to provide for axial alignment of the machine to the user, thus providing continuous comfortable positioning of the user on the machine during use. When not in use, the device folds up for compact storage.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a side view of a user, shown in the supine position, identifying the critical centers of rotation of the human body during trunk flexion.





FIG. 2

is a side view of an exercise device shown with a user positioned thereon, the device being used in the fully recumbent or supine position as an exercise bike, the invention being produced in accordance with a preferred embodiment of the present invention.





FIG. 3

is a side view of an exercise device shown with a user positioned thereon, the device being used in a semi-recumbent position as an exercise bike and produced in accordance with a preferred embodiment of the present invention.





FIG. 4

is a side view of an exercise device shown with a user positioned thereon, the device being used as an abdominal exercise device, while also showing the user's foot position for adjusting the pedal position of the exercise bike, the device produced in accordance with a preferred embodiment of the present invention.





FIG. 5

is a cut away of a side view of the exercise bike portion of an exercise device produced in accordance with a preferred embodiment of the present invention.





FIG. 6

is a side view of an exercise device shown in a folded position for easy storage, the device produced in accordance with a preferred embodiment of the present invention.





FIG. 7

is a side view and a top view of an exercise device shown with the pedal position adjustment in the closest position, the device being produced in accordance with the preferred embodiment of the present invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




As technology becomes more advanced, we as a society become less physically active. As a result disease becomes more apparent as well as diminishing the quality of life on an every day level, in that daily activities become difficult due to the atrophy of the human body. To counteract this process physical activity must be a part of our lifestyles. For many, the availability of gyms and health clubs are not a viable option and so fitness equipment that is suitable for home use is the answer.




The accumulation of body fat has long been associated with disease (Manson, et al, 1991; Manson, et al, 1992 and Helmrich, et al). The benefits of exercise alone or in combination with a reduction in body fat is apparent in combating or preventing diseases (Wood, et al; Hyers, et al; Paffenbarger, et al; Helmrich, et al; Manson, et al, 1991; and Manson, et al, 1992). Abdominal products have filtered into the fitness market generating a notion of exercising the midsection would result in reducing the user's body fat in that area. This concept of “spot reduction” has no validity in the scientific community, but never the less “couch potatoes” open their wallets in the hope of creating a lean, ripped midsection with the investment of a few minutes a day.




Strengthening and developing the abdominal muscles does though have value to the user for a number of reasons. When the body fat is absent, a Herculean midsection is only possible if the abdominal muscles are developed. Additionally, the abdominal muscles help support the lumbar spine, a common sight of back pain. Incapacitating back pain will effect between 70 and 90% of Americans at some point in their lives (Margolis et al; 1997) at a cost of $100 billion annually (Margolis et al; 1998). Exercise has been shown to reduce the incidence of back pain (Bravo, et al; 1996). An optimal product would include abdominal exercise as well as cardiovascular conditioning, thus furthering the caloric expenditure of the exercise session, thereby reducing the body fat of the user.




Referring to the drawings,

FIG. 1

shows a side view of a body


10


in the supine position, as would be the case in one position of using the disclosed invention. The pelvis of the user has been manipulated to be put in slight posterior rotation, to be more advantageous in so far as reduced stress on the lumbar spine during trunk flexion. A series of circles are shown to depict the instantaneous centers of rotation of the vertebrae as the body


10


would undergo trunk flexion. The lowest, or anatomically inferior center


12


represents the center of rotation between the fifth lumbar vertebrae and the sacrum abbreviated L5-S1. The adjacent center


14


represents the center of rotation between the fourth and fifth lumbar vertebrae (L4-L5). The adjacent centers continue numerically to include the (L3-L4)


16


, the (L2-L3)


18


, and the (L1-L2)


20


. The lower Thoracic vertebrae can also contribute to trunk flexion. The respective centers are the (T12-L1)


22


and the (T11-T12)


24


. The proper aligmnent of the instantaneous center of rotation of the body to any machine that is used to guide trunk flexion is vitally important in that the machine must follow the natural movement of the user's body. If it does not, the machine is of little value.




The invention


26


is shown in

FIG. 2

with a user


10


in the supine position. Here it is being used as an exercise bike with the user's spine being fully unloaded during exercise. Such would be advantageous to persons rehabilitating lower back injuries where the stress of sitting would not be desirable or possible. This embodiment of the invention includes a seat back


28


to support the head, neck and upper back of the user, a handle


30


one each side of the user


10


. This combination comprises the upper frame of the invention


26


. A pelvis support


32


is shown under the pelvic region of the user


10


. Optimally it is produced as shown here with the posterior portion of the support being higher than the anterior portion. This arrangement places the user's pelvis in a slight posterior rotation.




A set of pivoting links


34


connect the upper frame, via the handle


30


to the pelvis support by way of the pivot plate


36


. A pedal mechanism


38


is shown here to be pivotally attached to a seat extension frame


40


. The pivotal attachment allows for the adjustment of the pedal position relative to the user. This is done to accommodate various body statures of individual users. The seat extension frame


40


is pivotally attached to the pelvis support


32


at pivot shaft


42


to provide a means of folding the invention


26


when it is not in use, thus enabling more convenient storage. This feature is shown in greater detail in FIG.


6


.




Another common use of the invention is shown in FIG.


3


. Here the seat back


28


is elevated by rotating the pivot plate


36


with respect to the seat frame bracket


44


and locking it in place by connecting one to the other with lower pin


46


. The seat back


28


is secured in place by fastening the pivoting links


34


one to another. One method is shown here by use of an upper pin


48


that passes through a hole placed in the pivoting links


34


. The result allows the user


10


to sit in a semi-recumbint position and exercise by use of the rotating the pedals of the pedal mechanism


38


. A novel use of the device which utilizes the pivoting links


34


in shown in FIG.


4


. Here the user is again positioned on the pelvis support


32


with the user's upper body against the seat back


28


. The pivot plate


36


is locked in the lower position, stationary to the pelvis support


32


and the links


34


provide for translation and rotation of the seat back


28


relative to the pelvis support


32


. The links


34


can allow this movement in a variety of ways, here it is due to the links


34


being comprised of a pair of pivoting links, an upper link


50


and a lower link


52


. In the down position, as is shown in

FIG. 2

, the upper link


50


is pivotally fastened to the handle


30


above the lower link


52


. At the base of the seat the upper link


50


is pivotally fastened below the lower link


52


. This cross over provides a translation of the center of rotation of the seat back


28


and the user's upper body supported thereon when the seat back


28


is rotated The positioning of the links as shown provides a translating center of rotation which follows the path of the center of rotation of the body (items


12


-


24


in FIG.


1


).




Similar results could be achieved through use of a rolling device such as an annular rail which would be fixed to the seat back


28


on the upper frame by use of the handle


30


with the annular rail being received in a track which would be secured to the pelvis support


32


. Though such a device would function well, the bulky nature of such a design and the necessity of controlling the movement of the annular rail in the track would provide additional complications that the disclosed linkage mechanism does not have.




Also shown in

FIG. 4

is the use of the pedal adjustment


54


. The user's foot


56


is placed on the adjustment pedal


58


. By pushing thereon, the user


10


will cause the notched ring


60


to rotate about the axis pin


62


. This allows the notches


64


to disengage from the rod


66


, freeing the pedal mechanism


38


to rotate about the pivot mount


68


, thus varying the distance of the pedals


70


to the user


10


. The device also includes a tension spring


72


to keep any given notch


64


engaged with the rod


66


when the device is in use. When the device is being used as an abdominal exercise device, as shown here, the user


10


can place their feet under the rod


66


to aid in holding the user's position in the device. This is illustrated by the user's left foot


74


.




A preferred embodiment of the pedal mechanism


38


is shown in greater detail in FIG.


5


. The enclosure


76


is cut away to show the pedal drive mechanism. This includes a pair of pedals


70


which are rotateably mounted to a crank arm


78


, the crank arm


78


being journaled to a framework


80


by a bearing


82


. A drive sprocket


84


is mounted to the crank arm


78


which mechanically communicates with the flywheel sprocket


86


by use of the chain


88


. The flywheel sprocket


86


is connected to the flywheel


90


which is journaled to the framework


80


by clutch bearing


92


. The clutch bearing


92


provides rotation of the flywheel


90


when the pedals


70


are driven clockwise, as depicted by the arrow


94


and allows the flywheel to spin freely when the pedals


70


are not moving. Resistance to the drive mechanism is applied by contact between the belt


96


and the flywheel


90


. The tension is controlled by varying the tension in the belt


96


by rotating the screw knob


98


.




This drive mechanism is not unusual from many exercise bikes and it is not considered necessary to the novelty of the disclosed invention. The use of chains and sprockets to drive a flywheel, and even the existance of the flywheel is desireable, but not critical to the invention. The chain


88


can be replaced with a belt and the flywheel with an electromagnetic resistance device such as an eddy current brake or an alternator. A second reduction in the transmission of rotary power can also be made if higher rotational velocity is desired by the resistance device. The given disclosure is considered to be the most efficient method as per the marketability of the device as dictated by price and function.




Another novelty to the disclosed invention is depicted in

FIG. 6

in which the device folds onto itself to reduce the storage size. This is possible by a lower frame of the device which is comprised of two parts, a first frame portion


100


and a second frame portion


102


. The first frame


100


supports the pedal mechanism


38


. The first frame portion


100


is pivotally connected to the second frame portion


102


at the pivot mount


68


which also supports the pedal adjustment


54


. The second frame portion


102


is pivotally connected to the pelvis support


32


with the pivot shaft


42


. The lower frame is able to be folded onto the seat back


28


by pivoting the device at the pivot shaft


42


.




Top and side views of the invention are shown in FIG.


7


. The basic function of the device is consistent with that already disclosed. The pedal mechanism


38


is shown to be adjusted in the closest position to the user. The second frame portion


102


is pivotally mounted to the pelvis support


32


. This is done to allow for adjustment in position of the pedal mechanism


38


between use and storage, similar to previously disclosed, only here an adjustment lock


104


has been added. The lock


104


provides two positions, one for use, as shown here in which the locking pin


106


is positioned in the lower lock bole


108


. The locking pin


106


moves with the second fame portion


102


. This enables the device to be locked in position for storage by rotating the locking pin


106


and second frame portion


102


toward the seat back


28


and securing the locking pin


106


in the upper lock hole


110


. This provides easy and secure storage of the device. The seat back


28


can likewise be secured from moving with respect to the pelvis support


32


by securing pins


112


through link hole


114


. As previously stated, this is also used to secure the seat back


28


into a set position, as shown in

FIG. 3

, when the device is used as a semi-recumbent exercise bike.




What is disclosed is considered to be a preferred embodiment. Variations to the disclosed invention are infinite without changing the function and unique combination of the exercise bike and abdominal exercise device.



Claims
  • 1. An exercise device comprising:a lower frame; a pair of pedals, each of the pedals connected to a crank arm, the crank arms connected by a shaft that is journaled to said lower frame, thus enabling rotary motion of the pedals; an upper frame including a seat back capable of supporting a portion of the torso of a user lying in a supine position thereon, the upper frame including at least one handle; and a device for providing a consistent translating center of rotation, the device connecting said upper frame to said lower frame.
  • 2. The exercise device as described in claim 1, further comprising a flywheel rotatably mounted to said lower frame and in communication with said pair of pedals, whereby the actuation of said pair of pedals enables rotational movement of the flywheel.
  • 3. The exercise device as described in claim 1, further comprising a resistance device adapted to communicate with said pair of pedals thereby offering resistance in the movement thereof.
  • 4. The exercise device as described in claim 3, wherein said resistance device is adjustable.
  • 5. The exercise device as described in claim 1, wherein said device for providing a consistent translating center of rotation further comprises:an upper link and a lower link, both links including a first end pivotally mounted to said upper frame, the upper link mounted above the lower link, and both links having a second end pivotally mounted to said lower frame, the upper link mounted below the lower link thereon.
  • 6. The exercise device as described in claim 1, wherein said device for providing a consistent translating center of rotation is comprised of an arcuate roller portion that is attached to said upper frame, the roller portion articulating with said lower frame, thereby creating a translating center of rotation.
  • 7. The exercise device as described in claim 1, wherein said lower frame includes a pelvis support.
  • 8. The exercise device as described in claim 7, wherein said pelvis support is comprised of a pad that has a varied thickness with a thicker portion positioned toward said pair of pedals and the thinner portion toward the upper frame, whereby when the user's pelvis is situated thereon the inferior portion of the pelvis is higher than the superior portion, thus putting the user's pelvis in posterior rotation.
  • 9. The exercise device as described in claim 7, wherein said lower frame is comprised of a first frame portion and a second frame portion, the first frame portion being pivotally connected to the second frame portion with the first frame portion receives said shaft that connects said crank arms and the second frame portion is pivotally connected to said pelvis support, thus enabling the lower frame to fold to reduce the size for storage.
  • 10. The exercise device as described in claim 9, wherein said lower frame is further comprised of a variable locking means to alter and releasably secure the position of said first frame portion to said second frame portion, whereby the position of the pedals can be adjusted according to the needs of the user.
  • 11. An exercise device comprising:a lower frame; a pair of pedals, each of the pedals connected to a crank arm, the crank arms connected by a shaft that is journaled to said lower frame, thus enabling rotary motion of the pedals; an upper frame, including a seat back capable of supporting a portion of the torso of a user lying in a supine position thereon, the upper frame including at least one handle; and a device for providing both a consistent translating center of rotation and a single axis rotation, the device connecting said upper frame to said lower frame.
  • 12. The exercise device as described in claim 11, further comprising a flywheel rotatably mounted to said lower frame and in communication with said pair of pedals, whereby the actuation of said pair of pedals enables rotational movement of the flywheel.
  • 13. The exercise device as described in claim 11, further comprising a resistance device adapted to communicate with said pair of pedals thereby offering resistance in the movement thereof.
  • 14. The exercise device as described in claim 13, wherein said resistance device is adjustable.
  • 15. The exercise device as described in claim 11, wherein said device for providing both a consistent translating center of rotation and a single axis rotation is comprised of:an upper link and a lower link, both links including a first end pivotally mounted to said upper frame, the upper link mounted above the lower link, and both links having a second end pivotally mounted to a pivot plate, the upper link mounted below the lower link thereon and the pivot plate being pivotally mounted to said lower frame.
  • 16. The exercise device as described in claim 11, wherein said device for providing a consistent translating center of rotation is comprised of an arcuate roller portion that is attached to said upper frame, the roller portion articulating with a guide that is pivotally attached to said lower frame, thereby creating a translating center of rotation when the guide is stationary to said lower frame and allowing rotation of the upper frame about a single axis when the roller portion is stationary with respect to the guide and the guide rotates with respect to said lower frame.
  • 17. The exercise device as described in claim 11, wherein said lower frame includes a pelvis support.
  • 18. The exercise device as described in claim 17, wherein said pelvis support is comprised of a pad that has a varied thickness with a thicker portion positioned toward said pair of pedals and the thinner portion toward the upper frame, whereby when the user's pelvis is situated thereon the inferior portion of the pelvis is higher than the superior portion, thus putting the user's pelvis in posterior rotation.
  • 19. The exercise device as described in claim 17, wherein said lower frame is comprised of a first frame portion and a second frame portion, the first frame portion being pivotally connected to the second frame portion with the first frame portion receives said shaft that connects said crank arms and the second frame portion is pivotally connected to said pelvis support, thus enabling the lower frame to fold to reduce the size for storage.
  • 20. The exercise device as described in claim 19, wherein said lower frame is further comprised of a variable locking means to alter and releasably secure the position of said first frame portion to said second frame portion, whereby the position of the pedals can be adjusted according to the needs of the user.
  • 21. A method of physical exercise for a user including the steps of:providing a device including a lower frame; a pair of pedals, each of the pedals connected to a crank arm, the crank arms connected by a shaft that is journaled to said lower frame, thus enabling rotary motion of the pedals; an upper frame including a seat back capable of supporting a portion of the torso of said user when position thereon, the upper frame including at least one handle; and a device for providing a consistent translating center of rotation, the device connecting said upper frame to said lower frame; positioning said user on said exercise device in a supine position with the feet of said user on said pedals; and rotating said pedals about said shaft by applying force to said pedals by said user.
US Referenced Citations (13)
Number Name Date Kind
D. 362699 Heaton et al. Sep 1995
4140312 Buchmann Feb 1979
4479646 Chirapozu Oct 1984
4534553 Shirley Aug 1985
4538804 Zibell Sep 1985
4729562 Pipasik Mar 1988
4974840 Welch Dec 1990
5031900 Leask Jul 1991
5178589 Wilson et al. Jan 1993
5254067 Habling et al. Oct 1993
5616104 Mulenburg et al. Apr 1997
5697874 Abelbeck Dec 1997
5833582 Chen Nov 1998
Non-Patent Literature Citations (9)
Entry
Hyers, T.M., et al (1980) Enhansed Trrombin and plasma activity with exercise in men, J. Appl. Physiol., 48 (5): 821-825.
Paffenbarger, R.S. Jr., et al (1984) A natural history of athleticism and cardiovascular health, JAMA, 252 (4): 491-495.
Manson, J.E., et al (1991) Physical activity and incidence of non-insulin-dependent diabetes mellitus in women, Lancet, 338: 774-778.
Manson, J.E., et al (1992) A prospective study of exercise and incidence of diabetes among U.S. male physicians, JAMA, 268 (1): 63-67.
Helmrich, S.P., et al, (1991) Physical activity and reduced occurance of non-insulin-dependent diabetes mellitus, N Engl J Med, 325: 147-152.
Wood, P.D., et al. (1976) The distribution of plasma lipoproteins in middle-aged male runners, Metabolism, 25 (11): 1249-1257.
Margolis, S. and Kostuik, J.J., (1997) John Hopkins White Papers 1997, Medletter Associates, Inc, New York, p 4.
Margolis, S. and Kostuik, J.J., (1998) John Hopkins White Papers 1998, Medletter Associates, Inc. New York, p 4.
Bravo, G., et al. (1996) Impact of a 12-month exercise program on the physical and psychological health of osteopenic women, J Am Ger Soc, 44: 756-762.