Abstract:
A device for promoting reflective neuromuscular training. The device is a moderately compressible member having a planar lower surface and an incongruent upper surface. When used in proprioceptive rehabilitation, the device stimulates sensory pathways to improve balance and neuromuscular responses.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit from U.S. Provisional Patent Application Ser. No. 60/566,259, filed Apr. 29, 2004, and also U.S. Provisional Patent Application Ser. No. 60/604,639, filed Aug. 26, 2004, which applications are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates generally to the therapeutic devices and, in particular, to a device which promotes reflective neuromuscular training.  
         [0004]     2. Description of the Related Art  
         [0005]     Devices which are used to strengthen, rehabilitate, and exercise the feet, ankles, and lower extremities are commonplace today. One type of these devices are generally used for exercising and strengthening the foot. For example, U.S. Pat. No. 1,962,971, which issued in 1934, describes a foot treating device comprising a conoidal-shaped body of flexible resilient material terminating in flanges of sufficient radial extent to bear laterally against and massage the sides of the foot when rolled, exercising the muscles and stimulating weakened nerve tissues. U.S. Pat. No. 2,510,193, which issued in 1950, describes a foot exerciser which is rolled beneath the feet to exercise the feet to cause the weakened muscles and bones of the feet to return to their normal positions and strengthen them in their positions. U.S. Pat. No. 2,465,725, which issued in 1949, is directed to a foot exerciser pad consisting of a multiplicity of resilient, button-like members, preferably of uniform size which exercises the muscles of the feet and legs by rocking the feet as the rounded buttons occupying the spaces formed by the arches of the feet. U.S. Pat. No. 2,820,454, which issued in 1958, is directed to a foot kneading rug comprised of a base pad of sponge rubber on which hard buttons are mounted in distributed arrangement, where the buttons are of spherical segmental shape of a thickness approximated equal to the thickness of the sponge rubber pad. The composite surface formed by the rounded upper portions of the hard buttons and the intervening soft depressions formed by the exposed upper surface of the pad is covered intimately by a cover membrane forming the rug tread.  
         [0006]     While these devices are capable of exercising and strengthening the muscles of the feet, they do not develop proprioception. Proprioception involves neuromuscular receptors in the skeletal muscles on the surface of the tendons. These receptors provide constant feedback to the brain regarding movement, posture, changes in equilibrium, knowledge of position, weight and resistance against its body parts. Special devices have been developed in recent times which address this function. U.S. Pat. No. 6,551,225, which issued in 2003, is directed to a balancing exercise device having a flexible hemisphere having a flat circular surface and a hemispherical side surface and attachment straps such that a body part is held against the flat circular surface. Constant variations of movement in any and all directions of the hemispherical surface put different stretch on the tendons, muscles, ligaments and joints and thereby stimulates increased numbers of proprioceptors and nerve cells of the body parts. U.S. Pat. No. 6,811,523, which issued in 2004, describes a lower extremity rehabilitation and exercise device having a platform to which at least one foot is secured. A fulcrum is placed beneath the platform at various locations which correspond to particular muscles or muscle groups which are stressed while the exercise is performed, building strength in the muscles, while also developing proprioception within the stressed muscle or muscle group during the exercise. While these devices are relatively simple to use, they rely on balancing the body on a flat surface which is mounted upon a hemispherical shape while the feet are strapped to a flat surface.  
         [0007]     Another type of device has also been developed for the purpose of improving proprioception in the user. U.S. Pat. No. 5,613,690, which issued in 1997, describes a training and enhancement device to improve the balance and proprioceptive abilities of the user. A balance platform is placed atop a base platform, with the balance platform being angularly displaceable in any direction relative to the base. The device is connected to a personal computer through sensors, providing feedback to determine angular displacement of the user. U.S. Patent Application Publication No. 2003/0199374, which was published in 2003, describes a proactive machine for assessing and improving a user&#39;s proprioception. The device has a tilting platform upon which the user stands, a non-rotating tilting means connected to the platform for tilting the platform along several axes, and a control for controlling the tilting. While these devices are designed specifically for promoting proprioception improvement, these are relatively complex and expensive to purchase.  
       SUMMARY OF THE INVENTION  
       [0008]     It is therefore an object of the present invention to provide a therapeutic device which is inexpensive and portable.  
         [0009]     It is a further object of the present invention to provide a rehabilitative device for promoting improved balance and proprioception training in the feet, ankles, knees and hips.  
         [0010]     It is a still further object of the present invention to provide a device which may be incorporated into an exercise routine for enhancing balance and proprioception.  
         [0011]     It is a still further object of the present invention to provide a device which provides preloading of the soft tissues of the foot and ankle prior to exercising to prevent injury to these areas.  
         [0012]     These and other objects of the present invention will become readily apparent from the description and drawings which follow. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a side elevational view of a device according to the present invention;  
         [0014]      FIG. 2  is a side elevational view of an alternative embodiment according to the present invention;  
         [0015]      FIG. 3  is a front elevational view of the device shown in  FIG. 1  in use;  
         [0016]      FIG. 4  is a side elevational view of the device shown in  FIG. 2  in use; and  
         [0017]      FIG. 5  is a top plan view of another alternative embodiment of the present invention for use in rehabilitation of a patient. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Balance and postural control are complex processes that rely on input from three systems: the visual system, which orients oneself to an object, the vestibular system, which orients oneself to gravity, and the somatosensory system, which refers to the premeditated and/or the unconscious awareness of joint position. This plays an important role in the prevention of injury, as well as in maintaining the integrity of joint and surrounding anatomical structures. Sensory receptors for proprioception relay the status of articular (oint) structures. These receptors, or fibers, are found in the skin, muscles, joints, joint capsule, ligaments, and tendons, and send information to the central nervous system concerning joint movement (kinesthesia) and joint position (proprioception). Four types of joint sensory fibers have been identified, each serving a specific role in sensorymotor function and joint proprioception: type I fibers (located in the joint capsule) provide information concerning static (stationary) position and help regulate postural muscle tone; type  11  fibers (located in joint capsule) detect quick changes in movement and provide information concerning acceleration and deceleration of joint components; type III fibers (located in the intrinsic and extrinsic joint ligaments) monitor direction of movement and have a reflex effect on muscle tone to prevent excessive motion or displacement of the joint; and type IV fibers (located in the capsule, and intrinsic and extrinsic ligaments) are inactive under normal circumstances, but may be activated when related tissue is subjected to marked deformation or other noxious mechanical or chemical stimulation. Skin connective tissue and muscle nerve endings (mechanoreceptors) may also contribute information in these ways.  
         [0019]     Sensory (afferent) information is relayed to the central nervous system via the sensory receptors previously discussed, is processed by the brain, and an appropriate motor response is initiated to maintain balance or stabilize a joint. Two motor control mechanisms are involved with interpreting afferent information and coordinating an efferent (to joint structures) response; feed-forward and feedback. Feed-forward involves planning movements based on sensory information from past experiences (preparatory muscle activity). This pre-activation theory suggests that prior sensory experiences concerning a task are used to form muscle activity patterns. In this way, sensory feedback from the past is fed forward to pre-program muscle responses. The feed-forward mechanism causes pre- activated muscles to provide quick compensation for external loads, which is critical to dynamic joint stability. The feedback mechanism continuously regulates motor control through reflex pathways and reactive muscle activity. Information from joint and muscle structures is used reflexively to synchronize motor responses to complete a task. The feedback process is best used to maintain posture and regulate slow movements. The influence of this process on dynamic joint stabilization is dependent upon the speed and magnitude of joint perturbations. Both feed-forward and feedback mechanisms enhance joint stability if these motor pathways are frequently stimulated by way of proprioceptive or rehabilitative training. With repetitive stimuli, these pathways create memory in the joint for future movements.  
         [0020]     At the joint structural level, individuals who are well-conditioned have better joint motion and position sense than those who are deconditioned. The deconditioned persons lack adequate somatosensory awareness to coordinate muscle activity and dynamic joint stability, and may be subject to injury. Speed and complexity of movement in activities of daily living rely on rapid integration of sensory information by the feed-forward and feedback mechanisms. Without sufficient preliminary activity, or training, structures of the joint and extremity may become vulnerable to damage. An injury, mechanical or disease-related, causes partial deafferentation (decreased sensory input) of the joint. Deafferentation is a decreased afferent neural signal, and is described as a proprioceptive deficit. Decreased proprioceptive signals inhibit normal motor response and balance reactions and decrease neuromuscular stabilizations of the joint, which may lead to injury or further damage of joint structures.  
         [0021]     The purpose of neuromuscular rehabilitation for proprioceptive deficits is to incorporate peripheral sensory input relative to joint position, and to process these signals into efferent motor responses. Once proprioceptive deficits have been identified, they need to be corrected in order to prevent episodes of functional instability and repetitive injury. Rehabilitation for these deficits should encourage preparatory agonist (contracting) and antagonist (opposing) muscle activity. Effective co-activation restores the force couples required to balance joint forces and increases congruency, thus reducing loads on joint structures. In a controlled rehabilitation exercise, the placement of joints in vulnerable, or unstable, positions helps re-establish proprioception and appropriate motor responses. These stabilizing responses of muscles require sensory anticipation of joint displacement and joint loads. Therefore, neuromuscular and balance training focus upon stimulating the sensory pathways from joint structures to the central nervous system. Frequent or repetitive use of these pathways has been shown to decrease response time and develop reaction strategies for unexpected events. Reflex-mediated muscle activity is a crucial element of the functionally stable joint and should complement pre-programmed activity. Proprioceptive rehabilitation should focus upon neuromuscular training by stimulating the reflex pathways from joint structures (ligaments, tendons, cartilage, capsule, epidermis) and surrounding muscles that act as static and dynamic stabilizers. Therefore, proprioceptive and balance exercises should provoke joint perturbations (alterations of position) to facilitate reflex muscle activation and postural control. By creating postural and/or dynamic imbalance, these rehabilitation activities encourage automatic and appropriate neuromuscular responses. Thus, these types of exercise should be initiated early in all rehabilitation programs. Patient involvement, by way of home exercises and exercise tools, is also critical to the success of the rehabilitation program.  
         [0022]     It is important, finally, to mention the role of proprioceptive and balance training in post-surgical or post-injury tissue healing. Research has indicated that joint structures increase in strength linear to stresses put upon them (Wolfe&#39;s Law) and, also, that there is a strong relationship between joint injury and subsequent loss of motor control. It is essential, then, to stress these structures in a functional manner during rehabilitation to promote the proper orientation of joint tissue fibers during healing. Selective proprioceptive exercises which simulate realistic tasks can encourage healing of tissues in the same orientation of functional stresses applied to the joints with everyday activities. Thus, proprioceptive training provides a protective mechanism against re-injury with return to activity.  
         [0023]     The present invention comprises materials, or tools, used to elicit joint perturbations and therefore promote reflective neuromuscular training. The dense, irregular foam rubber and rock-like shape of the device provides a means of stressing or compressing different soft tissues of the foot, or any other extremity, placed upon them. Depending upon the position of the extremity of the device&#39;s surface, muscle activation occurs through proprioceptive information to the central nervous system and muscular response to maintain joint stability near stressed structures. At the same time, reciprocal inhibition (relaxation of antagonist muscle) occurs in the muscle groups not stressed. (i.e. quadriceps contract, hamstrings relax) This co-activation of muscle groups helps to balance the forces surrounding the joint, and, as research has shown, plays a key role in prevention of injury to susceptible tissues (i.e. a knee after ligament surgery). Lastly, the forces applied to the distal (furthest end from the torso) extremity by way of the device also provides neuromuscular training for more proximal (closest end to the torso) structures. Activity from these proximal structures is required to maintain overall balance and postural stability. Therefore, forces from the device applied to the foot, or hand, can provide neuromuscular training for the ankle, knee, and hip, or the forearm, elbow, and shoulder. Many studies have documented that the body does not function as a rigid segment, but as a multi-link structure; events surrounding the distal segment of an extremity affect those located more proximally in the kinetic chain. Thus, the use of the incongruent surface of the device is a crucial element in retraining the sensory pathways to the central nervous system from multiple anatomical structures, so that this information may be stored and retrieved at the appropriate time in the future (with return to activity or sport). The various sizes and points of application of the device provides a multitude of opportunities for this type of physical rehabilitation. Finally, the fact that the device is both affordable and easily transported make it an ideal home exercise tool, which could complement virtually any neuromuscular or orthopaedic training program.  
         [0024]     Referring now to  FIG. 1 , there is shown a device, generally indicated at  10 , which embodies the present invention. Device  10  contains a planar lower surface  12  for positioning device  10  on a flat horizontal surface such as the floor or an exercise mat. Upper region  14  of device  10  comprises an irregular incongruent surface. Device  10  is preferably constructed from a dense foam rubber which moderately compresses when subjected to the weight of a user. The incongruent surface may contain certain surface features, such as a concave or convex section, in areas of the surface to enhance proprioception training for specific areas of the body.  
         [0025]      FIG. 3  shows device  10  in use, with the foot  20  of a user standing on device  10 . Note that the irregular surface  14  allows some compression of device  10 , causing various points of application to the bones, muscles and tendons of the user&#39;s foot. When the user balances on one foot on device  10 , the brain sends messages to various muscles of the body, instructing them to correct the instability. In this manner, proprioceptive deficits can be rehabilitated. If the user looks from side to side while balanced, additional proprioceptive information will be sent to the central nervous system, and reaction to this stimulus creates additional rehabilitative effects.  
         [0026]      FIG. 2  displays an alternative device  10 ′, which exhibits a different upper region  14 ′ that is shown in  FIG. 1 . The overall size of device  10 ′ may be smaller than device  10 , and is preferably constructed of a denser foam rubber which has less compressibility. Device  10 ′ does have a planar lower surface  12 , such that it can be positioned solidly on the floor. When a user&#39;s foot  12  is placed upon device  10 ′ and the body is balanced on foot  12 , different sensory stimulation is accomplished, as the firmness and orientation of device  10 ′, in addition to its non-uniformity of its outer top surface, are different than that of device  10 .  
         [0027]      FIG. 4  shows the device of  FIG. 3  in use, where the user locates device  10 ′ in the mid-foot area. By using the device under different sections of the foot, such as rear foot, mid-foot, and forefoot, other areas of the body including the ankle, knee, and hip structures may be stressed.  
         [0028]     In addition to stretching the muscles of the foot, which is desirable in sports such as running, proprioceptive balance is promoted not only in the foot, but also in the ankle, knee and hip joint.  
         [0029]     This preloading of the soft tissues of the foot and ankle prior to exercising helps to prevent injury to these areas.  
         [0030]     One goal of proprioceptive/balance training is to return patients to their maximum prior level of function. Therefore, systems can be designed containing multiple proprioceptive and a balance related challenges specifically to promote reflective neuromuscular training for any individual. Such a system is shown in  FIG. 5 . Referring now to  FIG. 5 , a training system designated at  30  consists of a plurality of interchangeable interlocking mats of pads  32  which can be assembled to maximize the rehabilitative regimen of each patient. In the center of each pad is a version  10   a - f  of the device shown in  FIGS. 1 and 3 . System  30  contains a mix of multiple proprioceptive and balance related challenges. Each pad  32  differs in degree of proprioceptive/balance difficulty on its surface. For example,  10   a  and  10   d  devices may contain a mild degree of difficulty,  10   b  and  10   e  devices contain a moderate degree of difficulty, and  10   c  and  10   f  devices contain a severe degree of difficulty. Each device may contain an indicia which denotes the degree of difficulty, such as red for simple, blue for difficult, etc. In this manner, clinicians can construct a course using different segments, depending on the patient&#39;s needs. In addition, other compliant surfaces, such as a grasslike surface, or obstacle to step over and around can be inserted into the system to elicit certain neuromuscular responses to suit the patient&#39;s needs. System  30  can be used to simulate the everchanging proprioceptive and balance changes in the environment which patients face every day during the activities of daily living.  
         [0031]     While this invention has been shown and described in terms of a preferred embodiment, it will be understood that this invention is not limited to this particular embodiment, and that many changes and modifications may be made without departing from the true spirit and scope of the invention as defined in the appended claims.