US20080076646A1

US20080076646A1 - Fast arm-swing tether

Info

Publication number: US20080076646A1
Application number: US11/526,288
Authority: US
Inventors: Andrew W. Chow
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-25
Filing date: 2006-09-25
Publication date: 2008-03-27

Abstract

Fast Arm-Swing Tether supports lower arms and allows a runner or walker to maintain maximum stride frequency. Tethered thumbs/hands raise natural frequency of pendulum motion of arm swing to ensure that stride rate is not limited by slow arm movement. The tethers keep hands and arms up and reduce lower-arm moment of inertia, thus allowing the lower arms to swing essentially as point masses, resulting in a higher natural frequency of pendulum motion of arm swing to ensure stride frequency is not limited by slow arms. Supporting the hands also reduces effort required to swing arms or to keep elbows locked. This invention relieves arm fatigue for long distance running or walking in addition to allowing greater arm movement. Fast Arm-Swing Tether could be made in any fashion as long as a frontal extension can provide adequate support to hang pendulum tethers to keep hands elevated.

Description

BACKGROUND OF THE INVENTION

A classical freshman physics class multiple choice problem poses the following scenario with two almost identical pendulums, both having the same length and the same mass at the end. However, the mass on the first pendulum is a point mass whereas the mass on the second pendulum is distributed as a disk although with exactly the same amount of mass and same location for its center of gravity. With ω as that natural frequency of oscillation, the multiple choices are 1) ω of first pendulum is higher than ω of second pendulum, 2) ω of first pendulum is lower than ω of second pendulum, and 3) ω of first pendulum is same as ω of second pendulum.
The correct answer is 1, with the first pendulum swinging faster than the second pendulum. As a short answer, the distributed mass of the second pendulum has greater moment of inertia and thus a slower natural frequency. Put it another way, if both pendulums are displaced and released from the same height, the same gravitational potential energy would be converted to kinetic energy at the lowest point. The kinetic energy of the first pendulum is just the point mass swinging as a pendulum, but the second pendulum has the same amount of mass swinging as a pendulum plus the rotational energy of the disk. Since both pendulum must have the same total kinetic energy, the second pendulum has to swing slower as part of its gravitational potential energy is shared in disk rotation.

BRIEF SUMMARY OF THE INVENTION

A good runner or walker (for simplicity, runner is used from here on to denote both running and walking) would never consider running with a set of dumbbells, or hand weights. Since the weights slow arm swings and hand movement, dropping them would allow quicker hands and corresponding strides, at a faster rhythm than with the hands weighed down. If a runner can go faster by discarding hand weights, should it not follow immediately that even faster results may be feasible with additional hand-weigh reductions, like chopping off the hands? While we would like to improve performance, amputation seems to be a rather drastic extreme.
Fast Arm-Swing Tether (hereinafter FAST) provides the same effect but without loss of hand usage. FAST supports the lower arms and allows a runner to maintain high stride frequency. FAST keeps hands and arms up and virtually eliminates effect of lower-arm moment of inertia, thus raising the natural frequency, of pendulum motion of arm swing to ensure stride frequency is not limited by slow arms. Elevating hands also reduces the effort required to swing arms or to keep elbows locked. FAST relieves arm fatigue for long distance running in addition to allowing greater arm movement. FAST could be made in any fashion as long as a frontal extension support can provide adequate rigidity and stability to hang pendulum tethers to keep hands elevated.

DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows schematically a typical runner's arm in a neutral at-rest position.

FIG. 2 shows schematically a pendulum-supported arm in a resting position.

FIG. 3 shows movement of pendulum-supported arm from FIG. 2.

FIG. 4 shows a FAST means to effect results from FIGS. 2 and 3.

FIG. 5 shows another FAST means to effect results from FIGS. 2 and 3.

DETAIL DESCRIPTION OF THE INVENTION

FIG. 1 schematically illustrates a runner's arm configuration with elbow bent. In this neutral at-rest position, the elbow is pushed back due to center of gravity of bent-arm configuration. A pin joint represents the runner's shoulder. As the runner swings arms in synch with each stride, the elbows are locked with the arms moving as rigid bodies from the shoulders. Thus the lower arm swings as a pendulum around the shoulder, plus the lower arm rotates around itself in the same way as the second multiple-choice pendulum disk would from the foregoing discussion.
FIG. 2 depicts schematically this invention's at-rest position whereby a runner's hand or thumb is supported by pendulum 10 which is hung from support 20. The configuration in FIG. 2 differs from FIG. 1 as the supported lower arm permits elbow relaxation, giving rise to totally new arm-swing movement as shown in FIG. 3. As pendulum and upper arm swing about parallel to each other, the pendulum, lower arm, and upper arm move in unison and keep an approximate parallelogram relationship. Therefore, the configuration in FIG. 2 has created a form of arm movement without lower arm rotation around itself, thus essentially eliminated the lower arm's moment of inertia effect on arm swing frequency. Therefore, FIG. 2 has transformed the lower arm to simulate the earlier discussion's pendulum point mass to facilitate a faster frequency without resorting to amputation.
Thus pendulum 10 and support 20 in FIG. 2 represent the heart of the present invention with aim to increase arm-swing frequency and the associated running rhythm and speed. While pendulums are easily produced, the challenge is to provide an effective means to hang pendulums in front of a runner's chest. FIG. 4 illustrates a means to achieve such results.
As a schematic side view of shoulder pads that provide the essential elements of FIG. 2, FIG. 4 depicts chest plate 30 and shoulder rest 40. With shoulder pads worn by a runner, front extension 50 extends in front of chest and provides support to hang pendulum 60 with an end loop for thumb or hand. Of course, the apparatus has two pendulums 60, one for each arm. The shoulder pads would be similar in concept to those worn by football players but with less padding, bulk, and weigh.
FIG. 5 illustrates another approach to effectively provide the support 20 from FIG. 2. Pendulums 110 and 120 hang from support 130 which is the top part of a frame. Pendulums 110 and 120 have end loops to support the runner's hands or thumbs. Frame bottom 140 presses against a runner's chest and is held in place by strap 150 which is looped around the back of a runner's neck 160. Downward forces tributary to relaxed arms hanging on pendulums 110 and 120 pull support 130 away from runner's chest, and support 130 is held in place by strap 170 which is also looped around the back of the runner's neck.
It should be obvious to designers knowledgeable of the art that the FAST invention could take many forms, for example by adapting an extension support that is attached to a sports bra's underwire. However, all forms must rely on the heart of this invention, pendulum 10 and support 20 from FIG. 2, and on the physics that differentiates a point mass from a disk. It also should be obvious to physicists knowledgeable of the art that shortening the pendulum would further increase natural frequency of oscillation of supported lower arm, although a shortened pendulum in comparison to length of upper arm would distort somewhat the approximate parallelogram shape.

Claims

1. A fast arm swing device for walking or running comprising

an apparatus worn by an athlete having rigid extension support and two pendulums;

with said pendulums each having a loop to support thumbs or hands;

with said rigid extension support located in front of and away from chest;

with the rigid extension support effective to hang the pendulums and lower arms;

with the pendulums keeping about parallel to upper arms; and

with each group of pendulum, upper arm, and lower arm swinging together to form about parallelogram shape.