Abstract:
The invention generally relates to footwear for sports, and particularly to a footwear system for improved athletic performance. The invention provides a footwear system for athletes in which elements provide padding and prevent slippage between an athlete and the ground. The elements are arranged according to precision measurements of maximal stresses that occur between the sole of the feet and the ground during an athletic performance. Using a system of the invention, an athlete avoids unpredictable slippage during a performance and also positions their feet consistently, with the result that performance is consistent and commensurate with equipment choice and physical abilities.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of International Patent Application Serial No. PCT/US13/69996, filed Nov. 14, 2013, and of U.S. patent application Ser. No. 13/676,620, filed Nov. 14, 2012, the contents of which are incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention generally relates to footwear for sports, and particularly to a footwear system for improved athletic performance. 
       BACKGROUND 
       [0003]    When an athlete performs, he would like to achieve consistent excellence. Whether the objective is to score goals, maneuver adroitly, or run fast, the athlete wants to maximize performance. In many sports, this requires a complex kinematic performance in which the athlete&#39;s body provides many moving parts that must all be coordinated to give the desired performance. Unfortunately, some athletes do not obtain the best results that they desire. Golfers miss shots, as do basketball players. Baseball players strike out and runners sometimes stumble. 
         [0004]    What is particularly bedeviling is that results can be inconsistent. When an athlete executes a move that is, for all purposes, the same as a move that they made earlier in the same day, sometimes the athlete gets a different result. Even where the athlete knows that they are repeating the same physical motions—the same muscle contractions with the same club in the same weather on the same day—the outcome may be unpredictable. As a result, scores suffer. Not only are the poor scores a source of frustration and displeasure to athletes, but the unpredictability itself can be very vexing. Additionally, athletes experience problems such as discomfort associated with foot pressure and sweat. Playing a sport for a long time can lead to soreness and weariness. Poor weather can create uncomfortable and risky low-traction conditions. All of these factors can have an adverse effect on the athlete&#39;s performance. 
         [0005]    The fact that athletes experience such vexatious and frustrating phenomena is a significant problem facing athletes. 
       SUMMARY 
       [0006]    The invention provides a footwear system for athletes in which elements for traction and padding are arranged according to precision measurements of maximal stresses that occur between the sole of the feet and the ground at different moments throughout an athlete&#39;s performance. The elements may be provided as part of a shoe, an insert, a sock, or a combination thereof. Footwear elements provide traction that opposes lateral stresses while providing cushioning that relieves discomfort associated with compressive stresses. Since discomfort is relieved at just those spots in which an athlete experiences maximal compressive stresses, the athlete does not make continuous or subconscious adjustments of their foot positioning throughout the performance. Since the padding and traction elements are positioned precisely according to measurements of stress during an athletic performance, an athlete experiences maximal comfort by repeatedly positioning their feet consistently in the same way continually and day-after-day. By providing a system that incorporates elements placed according to measurements of maximal stresses, lateral motions between the foot and the ground are prevented. Since lateral motions between the foot and the ground are prevented just at those spots of maximal stress, the athlete plus the Earth form a single mass transferring momentum to the objects the athlete interacts with (e.g., a javelin, a golf ball, a baseball, other players), giving much more predictable, consistent results than an athlete that slips, relative to the Earth. Using a system of the invention, the athlete avoids unpredictable slippage during a performance and also positions their feet consistently, with the result that results are commensurate with equipment choice and physical abilities. Thus the athlete enjoys the rewarding experience that, as their athletic abilities improve, their scores improve. Their experiences in the sport are predictable and pleasurable and athletes can focus on getting the best performance from their equipment. 
         [0007]    The invention includes the insight that stress between an athlete&#39;s feet and the ground can be dynamic and asymmetrical and influenced by the athlete&#39;s choice of footwear. The invention includes models of compressive and shear stresses as distributed across both of an athlete&#39;s feet during a performance. The invention provides templates for footwear systems that incorporate the stress models. A template of stress patterns can be used to provide a sock with cushioning elements, a shoe with cushioning elements, a shoe insole with cushioning elements, or a combination thereof. Because compressive and shear stresses may be non-uniformly distributed across the sole of a foot and asymmetrically distributed between a pair of feet, a template and footwear made accordingly avoids the positioning of non-useful elements in spots where they would not provide benefit and could instead increase discomfort, provide adverse biofeedback incentives, decrease tactile information specificity, or interfere with other material functions such as stretching or breathing. Accordingly, the invention provides sports footwear systems in which a sock and a shoe or an insole interact generally, as well as systems that specifically incorporate patterns of maximal stress. To maximize a consumer&#39;s ability to tune their footwear to their needs, the invention provides whole-footwear systems as well as shoes, socks, or shoe insoles that can be obtained separately and mixed-and-matched according to the athlete&#39;s judgment. 
         [0008]    In certain aspects, the invention provides a sports footwear system that includes one or a pair of shoe inserts. The insert has a plurality of features for padding and traction disposed in an arrangement corresponding to a template provided by measurements of stress exhibited by an athlete&#39;s foot during performance. A side of the insert can be described as including a ball-of-foot portion, a toe portion, a heel portion, an inner arch portion, and an outer arch portion. According to certain measured stress templates, the ball-of-foot portion, the outer arch portion, and the heel portion of the insert each have at least one padding element. Some templates may provide multiple elements for padding and traction (e.g., 2, 3, 4, many) for the ball-of-foot portion, the outer arch portion, or both. The elements may all be of uniform size. In some embodiments, an element on the heel is largest and an element on the outer arch portion is smallest. The insert may optionally include elements to correspond to an underside of a toe of an athlete. In some embodiments, the insert is reversible, with high-relief elements on one side and low-relief elements on the other side. Preferably, the insert is provided as part of a pair. 
         [0009]    The insert and the elements may include an elastomer such as thermoplastic polyurethane (TPU). The elements may be a plurality of discrete elements of one material adhered to a second material providing a main body of the insert, or the insert may be singular areas of material. 
         [0010]    In a related aspect, the invention provides a method of preventing fatigue while playing a sport by wearing a shoe insert that has a plurality of elements for padding and traction. By playing a sport while wearing the footwear, consistent performance is encouraged, in part because the elements of the insert prevent the foot from slipping within a shoe. 
         [0011]    In certain aspects, the invention provides a sports footwear system that includes a shoe and a sock. The shoe has an insole with a plurality of features for padding and traction. The sock—generally including a cuff, a leg, an instep, a toe, a heel flap, and a sock sole, the sock sole having a ball-of-foot portion, an inner arch portion, an outer arch portion, and a heel portion—has a plurality of elements for padding and traction disposed on the sock sole in an arrangement corresponding to the arrangement of the plurality of features of the insole of the shoe. The arrangement may correspond to a template provided by measurements of stress exhibited by an athlete while playing the sport. According to certain measured stress templates, the ball-of-foot portion, the outer arch portion, and the heel portion of the sole of the sock each have at least one padding element. Some templates may provide multiple elements for padding and traction (e.g., 2, 3, 4, many) for the ball-of-foot portion, the outer arch portion, or both. The elements may all be of uniform size. In some embodiments, an element on the heel is largest and an element on the outer arch portion is smallest. The sock sole may optionally include elements to correspond to an underside of a toe of the athlete. Elements for padding and traction may be located strictly on the downward facing area of the sock, or they may extend around up to the side of the sock. In certain embodiments, the sport is golf. 
         [0012]    Each of the padding and traction elements on the sock sole may include an elastomer such as thermoplastic polyurethane (TPU), as may padding and traction elements on the insole of the shoe. The elements may be a plurality of discrete elements of material adhered to the fabric of the sock, or may be singular areas of material. 
         [0013]    In some embodiments, the elements on the sock and the features on the shoe each have a cross-sectional profile designed to interlock with the other to prevent relative lateral motion between the sock sole and the shoe in at least one direction, and optionally more than one, when the system is worn by a person. 
         [0014]    In a related aspect, the invention provides a method of preventing fatigue while playing a sport by dressing in a sock in which a sole of the sock has a plurality of elements for padding and traction and wearing a shoe having an insole with a plurality of features for padding and traction arranged to correspond to the elements. By playing the sport while wearing the footwear, consistent performance is encouraged, in part because the elements of the sock may interlock with the features of the shoe insole to prevent the sock from slipping within the shoe. 
         [0015]    Aspects of the invention also include a sports sock defining a cuff, a leg, an instep, a toe, a heel flap, and a sole. The sole includes a ball-of-foot portion, an inner arch portion, an outer arch portion, and a heel portion. The sole may further include one or more elements for padding and traction located according to a measured pattern of stress exhibited by an athlete&#39;s foot during performance. For example, in some embodiments, the ball-of-foot portion includes a first element for padding and traction, the outer arch portion includes a second such element, and the heel portion includes a third such element. The elements may be of uniform size or the first element has a larger area than the second element while the third element has a larger area than the first element. In certain embodiments, the plurality of elements for padding and traction is disposed on the sole in an arrangement corresponding to a known arrangement of features on an insole of a pre-determined shoe. In certain embodiments, the sport is golf and the elements are located according to a measured pattern of stress exhibited on a golfer&#39;s foot during a golf swing. 
         [0016]    In other aspects, the invention provides methods of making socks. Methods of the invention include receiving a template that shows a pattern corresponding to regions of maximal stress experienced on the sole of an athlete&#39;s foot during an athletic performance and adding elements for padding and traction to the sole of a fabric sock according to the pattern. The method may further include making the sock for example, by knitting it. The elements may be added by screen-printing onto the fabric of the sock. An elastomer such as TPU or other material may be screen printed. The sport may be golf. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  illustrates a shoe insert for sports improvement. 
           [0018]      FIG. 2  gives a cross-section through a shoe insert showing a double-sided embodiment. 
           [0019]      FIG. 3  shows an apparatus for measuring stress between a foot and ground. 
           [0020]      FIG. 4  shows measured stresses between feet and ground during a golf swing. 
           [0021]      FIG. 5  shows vectors of shear stresses between feet and ground during a golf swing. 
           [0022]      FIG. 6  illustrates a sock of embodiments of the invention. 
           [0023]      FIG. 7  depicts a socklet according to embodiments. 
           [0024]      FIG. 8  is a diagram of regions of a sole. 
           [0025]      FIG. 9  depicts a sole of a sock of the invention. 
           [0026]      FIG. 10  shows a sole of a sock according to embodiments. 
           [0027]      FIG. 11  illustrates a sock sole of the invention. 
           [0028]      FIG. 12  shows a sock according to the invention. 
           [0029]      FIG. 13  portrays a sock according to certain embodiments. 
           [0030]      FIG. 14  exhibits a pair of socks according to embodiments of the invention. 
           [0031]      FIG. 15  demonstrates a pair of socks according to certain embodiments. 
           [0032]      FIG. 16  displays an exemplary pair of socks of the invention. 
           [0033]      FIG. 17  reveals a pair of socks according to embodiments. 
           [0034]      FIG. 18  is a reproduction of results of measuring sole stress during a golf swing. 
           [0035]      FIG. 19  is a contour diagram of regions of stress shown in  FIG. 16 . 
           [0036]      FIG. 20  is a flowchart of a method of improving a golfer&#39;s game. 
           [0037]      FIG. 21  shows an exemplary system for improving a golfer&#39;s game. 
           [0038]      FIG. 22  is a detailed diagram of regions of a sole. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]      FIG. 1  illustrates a shoe insert  1  for improved performance in sports. Shoe insert  1  may be provided for any sport such as, for example, soccer, football, golf, baseball, running, motorsports, fitness, sailing, cricket, rallycross, etc. Insert  1  has a plurality of elements  13   a ,  13   b , . . . ,  13   n  for padding and traction disposed in an arrangement corresponding to a template provided by measurements of stress exhibited by an athlete&#39;s foot during performance. Insert  1  includes a ball-of-foot portion, a toe portion, a heel portion, an inner arch portion, and an outer arch portion (see  FIG. 8  and accompanying description). According to certain measured stress templates, the ball-of-foot portion, the outer arch portion, and the heel portion of the insert each have at least one element  13 . Some templates may provide multiple elements  13  for padding and traction (e.g., 2, 3, 4, many) for the ball-of-foot portion, the outer arch portion, or both. Elements  13  may all be of uniform size. In some embodiments, element  13  at the heel is largest and an element  13  on the outer arch portion is smallest. In a preferred embodiment, each element  13  includes 18 protruding dots (e.g., as shown as element  201   a  in  FIG. 9 ), which may be found to provide maximal multi-directional slip resistance. Insert  1  may optionally include elements to correspond to an underside of a toe of an athlete. Preferably, the insert is provided as part of a pair. 
         [0040]    Insert  1  and elements  13  may include an elastomer such as thermoplastic polyurethane (TPU). The elements  13  may be a plurality of discrete elements of one material adhered to a second material providing a main body of the insert, or insert  1  may consist of a single monolithically formed piece of material. In some embodiments, insert  1  has one side that is textured with elements  13  targeted according to a pressure point management system and the other side will be smooth. In certain embodiments, insert  1  is reversible, with high-relief elements on one side and low-relief elements on the other side. 
         [0041]      FIG. 2  gives a cross-section through a shoe insert  1  showing a double-sided embodiment, with high-relief elements  13  on one side and low-relief elements  13  on the other side. High relief elements  13  may protrude from insert  1  by about twice as much as a protrusion of low relief elements (e.g., by about 2 mm and about 1 mm, respectively). Dual-relief insert  1  as pictured in  FIG. 2  gives an athlete an option for controlling an amount of traction and padding provided by elements  13  as well as for fine-tuning comfort provided by insert  1 . Thus, an athlete can use insert  1  to counteract ground-reaction forces that arise during sports performances, and even to exploit and capitalize on ground reaction forces. 
         [0042]    Thus, in some embodiments, insert  1  is reversible. A consumer may place insert  1  in a first orientation to use one side, and then may reverse insert  1  (e.g., into the other shoe) to use the other side. Some athlete&#39;s may find that it is particularly beneficial and desirable to reverse insert sides during a day of activity, as the change in relief or pattern may provide a variable stimulus that prevents fatigue and discomfort. 
         [0043]    In certain embodiments, insert  1  is washable. Insert  1  may be made from a machine-washable polyurethane foam or similarly heat and detergent resilient material. This provides the benefit of allowing insert  1  to simply be put through the washer and dryer (or even through a dishwasher) for cleaning. 
         [0044]    Ground reaction forces and center of pressure patterns have previously been studied. See Williams, RELATIONSHIPS BETWEEN GROUND REACTION FORCES DURING THE GOLF SWING AND ABILITY LEVEL, 1999, Proc. 5th Eng. Sports Mtg., 7 pages. One application of the insights so gleaned involves studying how a shoe interacts with the ground. The interaction of the sole of the foot and the insole of the shoe cannot best be addressed until the interaction of the outsole of the shoe and the ground is understood. 
         [0045]    The physics of momentum transfer from events involving an athlete is dependent on the relationship between the athlete and the ground. The stress and strain relationships between athlete and ground is mediated through a number of surface interfaces: the sole of the foot and the insole of a sock; the outsole of the sock and the top-side of insert  1 ; the bottom-side of insert  1  and the insole of a shoe; the outsole of a sock and the insole of a shoe (if no insert  1  is present); and the outsole of the shoe and the ground. Before turning to phenomenon within the shoe, the relationship between shoe and ground is first addressed. 
         [0046]      FIG. 3  shows a test apparatus  201  for measuring stress between a shoe and ground. Shoe  219  sits on turf  225 . Tray  213  rests on a last inside of shoe  219  via post  231 , all inside of sled  207 . Casters  237  minimize friction between tray  213  and sled  207 . Mass  209  simulates an athlete&#39;s downward force. Ground reaction forces (shear) and center of pressure forces can be measured using a force platform  227 , such as one provided by Kistler (Winterthur, Switzerland). A sport performance, such as a golf stroke, is mimicked by releasing weighted pendulum  241  so that the tip of the pendulum engages a loop on a cable thereby exhibiting a lateral impact force on sled  207 . 
         [0047]    Horizontal (Fy) and vertical (Fz) forces are measured as the force is applied until slip occurs. A traction score, T, is calculated as the peak horizontal force, at the instant a shoe slips, divided by vertical force. 
         [0048]    When a variety of shoes were tested, a baseline Tmin is established using a smooth-sole shoe and is used with a Tmax from the best shoe among the set to calculate a relative traction for the ith shoe based on the traction score Ti for the ith shoe. 
         [0000]      Relative traction (%)=(( Ti−T min)×100/( T max− Ti )  (Eq. 1)
 
         [0049]    In a test of leading brands of golf shoes, a shoe with 6 mm spikes gave Tmax, a Puma Tour gave the next best relative traction (99.7). The poorest, other than the smooth-soled shoe, was 74.2. Accordingly, a first step to minimizing variability or unpredictability of sports performances includes wearing a shoe with a good relative traction score. Once an athlete maximizes the relative traction between shoe and ground, for example, by wearing a Puma Tour shoe for golf, methods of improving performance include optimizing interactions between the shoe and foot. Sports shoes are discussed in U.S. Pat. No. 6,817,117; U.S. Pat. No. 5,987,783; U.S. Pat. No. 5,761,833; and U.S. Pub. 2009/0100718, the contents of each of which are incorporated by reference. 
         [0050]    Having now established a pattern of shoe/ground interaction and, more particularly, a test thereof that can be performed for any shoe, shoe/foot interactions are addressed. Any particular mechanism for affecting shoe/foot interactions may look to force patterns exhibited between the feet and the Earth during a sports performance. 
         [0051]      FIG. 4  shows measured stresses between feet and ground during a golf swing.  FIG. 4  gives a separate graph for the left and the right foot. Along the x-axis (time), start bar  305  indicates a position of a beginning of a downswing. Stroke bar  309  shows a moment of ball impact. In each graph, a box is drawn around a moment of maximum shear force, corresponding to pendulum impact of apparatus  201 . Patterns that appear in  FIG. 4  may be mapped onto the soles of feet or shoes. 
         [0052]      FIG. 5  shows vectors of shear stresses between feet and ground during a golf swing, with each vector originating from a point of maximum vertical force (Fz). The points of maximum vertical force are drawn as small circles that are connected by a broad line that traces the progression of the maximum vertical force during a swing. Studying the vectors shown in  FIG. 3 , it can be understood that a left foot exhibits a maximum shear force in a nearly true heel-to-toe direction at a spot located at the center, forward part of a ball-of-foot region. In contrast, a right foot exhibits a maximum shear force in a direction from inside-toe to outside-heel, on a spot located at the inside, heel-ward part of a ball of the foot. The patterns revealed in  FIG. 5  describe a significant stress phenomenon that a golfer contends with while making a shot. 
         [0053]    Even with the best shoe (e.g., a Puma Tour), a golfer&#39;s foot will be pushed, relative to the insole of the shoe, according to the pattern of shear force vectors and center of pressure locations described in  FIG. 3 . Given that it is not a known practice to directly functionalize the human foot with cleats, it is an objective of the invention to functionalize the human foot with traction elements that resist the pattern shown. 
         [0054]    An insight of the invention is that, while socks participate in two of the three body/ground interface surfaces, the fabric of socks can be exploited to attenuate body/ground slippage associated with shear forces as well as, simultaneously, discomfort associated with compressive forces. A footwear system with direct contact between elements on the outsole of a sock and an insole of a shoe may provide traction at both the interface between the sock outsole and shoe insole and the interface between the foot and the sock insole (e.g., due to the fabric pliability of the sock). Accordingly, the invention provides footwear systems, including individual socks, with one or more elements on the outsoles of socks that have an arrangement corresponding to a location of one or more of a maximum stress between a foot and the ground during a sports performance. In some embodiments, systems and articles of the invention will include at least one sock. 
         [0055]      FIG. 6  illustrates a sock  101  of embodiments of the invention. Sock  101  generally includes a cuff  107  at a terminus of leg portion  111 . Leg portion  111  extends to instep  119 , which terminates at toe region  123 . Leg portion  111  also extends to heel flap  131 . A sock sole  137  generally extends between heel flap  131 , edges of instep  119 , and toe  123 . While sock  101  in  FIG. 6  is drawn with lines appearing to set off heel flap  131 , cuff  107 , and toe  123 , these portions of a sock need not be of separate material or separate pieces of material than the other parts of sock  101 , and they need not correspond in size or shape to those areas shown in  FIG. 4 . 
         [0056]    Sock  101  can be made from any suitable material and by any suitable method. Sock  101  can be manufactured by a machine, such as an industrial fabricator or a home knitting machine. Sock  101  may be made by sewing pieces of fabric together. In certain embodiments, sock  101  is knit using a circular knitting machine. The machine uses needles on a cylinder or double cylinder. As the cylinder rotates, the needles knit the yarn, creating a tube of sock with an open toe, which is then closed. A separate toe piece can be sewn on, or the toe can be sewn closed. The socks are optionally dyed or decorated or shaped on fiberboard forms. 
         [0057]    In some embodiments, socks are obtained in which a fabric portion is pre-made substantially as shown in  FIG. 6  or  FIG. 7  and further functionalized according to methods of the invention. Methods for making socks are provided in U.S. Pat. No. 7,878,029; U.S. Pat. No. 7,047,767; U.S. Pat. No. 6,289,701; and U.S. Pub. 2012/0024014, the contents of which are incorporated by reference for all purposes. 
         [0058]    A sock of the invention can be any suitable size, style, or material. Socks can be made of cotton, wool, acrylic, or any other natural or synthetic fiber. Socks can include nylon, polyester, rayon, or a combination of any of these materials. Socks can be foot-shaped or tube socks, and can have any thickness of material, overall length, or other dimensions. A sock can include a gusset at the area where heel flap, leg, and instep come together. Socks may extend above the knee, or at least cover the ankle, or not. 
         [0059]      FIG. 7  depicts a socklet according to embodiments. A socklet is typically a sock that does not extend above the ankle. Some golfers may prefer a socklet for the stress-attenuation benefits of the invention while simultaneously having maximum exposure to outdoor air (e.g., on a hot day). Regardless of the length of a sock, the invention provides functionalization of a sole  137  of the sock. The invention includes the insight that different regions of a sole of a sock, as well as corresponding regions of an insole of a shoe, may each play a different role in the performance of a golfer&#39;s shot. 
         [0060]      FIG. 8  is a diagram of regions of a sole  137 . Sole  137  includes an inside toe region  141  and an outside toe region  146  just forward of a ball-of-foot region  151 . There is an inside ball-of-foot region  169  disposed alongside an outside ball-of-foot region  157 , as there is an inside mid-foot region  167  disposed along an outside mid-foot region  161 . Distal to the toe area is a heel region  165 . 
         [0061]    The dashed lines in  FIG. 8  do not necessarily show precise boundaries. A region is just an area of a sock, and one region may be deemed to overlap or extend into another. Any arbitrary area on a sock may be said to lie within a region if it overlaps that region and may be said to lie substantially within a region if a substantial portion of the area lies within the region. A region&#39;s boundary need not be thought of as a single clearly defined line, but may be understood more generally to be a transition zone. In certain embodiments, a sole  137  of a sock  101  is functionalized by the provision of a cushioning or traction element, which may be referred to as a padding element. 
         [0062]    The invention provides socks and footwear systems in which a sole of a sock includes a padding element. A padding element is an element on a sole of a sock that affects the interplay between the foot and the insole of a shoe. Padding can mean cushioning, in one of its familiar senses. However, padding can be taken to have meanings that include the provision of displacement, as from a shim, or the provision of a foundation or support (e.g., analogous to the pouring of a concrete pad in construction). Padding may be taken to mean the provision of shape (e.g., as in a shoulder pad in a jacket), the provision of a feature for human contact (e.g., as in a keypad), the provision of a material for compressive impact or energy displacement (e.g., as in a drum pad), or a combination of any of the foregoing. For example, a pad may comprise a plurality of hard plastic areas, as does a keypad. In some embodiments, a pad includes or consists of a foam material (e.g., foam rubber) or an area in which a fabric is provided more thickly than in surrounding areas. In certain embodiments, a pad includes one or a plurality of areas of a polymer on the fabric of a sock. Pads can include one or more of a rubber, fabric, polymer, plastic, leather, wax, thread, fiber, paper, cardboard, or other material, in any combination. 
         [0063]    A pad (e.g., polymer) may be infused into, or adhered onto, the fabric of a sock. A polymer may be so affixed only by its own material properties, or through the use of an adhesive or stitching. A polymer may be attached to fabric by any suitable method including gluing, stitching, printing, molding, melting, fusing, others, or a combination thereof. Any suitable polymer may be used including, for example, a polyurethane such as thermoplastic polyurethane. Methods of adding pads are discussed in U.S. Pat. No. 6,708,342; U.S. Pub. 2011/00233215; U.S. Pub. 2007/0204482; U.S. Pub. 2007/0028365; and U.S. Pub. 2005/0241186, the contents of which are incorporated by reference for all purposes. In general, at least one padding element will typically be included in sole  137  disposed, for example, at or near a location of maximal stress during a golf swing. 
         [0064]      FIG. 9  depicts sole  137  of sock  101  according to certain embodiments of the invention. Sole  137  is shown here including ten of padding element  201   a ,  201   b , . . . ,  201   n . Each padding element  201  includes 18 spots of polymer affixed to sole  137 . The 18 spots of an element  201  are disposed in a substantially hexagonal array. It may be found that the use of 18 sub-elements makes for an optimal pattern for traction control by providing an excellent coefficient of static friction in many lateral directions—better even than other simpler geometric patterns. Where a padding element  201  includes a shape, a polygon, circle or ellipse, or irregular shape may be used. In some embodiments, a polygon is included due to, for example, the ability to provide edges that oppose the shear force. An edge of padding element  201  may provide particular traction in a direction perpendicular to an edge. A direction of traction may be viewed as a vector, with components in directions other than the vector. For any shear force, two non-parallel edges of a polygon will provide at least one component of a vector of traction that is antiparallel to the vector of shear force. In some embodiments, the strongest traction vector is associated with the edge most nearly perpendicular to the shear force vector. For a series of shear forces oriented in different directions, or for one shear force that will be oriented in an unpredictable direction, the more sides a polygon has, the greater probability that it will present at least one edge at less than some arbitrary maximum deviation from the direction perpendicular to the shear force(s). Accordingly, hexagons may generally provide more traction than pentagons and squares, etc. Note that in alternative embodiments, maximum traction may not be associated with an edge of a polygon, but may be associated with a material of element  201 , and amount of vertical relief, a material of an insole of a shoe, other factors, or a combination thereof. 
         [0065]    Where element  201  has a shape of a polygon, it may be preferred to use a polygon or combination of polygons that tessellate or exhibit efficient packing. Packing of polygons may be taken to mean a ratio of area enclosed by a polygon to a ratio of total area when a pattern of polygons is arranged to maximize that ratio. Efficient packing may then refer to the minimizing of interstitial “space” between polygons. Fully tessellating regular polygons include isosceles triangles, rectangles, and hexagons. In some embodiments, a hexagon is used to have a fully tessellating form with edges in a desired number of directions. In alternative embodiments, it may be desired to optimize an edge to area ratio (e.g., to maximize it), and another form (e.g., isosceles triangle or square) may be used. Furthermore, a particular shape (e.g., such as a given overall shape) may be desired to optimize an aspect of a manufacturing process. For example, where elements  201  are manufactured separately from sock  201  and then adhered thereto, elements  201  may be manufactured in a sheet form, for example, as a material adhered to a paper substrate. Accordingly, it may be desired to use a shape with arbitrarily high packing efficiency or tessellation to minimize waste of the sheet. As shown in  FIG. 7 , elements  201  have a hexagonal overall shape, and are presented in three different sizes. Other patterns are within the scope of the invention. It will be noted that sole  137  depicted in  FIG. 9  appears as the sole of one foot. A sock  101  of the invention may be provided as a pair, and in some embodiments, the pair of socks has a symmetrical pattern of elements  201  (one sock is the minor image of the other). In certain embodiments, a pattern of elements  201  on the soles  137  of a pair of socks in asymmetrical. In other embodiments, only one sock of a pair has elements  101 . Any exemplary sock herein may be taken to show a pair where the other sock may be the symmetrical match to the depicted sock. Additionally, any two socks depicted herein may be taken to form a pair. In some embodiments, the invention provides a pair of socks in which one sock has one of the patterns shown or discussed herein, or a variant thereof, and the other sock as a related but non-matching pattern, such as the inclusion of at least one matching element but in a non-corresponding location. 
         [0066]      FIG. 10  shows a sole  137  that is similar to the sole shown in  FIG. 9  but without elements  201  disposed at the toe area. It can be noted in  FIGS. 7 and 8  that elements  201  are presented in at least three different sizes. The medium size is shown at interior ball-of-foot region  169 , an element of large size is shown at heel region  165 , and at least one small element  201  is depicted in outside mid-foot region  161 . In some embodiments, this pattern is preferable as a heel needs a large element  201  for comfort and weight distribution while interior ball-of-foot region  169  needs a compact but substantially effective element  201 . An outside mid-foot region  161  is an optional location for an element  201 . 
         [0067]      FIG. 11  illustrates a sole  137  that includes irregularly-shaped elements  201 . Here, the shape, size, and thickness (including optionally variations in thickness) of elements  201  are shown provided in a fashion that can correspond with great precision to regions of maximal stress. 
         [0068]      FIGS. 10 and 11  show exemplary socks according to the invention. Sock  101  can include features known in socks, such as toe, heel flap, or both being provided in another material or color. Socks  101  can include printed information, for example, relating to the benefits of elements  201 . Printed information can provide a significant utilitarian benefit. One or more indicia printed on a sock can direct a golfer in proper use of the footwear system. By using graphics, text, layout, or a combination thereof, to communicate the benefits of the elements for padding and traction, provide information concerning proper use, or both, printed indicia may enhance a golfer&#39;s benefit from use of the invention. Useful printed indicia can include indications of locations of elements  201 , information about a corresponding insole, sock size or foot (e.g., L v R), a wear indicator, or simply a brand name or statement of the function of the sock or footwear system. 
         [0069]    As shown in  FIGS. 10 and 11 , elements  201  may have an overall shape (here, square) of one material, with additional features therein or thereon. Here, each square of element  201  includes a hexagonal pattern of spots of material. This may be preferred where, for example, sock  101  and element  201  are manufactured separately and then elements  201  are affixed to sock  101 . Other shapes and patterns of elements  201  are provided. 
         [0070]      FIG. 14  shows a pair of socks in which elements  201  are provided as localized regions of gripping dots including a material such as TPU. 
         [0071]    In certain aspects, the invention provides a footwear system in which a sock  101  has an element  201  on a sole of the sock and the system further includes an insole of a shoe with a feature in a corresponding location. While useful in any sport, golf provides an excellent illustrative example. Such a system provides the particular benefit of locking a golfer&#39;s foot to the foot-bed of their shoe. When used in conjunction with a shoe that scores acceptably on the stress test described above, excellent locking between a golfer&#39;s foot and the ground is achieved. Accordingly, the invention provides methods of improving one&#39;s performance by using a sock with a padding element and a shoe with an insole with an interacting feature in a corresponding location. The elements on the sock and on the insole of the shoe interact for maximum comfort, grip, or both. Systems of the invention can include shoes that have features corresponding to the elements  201  on sole  137  of sock  101 . In certain embodiments, the invention provides insoles for shoes wherein the insoles have the features. Thus an athlete may procure functionalized shoes and socks, or functionalized insoles and socks, and insert the insoles into their golf shoes to obtain the benefits of the invention. Insoles may optionally include a mechanism for fixing them into the foot-bed of shoes such as, for example, an adhesive backing. 
         [0072]    By providing insoles that interact with socks  101 , systems and methods of the invention optimize an athlete&#39;s performance. The features on the insoles of the shoes can have a profile that complements elements  201  on socks  101 . For example, elements  201  can be gripping dots, and the insoles can have pockets. In some embodiments, elements  201  are textured areas for high friction and the insoles feature complementary textured areas or rubber areas. 
         [0073]      FIG. 15  shows a pair of socks  101  in which elements  201  are included having a linear pattern. Each element  201  may be provided with a series of ridges and valleys, which can be straight (as shown in  FIG. 13 ), sinuous, curved, zigzag, irregular, etc. In some aspects, 
         [0074]    In certain embodiments, elements  201  include ridge-and-valley structures and the insoles are provided with corresponding ridge-and-valley structures. When the ridge-and-valley elements  201  of socks  101  mate with the structured insoles, shear motion perpendicular to the ridgelines is prevented. Moreover, by providing a padding element of a deformable material (e.g., polyurethane), a cushioning aspect is provided. 
         [0075]    In certain embodiments, a padding element  201  (e.g., as shown in  FIG. 13 ) may have a ridge-line or edge that is substantially perpendicular to vector of maximum shear stress (e.g., as shown in  FIG. 3 ). A sole  137  may include a plurality of such elements  201 , in which each element includes an edge or contour that is substantially perpendicular to a corresponding vector. In some embodiments, each dot (e.g., at the origin of each vector) shown in  FIG. 5  corresponds substantially to a geometric center of gravity of an element  201  on a sole  137  of a sock  101 , and each element  201  has a linear component oriented normal to the corresponding vector. The invention also includes footwear systems in which an insole of a shoe includes features with linear elements that correspond to, and interlock with, elements  201 . 
         [0076]    According, in some embodiments,  FIG. 15  shows elements  201  having ridge-and-valley structures. The invention also provides insoles with corresponding structures. The ridges may be oriented so that ridgelines run substantially perpendicular to a vector of maximal shear stress. A sole  137  may include a large element  201 , for example, at the ball-of-foot region. To supplement the shear resistance of the ridgelines, sole  137  may include other elements  201  having ridgelines that run in other directions, as shown in  FIG. 13 . While depicted in  FIG. 15  as being approximately symmetric, a pattern of elements need not be. In fact, in some embodiments, only one sock of a pair includes one or more of element  201 . 
         [0077]      FIG. 16  displays an exemplary pair of socks  101  in which only one sock includes elements  201 . Here, element  201  is depicted as a pattern of ten triangles. Where only one sock include element  201 , it may be either sock of a pair. A golfer may prefer element  201  on a dominant foot. 
         [0078]    An element  201  as depicted in any figure herein, or as discussed herein, may include an amount of relief. Relief, generally, is a measure of an amount of thickness added to fabric by virtue of a thickness of element  201 . An element  201  may have 0 (zero) relief by being printed substantially smoothly on the fabric (as type is typically printed on a page). An element  201  may have uniform relief, indicating a generally planar surface with a contour that mimics the contour of a surface of sock  101  (and therefore a contour of a foot). An element  201  may have varying relief, such as is provided by a rippled, textured, sloped, beveled, or contoured surface. An amount of relief at any given point may be zero, or it may be between 0.001 mm and 1 cm. In certain embodiments, an amount of relief is between about 0.5 mm and about 3 mm (e.g., between about 0.7 mm and about 1.5 mm). 
         [0079]      FIG. 17  shows a pair of socks  101  according to certain embodiments in which element  201  is a hexagonal ring with a vacant area in the middle of about a quarter of the area of the overall hexagon. While depicted here as only being on sock, a pair of socks may be provided in which both include element  201 . A location or distribution of elements may be determined with reference to information about ground stresses on a golfer. 
         [0080]    The invention includes methods of making socks for improved golfing by using information about ground stress. Ground stress information may be had by performing tests on a golfer, or by reference to available information. In the context of footwear systems of the invention, a pattern of ground stress information may be used as a template for making socks. Methods of the invention include receiving a template that shows a pattern corresponding to regions of maximal stress experienced on the sole of a golfer&#39;s foot during a golf swing and adding padding elements  201  to the sole of a fabric sock  101  according to the pattern. 
         [0081]      FIG. 18  is a reproduction of results of measuring sole stress during a golf swing. The results depicted in  FIG. 18  were originally presented in color. For the purposes of preparing a template for making socks, color data may be reformatted as black and white. 
         [0082]      FIG. 19  is a contour diagram of regions of stress shown in  FIG. 16 . As shown in  FIG. 17 , black regions correspond to what were red regions of the display shown in  FIG. 16 . White areas immediately adjacent to the black areas correspond to, and may be pictured as, orange. Gray zones (in  FIG. 17 ) were depicted as yellow zones in  FIG. 18  and the outer white zones may be pictured as green. Striped zones correspond to blue zones. In this manner, the color spectrum in  FIG. 18  that stood for a measure of stress intensity can processed as specific areas. Any suitable image processing operation may be used. In certain embodiments, a morphological processing operation—such as erosion, dilation, others, or a combination thereof—may be used to prepare a template such as the one depicted in  FIG. 17 . Known computer programs can generate color separations. See, for example, Markham, CMYK COLOR SEPARATIONS USING THE GIMP, accessed on Nov. 1, 2011, from the web site Alternative Photography. One benefit of a template such as  FIG. 19  or a color separation of data such as that shown in  FIG. 18  (noting that a color separation is, by nature, a black and white image) is that it itself may be used as camera-ready art in the preparation of silk screens for printing TPU elements onto socks. That is, in certain embodiments, the template dictates the positioning of elements  201  on socks  101 . In some embodiments, such a template is used to determine where to locate elements  201  on socks  101 . A template can be any information that relates areas of stress during a golfer&#39;s swing and can have any suitable format. For example, a template may consist of numerical coordinates indicating locations on soles and values that indicate stress by magnitude, vector, or both. 
         [0083]      FIG. 20  diagrams a method of improving a golfer&#39;s game. Steps of methods of the invention can be performed in any suitable order.  FIG. 20  provides but one exemplary diagram. A template, as discussed above, is obtained along with any parameters relating to footwear. For example, where socks are to be manufactured, an order of socks and parameters relating to color, decoration, size, etc., may be received. Where a footwear system (e.g., a single custom system for a golfer) is to provided, information about a preferred shoe may be received. 
         [0084]    Obtaining a template may include using a fitting system to obtain stress data points that are then transferred to a computer for processing. A fitting system may include a device for measuring stresses, an area set up like a sports-playing area (e.g., a golfing tee-off area, a baseball batting diamond, a square of basketball court with net, a race car simulator with seat and pedals, etc.) A fitting system may be provided by a store or similar enterprise (such as a university athletic department or a pro sports league training gym). A portable fitting system may be taken to, and used at, events such as a PGA show. A fitting system may be an installation in a sports pro shop, such as a golf pro shop. A fitting system may be a kiosk with a measuring platform (e.g., a frame with a metal and/or rubberized pad that measures stress via sensors such as a scale or magnetic shear measurements) that measures stress and transmits the measurements to a computer in the kiosk for use in a template of the athlete&#39;s stress patterns. Foot mapping kiosks are described in U.S. Pub. 2012/0191554 and U.S. Pat. No. 8,117,922. A kiosk may be used in a store or at a show or public event to measure properties associated with an athlete&#39;s foot and to provide the template. 
         [0085]    Footwear is then prepared. This can include making socks and/or mounting them on some suitable frame. Elements  201  are then added to the socks. In certain embodiments, this involves screen printing TPU onto sock fabric. Any required details (e.g., cuff-stitching, printing of size information, monogramming) are added. In contexts that involve customization or personalization, relevant details are prepared. For example, a golfer may provide a personalized template for locations of elements  201 . In some embodiments, a golfer is given choice of different styles of elements  201 . In embodiments in which a footwear system is being provided, an insole is provided, either as part of a shoe, or for inserting into a shoe. Once the sock and optional insole is prepared it is delivered. For example, a shipment of socks can be delivered to a truck, to be carried to a distribution center. Or a customer&#39;s online order can be shipped to their home. 
         [0086]      FIG. 21  shows an exemplary system for improving a golfer&#39;s game. In some aspects, the invention provides a system for making a sock that provides the ability to receive a template that shows a pattern corresponding to regions of maximal stress (e.g.,  FIG. 3 ,  FIG. 8 ,  FIG. 9 ,  FIG. 17 , etc.) and to coordinate operations for adding elements for padding and traction to a sock according to the pattern. 
         [0087]      FIG. 21  shows components in an exemplary system for producing footwear systems. As shown in  FIG. 19 , system  400  generally includes one or more computer, communicably coupled via network  415 . Systems and methods of the invention may generally be implemented through the use of one or more computer such as any combination of a provider computer  481 , a production computer  461 , and a consumer computer  401  along with, for example, a sales server  441  and a production server  421 . A computer generally includes a processor (e.g.,  409 ,  489 ,  469 ,  449 ,  429 ) operably coupled to a memory (e.g.,  407 ,  487 ,  467 ,  447 ,  427 ) and configured to send or receive information via input-output device (e.g.,  405 ,  485 ,  465 ,  445 ,  425 ). 
         [0088]    One of skill in the art will recognize that a processor may be provided by one or more processors including, for example, one or more of a single core or multi-core processor (e.g., AMD Phenom II X2, Intel Core Duo, AMD Phenom II X4, Intel Core i5, Intel Core i&amp; Extreme Edition 980X, or Intel Xeon E7-2820). In certain embodiments, any of consumer computer  401 , provider computer  481 , production computer  461  may be a notebook or desktop computer sold by Apple (Cupertino, Calif.) or a desktop, laptop, or similar PC-compatible computer such as a Dell Latitude E6520 PC laptop available from Dell Inc. (Round Rock, Tex.). Such a computer will typically include a suitable operating system such as, for example, Windows 7, Windows 8, Windows XP, all from Microsoft (Redmond, Wash.), OS X from Apple (Cupertino, Calif.), or Ubuntu Linux from Canonical Group Limited (London, UK). In some embodiments, any of consumer computer  401 , provider computer  481 , production computer  461  may be a tablet or smart-phone form factor device and processor  481  can be provided by, for example, an ARM-based system-on-a-chip (SoC) processor such as the 1.2 GHz dual-core Exynos SoC processor from Samsung Electronics (Samsung Town, Seoul, South Korea). 
         [0089]    In some embodiments, either of sales server  441  or production server  421  can be a Hitachi Compute Blade  500  computer device sold by Hitachi Data Systems (Santa Clara, Calif.). Either of processor  449  or processor  429  can be, for example, a E5-2600 processor sold under the trademark Xeon by Intel Corporation (Santa Clara, Calif.). 
         [0090]    Input-output devices generally includes one or a combination of monitor, keyboard, mouse, data jack (e.g., Ethernet port, modem jack, HDMI port, mini-HDMI port, USB port), Wi-Fi card, touchscreen (e.g., CRT, LCD, LED, AMOLED, Super AMOLED), pointing device, trackpad, microphone, speaker, light (e.g., LED), or light/image projection device. 
         [0091]    In certain embodiments, a template is received via a consumer&#39;s use of consumer computer  401  or via a designer&#39;s use of provider computer  481  and the selection is received at sales server  441  and stored in memory  447 . Sales server  441  may use a network card for input/output  445  to received data. Sales server  441  may provide an order database  443  which may include accounts  444  where consumer information is stored (e.g., for payment and delivery information). 
         [0092]    After orders are received and ready for production, one or more templates, other order information, or a combination thereof can be transferred via input/output  445  from sales server  441  to production server  421  via input/output  425 , which may also be a network card or other data transfer mechanism. Order information (e.g., orders  439 ) is stored in production database  435  in memory  427 . Processor  429  executes computer program instructions stored in memory  427  to initiate production. 
         [0093]    A production facility may be equipped with a production computer  461  which either automatically coordinates the operation of machines or provides information to production employees, e.g., via input/output  465 , which could include, for example, a monitor or laser printer. 
         [0094]    Many of the steps and functions described herein can be planned or coordinated by a provider personnel using provider computer  481 . For example, engineers or sales personnel can prepare and upload information (e.g., one or more template, digital files such as in a comma-separated values (CSV) format). That is, in certain embodiments, provider personnel use provider computer  481  to design or plan production of particular socks or footwear systems. 
         [0095]    A memory generally refers to one or more storage devices for storing data or carrying information, e.g., semiconductor, magnetic, magneto-optical disks, or optical disks. In certain embodiments, a storage device of the invention includes a tangible, non-transitory computer readable medium for memory. Exemplary devices for use as memory include semiconductor memory devices, (e.g., EPROM, EEPROM, solid state drive (SSD), and flash memory devices e.g., SD, micro SD, SDXC, SDIO, SDHC cards); magnetic disks, (e.g., internal hard disks or removable disks); magneto-optical disks; and optical disks (e.g., CD and DVD disks). The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
         [0096]    Footwear systems and articles of the invention may be made with reference to particular portions of a sole of a foot, sock, or insole.  FIG. 8  displayed regions of a sole. In some embodiments, elements or features are located on a sole with more particular reference to detailed specific regions of a sole. 
         [0097]      FIG. 22  is a detailed diagram of specific regions of a sole  137 . Sole  137  includes an inside toe region  141  and an outside toe region  145  just forward of a ball-of-foot region  151 . A shared central toe portion  177  occupies parts of inside toe region  141  and outside toe region  145 . There is an inside ball-of-foot region  169  disposed alongside an outside ball-of-foot region  157 , both in connection with fore-central ball-of-foot region  175 . There is an outer-edge ball-of-foot region  153 . Sole  137  further includes an inside mid-foot region  167  disposed along an outside mid-foot region  161 . Outside mid-foot region  161  is lead by forward outside mid-foot area  159  and trailed by trailing outside mid-foot area  163 . Heel region  165  is lead by forward heel region  155  and trailed by trailing heel region  173 . In certain embodiments, a sock  101  or insole of the invention comprises an element  201  or feature, respectively, substantially or essentially contiguous with central toe portion  177 , fore-central ball-of-foot region  175 , forward outside mid-foot area  159 , forward heel region  155 , or a combination thereof. In some embodiments, a sock  101  or insole of the invention comprises an element  201  or feature, respectively, substantially or essentially contiguous with central toe portion  177 , fore-central ball-of-foot region  175 , forward outside mid-foot area  159 , and forward heel region  155 , as depicted in  FIG. 20 , as this may provide enhanced benefits of improved golfing according to insights of the invention. 
         [0098]    In certain embodiments, a pair of socks of the invention includes elements  201  at locations corresponding to the origins of one or more of the vectors depicted in  FIG. 3 . For example—making reference to  FIG. 20 , and imaging its minor image to visualize both a left and a right sock  101 —in some embodiments, a right sock includes an element  201  at each of inside ball-of-foot region  169 , fore-central ball-of-foot region  175 , and outside ball-of-foot region  157 , or a continuous element  201  across a corresponding area (optionally including element  201  at outer-edge ball-of-foot region  153  for additional lateral support benefit). A left sock includes an element  201  at each of fore-central ball-of-foot region  175 , outside ball-of-foot region  157 , and forward outside mid-foot area  159 , or a continuous element  201  disposed across a corresponding area. In certain alternative embodiments, the left and the right sock are substantially symmetric to one another to offer a benefit to consumers of matched feel for certain consumer who may find asymmetric socks a distraction. In some embodiments, the invention provides insoles with corresponding features. The features and elements may be designed to provide a high degree of traction to resist lateral displacement that would result from unmitigated shear stresses. Displacement-resistance can be provided by a textured surface, a pliable material (e.g., TPU), ridgelines or contours, edges, corresponding protrusions and divots, gripping balls, nubbins, or combinations thereof. Additionally, in some embodiments, one or more of element  201  may wrap from the sole, outwards and upwards, extending to the sides of sock  101  (e.g., towards the instep  119 ) for the benefit of additional tactile feedback. While discussed above in terms generally of traction and cushioning (e.g., to offset stresses and prevent fatigue, which reduces subconscious foot positioning), additional benefits include tactile feedback. The inclusion of one or more of element  201  give stimulus points by which a golfer may understand the positioning of the foot in relationship to the shoe and the ground, thereby aiding a golfer in continually improving their athletic ability. 
         [0099]    As used herein, the word “or” means “and or or”, sometimes seen or referred to as “and/or”, unless indicated otherwise. 
       INCORPORATION BY REFERENCE 
       [0100]    References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
       EQUIVALENTS 
       [0101]    Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.