Abstract:
A hand-held device comprising a central hollow elongated central member partially filled with a granular material, enclosed at both ends by removable and interchangeable end caps. During the range of motion when exercising, the device can place an additional, low-impact load on muscles, while also providing a rhythmic enhancement to a workout.

Description:
CLAIM OF PRIORITY 
   This application claims the benefit of U.S. Provisional Application No. 60/710,821, filed Aug. 25, 2005, the complete contents of which is hereby incorporated by reference herein. 

   BACKGROUND 
   1. Field of the Invention 
   The present disclosure is for a device that aids in muscle training, strengthening, and development. 
   2. Background 
   Physical training with weights improves muscle tone and strength by placing an additional repeated load on the muscle beyond that produced by the mass of the limb itself. Forcing the muscle to work harder with an additional load helps the muscle to develop faster than if exercised without an additional load. Further, the amount of weight can be increased as strength progresses to keep the workout challenging and beneficial. 
   In aerobic training, adding weights to a person&#39;s limbs helps to strengthen muscles while performing a cardiovascular workout. Adding weights can help to work muscles not already being exercised by the cardiovascular activity, as well as make the workout more challenging. For example, a runner can carry hand weights to get an upper-body strength workout while running. 
   In aerobics, jazzercize, or other similar fitness classes, participants perform a series of choreographed movements, often to music, to improve cardiovascular fitness and strengthen and tone muscles. Holding weights places an additional load on the muscles to make the workout more challenging and further strengthen and tone the muscles. However, holding a dead weight can cause injury with fast motions, particularly at the end of the range of motion for a limb. For example, rapidly extending an arm with a dead weight held in the hand can result in a jolting impact to or hyperextension of the elbow joint, possibly injuring the ligaments supporting that joint, as well as potentially straining the other muscles and tendons of the arm and shoulder. 
   During exercise, listening to music helps with pace and rhythm, as well as provides motivation. Although a participant in an aerobics class, for example, can hear the music playing and move accordingly, having a personal rhythm device can keep a person more in touch with the beat of the music. Holding a shaker or other device that the user must move in time with the music provides a kinesthetic connection to the music. 
   What is needed is a device that allows users to place an additional, low-impact load on a muscle, while providing a rhythmic benefit while exercising. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  depicts a side view of an embodiment of the present device. 
       FIG. 2  depicts a perspective view of an embodiment of the present device. 
       FIG. 3  shows another embodiment of the present device with an end cap removed. 
       FIG. 3   a  shows an alternative embodiment of an end cap having a different cross-section than that of the central elongated member. 
       FIG. 4  shows an alternative embodiment of the present device with an additional member to secure the device to a person&#39;s extremity. 
       FIG. 5  shows an alternative embodiment of the present device with an adjustable stopper mechanism. 
       FIG. 5   a  depicts a side cutaway view of the embodiment shown in  FIG. 5 . 
       FIG. 6  shows a method for conducting a group exercise activity with embodiments of the present device. 
   

   DETAILED DESCRIPTION 
     FIG. 1  depicts an embodiment of the present device. An elongated hollow central elongated member  102  can be partially filled with a quantity of granular material  104 . End members  106  can close the open ends of the hollow central elongated member  102 . Stoppers  108  of cross-sectional dimensions and cross-sectional area slightly less than that of the interior cross-sectional dimensions and cross-sectional area of the hollow region of the central elongated member  102  and of length less than half the length of the hollow central elongated member  102  can be substantially aligned with the longitudinal axes of the hollow central elongated member  102  and the end members  106 . 
   The central elongated member  102  can be made of plastic, rubber, polymer, metal, or any other known and/or convenient material. The material can have an inherent texture to improve comfort and/or grip, or in some embodiments an additional covering or coating can provide these properties. The central elongated member  102  can be substantially straight, as shown in  FIG. 1 , or curved to any known and/or convenient radius. Further, the cross section of the elongated central elongated member  102  can be circular, as shown in  FIG. 1 , or any known and/or convenient geometry. 
   The granular material  104  can be any known and/or convenient material, such as, but not limited to, polymers, plastics, or metals. The volume of the quantity of granular material can be less than 25% than that of the volume of the hollow region of the central elongated member  102  with the stoppers  108  in place. 
   In some embodiments, as shown in  FIG. 1 , the end members  106  can be caps that cover the open ends of the hollow central elongated member  102 . However, the end members can be any known and/or convenient configuration to effectively close the open ends of the hollow central elongated member  102 . They can be permanently coupled with the hollow central elongated member  102 , thereby permanently sealing it. In other embodiments, they can be removably coupled by a screw coupling, friction fit, magnetic coupling, or any other known and/or convenient mechanism. Further, the end members  106  can be made of plastic, rubber, polymer, metal, or any other known and/or convenient material. 
   In some embodiments, the stoppers  108  can be attached to the end members  106  such that when the end members  106  are coupled with the ends of the central elongated member  102  the stoppers  108  set into the hollow region of the central elongated member  102 , thereby making the length of the hollow region less than that of the central elongated member  102 . The stoppers  108  can be made of plastic, rubber, polymer, metal, or any other known and/or convenient material. 
     FIG. 3  shows another embodiment of the present device, wherein at least one of said end members  106  can be removable. Further, in some embodiments, the stoppers  108  can also be removable. 
     FIG. 3   a  shows another embodiment of an end member  106 , wherein it has a substantially square-shaped cross-section. In other embodiments, the end members  106  can have any known and/or convenient polygonal cross sections that may or may not be different from the cross section of the central elongated member  102 . Further, the end members  106  can be produced in different weights and can be made of plastic, rubber, polymer, metal, or any other known and/or convenient material. 
   In embodiments having removable end members  106 , said end members  106 , stoppers  108 , and the granular material  104  can be replaced by additional interchangeable components. End members  106  can be replaced by alternative interchangeable end members  106  having different colors, weights and/or shapes. Stoppers  108  can be replaced by interchangeable stoppers  108  having different lengths. The granular material  104  can be replaced with an alternate granular material  104  having a different density, thereby changing the weight of the granular material  104  within the hollow central elongated member  102 . 
     FIG. 4  shows another embodiment of the present device including a securing member  402  affixed to the exterior surface of the hollow central elongated member  102 . In some embodiments, a securing member  402  can be a fixed or adjustable strap. A securing member  402  can also be any known and/or convenient mechanism for securing the present device to a person&#39;s limb or extremity. In some embodiments, a securing member  402  can be a loop or tether affixed substantially near one end of the hollow central elongated member  102 . A securing member  402  can be permanently or removably attached to the hollow central elongated member  102 . 
   In some embodiments, the present device can have adjustable stoppers  108 . As shown in  FIG. 5 , the end members  106  can be rotated to move the stoppers along the longitudinal axis of the central elongated member  102 . The stopper  108  can be affixed to a threaded shaft  502  located substantially along the central axis of the stopper  108 . A disk having a threaded central hole  504  can be affixed to the open end of an end member  106  proximal to an end of the central elongated member  102 . An end member  106  can have an inward-turning turning flange  506  on said open end of an end member. The central elongated member  102  can have a circumferential groove  508  located substantially near an end of the central elongated member  102 . 
   When assembled, the stopper  108  sits inside the hollow portion of the central elongated member  102 , while the threaded shaft is coupled with the threaded hole in the disk  504 . An end member  106  is coupled with the central elongated member  102  such that the flanged edge of the end member  106  sits in the circumferential groove  508 . Rotating an end member  106  about the central axis of the device rotates a disk  504  such that the threaded hole and shaft coupling translates the rotational motion to longitudinal motion of a stopper  108  via the threaded shaft In other embodiments, a ratchet or any other known and/or convenient mechanism can lock said end member  106  in place. The coefficient of friction between the lateral edges of a stopper  108  and the interior walls of the hollow central elongated member  102  can be such that rotational motion of a stopper  108  is prevented. Therefore, as an end member  106  is rotated, the corresponding stopper  108  can be adjusted to change the length of the interior hollow region of the central elongated member  102 . Although shown in  FIG. 5  with a screw mechanism to adjust the stopper  108  position within the central elongated member  102 , any other known and/or convenient mechanism can be used to adjust the stopper  108  position. 
   In operation of one embodiment, a user grips the central elongated member  102 . As the user moves her arms in flexion and extension, the granular material  104  shifts within the hollow portion of the central elongated member  102  in the direction of the motion. The mass of the granular material  104  places an additional mechanical load on the muscles involved in the motion. As the device accelerates and decelerates through the range of motion, the granular material  104  travels down the length of the hollow portion of the central elongated member  102 . The granular material  104  impacts the end of a stopper  108  that has been inserted into the hollow portion of the central elongated member  102 . The force of this impact creates a reaction force that is exerted on the muscles, thereby increasing the mechanical load experienced by these muscles. Increasing the mechanical load on the muscles during the range of motion can enhance the challenge of the workout and improve muscle development. In other embodiments, a user could attach the device to a foot or other part of the leg while participating in a lower-body workout to achieve the same effect. 
   The impact force, and subsequent reaction force exerted on the muscles, is created by the mass of the granular material  104  decelerating when it impacts the end of a stopper  108 . However, in contrast to a dead weight, which all travels at the same speed and decelerates at the same time, the particles of the granular material  104  decelerate differently, thereby spreading out the time of impact of the total mass of granular material  104 . By spreading out the time of impact, the reactive force, and therefore the additional mechanical load exerted on the muscles is not experienced as a jolt, but as a gentler force. This can decrease the likelihood of injury to muscles and connective tissues experiencing the increased mechanical load. 
   In embodiments with removable end members  106 , a user can change the end members  106 , stoppers  108 , and/or the granular material  104  to customize the device to an individual&#39;s exercise needs. Increasing or decreasing the weight of the end members  106  or the stoppers  108  can provide more or less resistive force to the muscles. Changing the length of the stoppers  108  to vary the length of the hollow portion of the central elongated member, as well as changing the density and/or volume of the granular material  104  can alter the impact dynamics of the granular material and the resulting reaction force exerted on the muscle. End members  106  can also be interchanged for different colors to provide aesthetic appeal. In an embodiment with a substantially transparent or translucent hollow central elongated member  102 , different colors of stoppers  108  and/or granular material  104  can provide further aesthetic enhancement. 
   In addition to the mechanical load placed on the muscles, the movement of the granular material  104  within the hollow central elongated member  102  can also produce a rhythmic sound in response to the user&#39;s movements. The sound component of the present device can strengthen the user&#39;s connection to the music, which can provide motivation and pacing during the workout. Further, the sound can provide auditory feedback to the user regarding the force and tempo of her motions and help her to keep in sync with the music. Alternatively, in other embodiments a user can use the device in the absence of music to create her own rhythm sounds during a workout. 
   As shown in  FIG. 6 , embodiments of the present device can also create a rhythmic group exercise experience. Embodiments of the present device can be distributed to members of a group  602 . Music can be provided for the group to follow and to which the group performs a series of movements  604 . Movement of embodiments of the present device  606  during the exercise can produce a group rhythmic sound, which can help to keep the group members in sync, as well as provide a motivational and pacing beat  608 . Alternatively, exercise can be conducted to produce syncopated rhythms and beats among sub-groups or individual members of the group  608 . 
   Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the invention as described and hereinafter claimed is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.