Patent application title: Exercise pole
R. Bruce Kezer (Knoxville, TN, US)
IPC8 Class: AA63B2102FI
Class name: Exercise devices user manipulated force resisting apparatus, component thereof, or accessory therefor utilizing resilient force resistance
Publication date: 2012-12-20
Patent application number: 20120322632
An exercise pole comprises a flexible stick having a hand grip at one end
and a ground-engaging tip at the other end. The stick is made of any
suitable material in any suitable length, and the material and diameter
are selected so that the stick may be bent elastically to a significant
degree by the user applying a load or bending moment to the hand grip.
The poles are preferably used in pairs, one in each hand. Walking with
the inventive poles in hand, the user plants one pole on the ground and
flexes it; the bending moment applied to flex the stick is resisted by
tightening of the abdominal muscles. The user may plant the sticks ahead
of or alongside the feet, flex the sticks, and then allow them to unflex
in a controlled way while maintaining some tension. The poles can also be
used indoors and while seated.
1. An exercise pole comprising: a flexible shaft capable of repetitive
elastic flexure of at least 2% of its length in response to a bending
load; a hand grip on the upper end of said flexible shaft to allow a user
to apply said bending load; and, a ground-engaging tip on the lower end
of said flexible shaft to engage a selected working surface.
2. The exercise pole of claim 1 wherein said flexible shaft is between about 75 cm and 2 m long.
3. The exercise pole of claim 1 wherein said flexible shaft comprises a material selected from the group consisting of: wood, metal alloys, polymers and polymer composites
4. The exercise pole of claim 3 wherein said flexible shaft comprises a solid fiberglass reinforced polymer rod.
5. The exercise pole of claim 1 wherein said hand grip comprises a compliant sleeve.
6. The exercise pole of claim 1 wherein said hand grip has indentations to accommodate the fingers of the user.
7. The exercise pole of claim 1 wherein said hand grip is co-linear with the axis of said flexible shaft.
8. The exercise pole of claim 1 wherein said hand grip is offset at a selected angle from the axis of said flexible shaft.
9. The exercise pole of claim 1 wherein said ground-engaging tip comprises a compliant molded rubber cane tip.
10. The exercise pole of claim 1 wherein said ground-engaging tip comprises a hard point.
11. A method of exercise comprising the steps of: grasping a flexible shaft, using a hand grip at the upper end of said shaft, said shaft further having a ground-engaging tip at its lower end; placing said tip on a working surface; applying a bending moment through said hand grip sufficient to deflect said flexible shaft at its midsection by at least about 2% of its length; reducing said bending moment so that said flexible shaft returns controllably to a straight position before lifting said tip from said working surface.
12. The method of claim 11 wherein two of said flexible shafts are used, one in each hand.
13. The method of claim 11 wherein said steps are performed while walking.
14. The method of claim 11 wherein said steps are performed while seated.
15. The method of claim 11 said steps are performed indoors and said working surface comprises an interior surface of a room.
BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The invention pertains to exercise equipment and methods of using the same. More particularly the invention relates to a flexible pole for upper body exercises, particularly when walking.
 2. Description of Related Art
 It is known in the art of exercise physiology that one can greatly increase the effectiveness of walking by doing various movements to involve the muscles of the upper body. This can be done by the use of wrist weights, for example, or by carrying various poles, sticks, and the like. In some cases, hiking sticks or poles are modeled after ski poles and this practice is commonly referred to as Nordic walking. The poles are generally substantially rigid and are used by grasping the upper end and pushing the lower end backwards against the ground, thereby propelling the user forward and exercising the arm muscles.
 Some typical walking poles are disclosed by: Helm in U.S. Pat. Appl. Pub. 2009/0314320; Stephens et al. in U.S. Pat. Appl. Pub. 2008/0121260; and Dale in U.S. Pat. No. 4,958,650.
 Ski poles are made of various materials, such as aluminum and composite materials, as taught by Goode in U.S. Pat. No. 5,024,866. As Goode makes clear, a ski pole must be strong enough to adequately support the body weight of a skier, and must withstand significant bending loads without bending too much.
 Reilly, in U.S. Pat. Appl. Pub. 2010/0179037, discloses an exercise pole intended to be used primarily for stretching exercises. The pole is substantially rigid along most of its length and has a partially flexible handle, intended to relieve stress on the hands and the wrists of the user.
 Wright, in U.S. Pat. No. 5,739,139 discloses a set of lunge poles, which are rotatably mounted in a base. The poles are substantially rigid and serve to help the user maintain his or her balance while performing lunging exercises. The poles may be joined together by a resilient band in order to increase the resistance to relative movement in order to increase the intensity of the workout.
 The aforementioned devices suffer from various shortcomings that limit their usefulness in several exercise regimes. First, conventional Nordic walking poles don't provide adequate involvement of the abdominal muscles, because the user is simply pushing backwards against the ground. Second, all of the poles are substantially rigid and therefore don't provide an element of resistance over a wide range of motions. Third, they tend to be limited to either walking or stationary exercises and are not adapted to both.
OBJECTS AND ADVANTAGES
 Objects of the present invention include the following: providing an exercise pole that can be used in both walking and stationary exercise activities; providing a flexible exercise pole that may be elastically deformed over a wide range to provide resistance over a range of muscle movement; providing a walking pole that allows the user to apply a controlled bending moment that is resisted by the user's abdominal muscles; providing an exercise pole that may be used in both walking and stationary settings; providing an exercise pole that may be used in both indoor and outdoor activities; and providing a method of exercise in which walking poles are flexibly bent and unbent to provide additional muscle involvement for the user. These and other objects and advantages of the invention will become apparent from consideration of the following specification, read in conjunction with the drawings.
SUMMARY OF THE INVENTION
 According to one aspect of the invention, an exercise pole comprises:
 a flexible shaft capable of repetitive elastic flexure of at least 2% of its length in response to a bending load;
 a hand grip on the upper end of the shaft to allow a user to apply the bending load; and,
 a ground-engaging tip on the lower end of the shaft to engage a selected working surface.
 According to another aspect of the invention, a method of exercise comprises the steps of:
 grasping a flexible shaft, using a hand grip at the upper end of the shaft, the shaft further having a ground-engaging tip at its lower end;
 placing the tip on a working surface;
 applying a bending moment through the hand grip sufficient to deflect the flexible shaft at its midsection by at least about 2% of its length;
 reducing the bending moment so that the flexible shaft returns controllably to a straight position before lifting the tip from the surface.
BRIEF DESCRIPTION OF THE DRAWINGS
 The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting embodiments illustrated in the drawing figures, wherein like numerals (if they occur in more than one view) designate the same elements. The features in the drawings are not necessarily drawn to scale.
 FIG. 1 is a schematic diagram of one embodiment of the present invention.
 FIG. 2 is a schematic diagram of the invention being used as a conventional walking stick.
 FIG. 3 is a schematic diagram of the invention being gripped on the upper part of the handgrip to encourage flexure of the stick
 FIG. 4 is a schematic diagram of the applied and reactive moments generated during flexing of the inventive exercise pole.
DETAILED DESCRIPTION OF THE INVENTION
 In its most general form, FIG. 1, the invention comprises a flexible stick having a hand grip at one end and a ground-engaging tip at the other end. The stick is made of any suitable material in any suitable length, and the material and diameter are selected so that the stick may be bent elastically to a significant degree by the user applying a load or bending moment to the hand grip. The sticks are preferably used as a pair, one in each hand. Further details of some exemplary designs, and details of several methods of using the invention to improve exercise activities, will be presented in the following examples, which are for illustrative purposes and are not intended to limit the scope of the invention.
 Conventional ski poles and Nordic walking sticks are substantially rigid bodies. They may exhibit a small degree of flex or compliance, but they are not intended to be repetitively flexed by the user in order to work various muscle groups. A Nordic walking stick is used by engaging the lower tip on the ground and pushing backwards, thereby propelling the body forward, in the same way that one would use the poles in Nordic or cross-country skiing. From a kinematic viewpoint, the arms are simply providing some of the work needed to move the user forward, rather than all of the work being provided by the leg muscles. Because conventional poles have no significant degree of elastic flexure, they can't provide the user with a resistive workout over a large rotational movement.
 By contrast, the inventive poles are extremely flexible. The user engages the lower tip on the ground and applies a bending moment with the wrist. As shown in FIG. 4, the reactive moment is transferred to the user's upper body and resisted by the user's abdominal and other related muscles. It will be appreciated that the user may, in some circumstances, simply press downward with adequate force to cause the stick to buckle elastically; however, Applicant has found that twisting the wrists to apply a bending moment is more natural and more easily controlled than inducing buckling. In following through, the user continues to apply a resisting force to the stick as it straightens, rather than simply allowing it to spring back uncontrollably. In this way, the user thereby gains the benefit of muscular exertion over a wide range of movement, providing improved efficiency of the exercise activity.
 The stick 10 shown in FIG. 1 may be made of any suitable material whose length, diameter, and modulus of elasticity provide a reasonable degree of flexure. It will be understood that for a given material, the optimal diameter will be related to the overall length; i.e., a longer stick would flex more under a given load than would a shorter one of the same diameter. It will be further understood that different users will require sticks of different lengths, with taller users generally preferring longer sticks. Most users will prefer a stick that is at least 1 m long, and preferably between 1 and 2 m long; however, for specialized applications as described in later examples, a somewhat shorter stick may be used. Thus, through routine engineering, for a given stick length, the material and diameter can be chosen to provide a stick with the appropriate amount of flex, which will be described in more detail in further examples.
 One material that Applicant has found to be suitable for the stick is a solid polymeric (fiberglass reinforced) shaft about 9 mm diameter (Vinylester Rod 3/8'' diameter, black, Glasforms, Inc., Birmingham, Ala. 35217). With this material, a stick about 1.3 m long can easily be flexed by about 10 cm (measured as the deflection of the center of the stick from the line joining the two ends). Selected specifications for this material are: Glass Content, 75 wt. %; Tensile Strength, 120,000 psi; Tensile Modulus, 6×108 psi; Flexural Strength, 120,000 psi; Flexural Modulus, 6×106 psi; Compressive Strength, 6,000 psi; Barcol Hardness, 60 (ASTM D2583).
 Applicant has found that this material is quite resilient and has shown no signs of fatigue or other incipient mechanical failure after repeated flexure.
 It will be appreciated that other familiar materials such as wood, metal alloys, polymers and polymer composites may also be used, provided their diameter and length are matched so that adequate flexure can be induced with appropriate force by the user, and the stick will at all times deform in the elastic (rather than plastic) regime.
 The stick in the preceding example was fitted with a compliant tip 11 on the end that is intended to engage the ground or other surface. One suitable tip is a standard rubber product (Chair, Cane, and Crutch Tips, black, 3/8 inch ID, McMaster-Carr, Atlanta, Ga. 30036). Other suitable materials may be used, which preferably meet the following criteria: 1. The diameter of the tip is larger than the diameter of the stick so it may be slipped onto the stick; and 2. The tip material is appropriate for the intended working surface.
 For outdoor use, the tip may be fitted with a relatively hard point, whereas for indoor use the tip is preferably softer than the stick material, as was used in the preceding example. These qualities allow the tip to engage an irregular working surface securely, and also help to prevent damage to surfaces when used indoors, or damage to the stick when used on pavement or rocky terrain as will be explained in later examples. The hard point intended for outdoor use may be of any suitable material including hardened steel, metal carbides, ceramics, diamond, and hardmetal composites such as cobalt-bonded tungsten carbide.
 It will be apparent that a stick of a suitable diameter to allow sufficient flexure will generally be too small to grip comfortably, so in most cases it will be preferred to have a hand grip 12 on the upper end of the stick. Hand grip 12 may be of the type conventionally used on ski poles, and may be mounted on a substantially straight stick. Alternatively, the end of the stick may be bent at an angle to provide a more natural grip. As shown in FIGS. 2 and 3, when fitted with a bent hand grip, the pole may be used in two ways. In FIG. 2, the user grasps the lower part of the handle and pushes downward to engage the ground as would be done in conventional Nordic walking or hiking. The pole will tend not to flex unless a sufficiently large force is applied to induce buckling. However, if the hand grip is grasped on the upper part, which is angled with respect to the axis of the pole, any downward force will immediately induce bending of the pole in a controllable way, as shown schematically in FIG. 3.
 The stick of the preceding example was fitted with a hand grip 12 as follows: A length of PVC tubing (˜22 mm o.d.) was heated and bent about 40° in the middle. Stick 10 was adhesively bonded to the inside of the bent PVC tube. A compliant tool grip (Soffoam Grips, Sinclair and Rush, Inc., Arnold, Mo. 63010) was then slipped over the PVC tube to provide a comfortable and slightly compliant gripping surface.
 It will be appreciated that many other means of creating a compliant grip may be used. For example, layers of tape such as that used on bicycle handlebars may be used, as well as other grips such as hand grips used on bicycles, motorcyles, wheelbarrows, and the like. The hand grip may include indentations to accommodate the user's fingers, and a retaining strap or handsling as are often used in ski poles. It will be further appreciated that the invention is not limited to a particular angle of bend in the gripping region.
 A series of tests were conducted to quantify the flexure of various materials, as shown in the following table. The stick material was supported at two ends and various weights were applied at the center of the span. Downward deflection was measured at that point. Tests used a fairly rigid aluminum pole material ("Swissgear-Anti-shock" three-piece adjustable height aluminum pole) with a span of 108 cm, and two polymer stick materials, (1) a diameter of 0.92 cm (0.312 in.) and a span of 109 cm; and (2) a diameter of 0.95 cm (0.375 in.) and a span of 127 cm.
TABLE-US-00001 Aluminum Polymer (1) Polymer (2) Weight, kg deflection, cm deflection, cm deflection, cm 1.36 0.6 5.72 4.76 2.73 1.27 10.48 8.89 4.56 1.91 15.24 14.0 5.45 2.54 17.14 17.8
 One can see that the polymer sticks provide a significantly greater degree of flex, up to ˜17%, for a given load than does the aluminum stick, which deflects up to ˜2.5% under the maximum load applied in this test. It will be appreciated that the properties and dimensions of the stick may be adjusted to meet the needs of a particular user; for instance, one use might prefer a more vigorous workout and therefore will want a pole that requires more load to deflect by the desired amount of bend, whereas, another user might prefer a pole that requires less load to make it deflect by the desired amount of bend. A weaker or more flexible shaft might be indicated, for example, for elderly users or those undergoing various rehabilitative activities. In general, Applicant prefers that the pole will deflect elastically by at least 2%, and more preferably by at least 4% as defined by the deflection from the centerline at the midpoint of the stick.
 Referring to FIGS. 2 and 3, a user is shown gripping the inventive stick in hand. When the handle is grasped on the lower portion, FIG. 2, the inventive stick functions much like any other walking aid, although the shaft retains some flexibility. However, when the user grips the inventive stick at the upper end of the handle, a bending moment is naturally induced in the stick, causing it to flex. When one stick is planted on the ground and flexed, as shown schematically in FIG. 4, the bending moment 20 applied to flex the stick is accompanied by a resultant bending moment 21 on the upper body, which is resisted by tightening of the abdominal and related muscles 22. The user will typically plant the sticks ahead of or alongside the feet, flex the sticks, and then allow them to unflex in a controlled way while maintaining some tension.
 The invention may also be used indoors in various ways. The user can simply plant the tips in any convenient place on the interior surface of the room, such as at the intersection of wall and floor, and flex them in various ways to provide an upper body workout or for limbering up after spending time seated at a workstation, for instance.
 Alternatively, somewhat shorter sticks (˜75 cm) may be used by elderly users who might be confined to a wheelchair, or might simply wish to remain seated for better balance.
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