Unassisted lower torso strengthening and stretching device

A device for stretching and strengthening the muscles of the lower back and legs of a person in a supine position. The device includes a board with straps to restrain the pelvis of the person. A rope and pulley system, operated by the person by pulling and releasing extends between the feet and to a support above the head. The rope is pulled by the user to raise the legs, and additional mechanical advantage is employed as the rope is gradually released to lower the legs.

BACKGROUND OF THE INVENTION 
This invention related to a method and apparatus for stretching, exercising 
and strengthening the muscles of the lower back and legs, and more 
particularly, to a method and portable apparatus which may be used and 
employed unattended by a single user. 
A method for stretching hamstring and lower back muscles and strengthening 
such muscles is described in The Goodbye Back Pain Handbook by James A. 
Peterson et al (Masters Press, 5025 28th St., S.E., Grand Rapids, MI 
49506). The authors describe lessened back pain and improved flexibility 
in hundreds of patients during a two year period. In general, the patient 
lies on a padded board and is restrained around the waist with a strap to 
stabilize the pelvis. A second person then places one foot on the board 
and lifts the patient's legs by the ankles upwardly toward the head in a 
repetitive manner to stretch the lower back and hamstring muscles. The 
same muscles are strengthened by having the assistant provide controlled 
resistance to downward movement of the legs. 
While the above exercises and method have been proven effective, the method 
requires the use of an assistant or so-called training partner, preferably 
who has experience or training with the system. The requirement of an 
assistant limits the practical usage and availability of the method. The 
assistant must be available to lift the legs to about a 90 degree 
position, and then push the legs toward the head to stretch the muscles. 
Also, the assistant must hold the ankles and support the legs during 
downward movement. Different forces are required to execute these two 
separate phases, and the forces may vary, depending on the condition of 
the patient. 
SUMMARY OF THE INVENTION 
The apparatus present invention comprises two components, namely, a pelvis 
stabilizing means comprising a support board with a pelvis restraining 
strap, with the board being designed to prevent lifting of the board from 
the floor or support surface while being used. The second component is a 
rope and pulley system connected between the feet or ankles of the user 
and a support above the head of the user. The pulley and rope system 
terminates in a free end of the rope above the arms of the user, which 
allows the user to pull the legs upwardly toward the head, and to 
gradually lower the legs toward the floor. 
The pulley and rope system is designed to provide a first mechanical 
advantage as the rope is pulled to lift the legs, and a second, greater, 
mechanical advantage when the legs are being lowered by gradual release of 
the rope. The system may comprise a pair of free pulleys to provide a two 
to one advantage in the upward or pulling direction. One of the pulleys 
may be in the form of a rope clutch or reverse friction device to resist 
movement in the other direction, i.e., when the legs are being pushed 
toward the floor. This allows a greater than two to one mechanical 
advantage in the other direction and lessens or eliminates the problem of 
undue stress or slippage of the rope through the hands of the user.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The two essential components of the present invention are shown in FIGS. 
1-3. The first component comprises a means to restrain and immobilize the 
pelvis of the user in a fixed position relative to the other portions of 
the apparatus. The second component comprises a rope and pulley system 
extending between the ankles and to a position above the head of the user, 
said system being operable by the hands and arms of the user by pulling on 
and releasing the rope. The rope and pulley system includes means to 
provide greater mechanical leverage in the release direction than in the 
pulling direction. 
The first component may comprise a flat rigid board 10 having planar 
dimensions to accommodate torso sizes of various users. The board may 
include means such as the indicated slots 12 near one end of the board 
adjacent the longitudinal edges thereof for securement of adjustable 
straps 14 which encircle the waist of the user and hold the pelvis against 
the board, while allowing the legs to swing upwardly. The board may 
include an additional slot 16 at the center near one edge to provide a 
hand hold to facilitate movement of the board from one location to 
another. 
The purpose of the board 10 is to stably position and restrain the pelvis 
of the user relative to the location of the pulley system to be described 
herein. The board 10 is supported upon a horizontal surface and has a 
length which is greater than the upper torso and head of the user as 
shown. From experimentation, it has been found that a length between the 
slots 12 to the other or remote edge 18 of the board should be in the 
order of 40 to 44 inches. The edge 18 of the board abuts a vertical 
surface, such, as a wall 20, to prevent the board from moving lengthwise. 
Preferably, there is a length of board between the head of the user and 
the supported edge of the board 18, such that the body weight of the user 
will be enough greater than the lifting force of the pelvis strap 14 that 
the board will not significantly lift or fulcrum around the edge when in 
use. 
The use of a separate board 10 having the pelvis support near one end and 
an abutting edge 18 at the other end enables the apparatus to be portable 
and easily moved from one location to another. Obviously, the pelvic 
support could be in a permanent location, or the board could be otherwise 
secured to its supporting surfaces. 
The second component comprises a mechanical system to enable the user to 
lift or rotate one or more legs from the ankles or feet in the supine 
position upwardly and generally toward and away from the head in a 
controlled fashion. In the preferred embodiment, the mechanical system is 
a pulley and rope system connected between the ankle area of the user and 
a support above the head of the user. The rope may be pulled and released 
by the user in a lightly controlled fashion to raise and lower the legs as 
hereinafter described. 
As shown in FIGS. 1 and 2, the system preferably comprises a rope 30 having 
one end connected to a first pulley 32, extending around a second pulley 
34 and then around the first pulley to a free end operable by the hands of 
the user. Means, such as boots 36, straps, or other supports, extend 
around the feet or ankles of the user, and a line 38 is connected between 
the boots 36 and to the sides or non-rotating portion of the second pulley 
34. 
The first pulley 32 is provided with a head which is connected by a line 40 
to a support generally above and to the rear of the head of the supine 
user, as shown. The support may comprise a terminus such as a disc 42 
located on the other side of a closed door in the well known fashion, as 
shown. The door is opened, and the disc 42 is placed on th other side 
before the door is closed, with the flexible line 40 extending between a 
crack between the door edge and the frame. 
As shown in FIG. 1, the line 40 is preferably supported at a height such 
that the pulley system is substantially horizontal when the legs are 
raised to a 90 degree angle as shown. This may be accomplished by 
supporting the line 40 at approximately the height of the navel of the 
user from the ground. 
The pulleys 32 and 34 provide what is a two part system in which the pulley 
34 moves toward and away from the relatively fixed pulley 32 as the rope 
30 is pulled in and released by the user. Both pulleys are designed to 
turn freely as the free end of the rope 30 is pulled by the user, 
providing a two to one mechanical advantage to facilitate the lifting and 
stretching movement. 
The relatively movable pulley 34 is designed to provide resistance to the 
passage of the rope when the rope is released gradually by the user. Such 
pulley may include a ratchet mechanism and a special pulley sheave to 
provide additional resistance and mechanical advantage in the release 
direction. 
Various types of one way rope clutches may be employed to achieve the 
described function of pulley-clutch 32. One particularly suitable type is 
sold under the trademark "HEXARATCHET" by Harken, Inc. of Pewaukee, Wisc., 
U.S.A. The bearing block is described in more detail in Gilson U.S. Pat. 
No. 3,714,838, incorporated herein by reference to FIGS. 4 and 5. 
As shown in FIGS. 4 and 5, the pulley-clutch 32 comprises a grooved, 
rope-receiving sheave 50 which is disposed between side plates 52 and 
rotates around an axis on bearings 54. The sheave 50 may have inwardly 
projecting teeth 56 which are engageable by a spring loaded pawl 59 in one 
direction of rotation. In the other direction of rotation, the pawl 59 
slides over the teeth 56. Thus, the sheave 50 can rotate in only one 
direction. 
As shown in FIG. 5, the rope receiving groove 60 of the sheave 50 may have 
an irregular surface such as v-shaped shoulders 62 on the sides of the 
grooves and chordal segments 64 at the bottom of the groove. This 
increases sliding friction between the rope and stationary sheave to 
obtain a frictional mechanical advantage in the order of about from five 
to fifteen to one, depending on the tension of the rope. Generally, the 
mechanical advantage or friction increases in proportion to the tension on 
the rope, as more fully described in the aforesaid U.S. patent. 
The use of the apparatus of the present invention will now become apparent. 
Once the apparatus has been assembled as shown in FIG. 1, the user pulls 
on the rope 30 with the legs unbent until the legs are in an upright 
position, or approximately 90 degrees to the 
board 10. The pulley arrangement shown is a 2 to 1 system, by which two 
unit lengths of rope are pulled downwardly to provide one unit length of 
upper lift. This facilitates lifting the legs to an upright position with 
the use of the hands and arms alone. 
With the legs in the upright position, two different types of exercise are 
possible. Additional pulling on the rope to a controlled and limited 
degree causes the feet and ankles to move toward the head to stretch the 
muscles in the lower extremities. 
A second type of exercise is one in which the user provides muscle power to 
push the feet from an upright position toward the floor in a gradual 
manner while allowing slippage of the free end of the rope. Since the 
large muscles in the lower body together with gravity can produce a large 
downward force, a corresponding resistance is generated by the pulley 
system, especially at the ratchet block. Otherwise, the large forces might 
cause the rope to slip through the hands of the user, with resulting rope 
burns or muscle strain or injury.