Abstract: In an aspect there is provided a swing scooter, comprising a frame, a steering member, a front wheel, at least two support legs, and at least two platforms. A rear wheel support is pivotally attached each support leg. A rear wheel is rotatably attached to each rear wheel support. Each platform is movably attached to an associated support leg, and positioned for supporting a foot of a user. Each platform has a longitudinal platform axis and is movable between a first position in which the platform is angled down laterally towards a first lateral side of the swing scooter, and a second position in which the platform is angled down laterally towards a second lateral side of the swing scooter. The platform is movable to the first and second positions by movement of the foot of the user.

Abstract: A system, method, and apparatus for replicating the experience of snow skiing on dry land using a roller land ski with an ability to move and stop consistent with mechanics of an actual snow ski. Each land ski includes a rigid platform with a binding for engagement with a specialized boot, a pair of biased omnidirectional casters supporting said rigid platform, but mounted to a top surface of said platform, and a pair of trucks with a plurality of wheels along its curved axles. A pair of specialized boots constructed out of flexible lightweight material with a stiff support structure to fortify a user's foot and ankle from the forces created by the land ski are included in this system. The method includes calibration and selection of materials for both the board and boot in order to achieve the desired experience.

Abstract: Provided herein is a training device configured to allow a user to simulate all of the balancing and turning movements of downhill snow skiing or snowboarding on dry, downhill surfaces. The device is equipped with a braking system that allows the user to slow down the speed of travel when the moving direction changes from forward to sideways, thereby simulating the act of slowing down on a slope by turning a ski or snowboard. The braking effect is further enhanced when the ski or snowboard is tilted towards the uphill direction, further simulating the actual movements of skiing or snowboarding on snow. The braking system may include one or more mechanisms to amplify the force applied to the brake cables. An optional steering bar may be provided with handles that are positioned ahead of the bar to simulate the planting of ski poles prior to or during a turn.

Abstract: Provided herein is a training device configured to allow a user to simulate all of the balancing and turning movements of downhill snow skiing or snowboarding on dry, downhill surfaces. The device is equipped with a braking system that allows the user to slow down the speed of travel when the moving direction changes from forward to sideways, thereby simulating the act of slowing down on a slope by turning a ski or snowboard. The braking effect is further enhanced when the ski or snowboard is tilted towards the uphill direction, further simulating the actual movements of skiing or snowboarding on snow. The braking system may include one or more mechanisms to amplify the force applied to the brake cables. An optional steering bar may be provided with handles that are positioned ahead of the bar to simulate the planting of ski poles prior to or during a turn.

Abstract: A wheeled ski is disclosed that may include a flexible member. The wheeled ski may also include a first wheel assembly that includes a first wheel with a first-wheel first rotational axis and a first-wheel second rotational axis. The first-wheel first rotational axis and the second-wheel second rotational axis may intersect. The wheeled ski may also include a second wheel assembly that includes a second wheel with a second-wheel first rotational axis and a second-wheel second rotational axis. The second-wheel first rotational axis and the second-wheel second rotational axis may intersect. The first wheel assembly may further include a first axle coupled with the flexible member and a first rod that extends through the first axle. The second wheel assembly may further include a second axle coupled with the flexible member and a second rod that extends through the second axle.

Abstract: A side-by-side pair of platforms, each equipped with a foot-pad, are coupled in a manner to form a vehicle, and are supported (a) at the rear by a truck-mount under each platform, integrated with a shared axle assembly fitted at its ends with a pair of rear wheels, located at opposite sides of the vehicle, and (b) at the front by a tilt-turn mount system including at least one front wheel, typically a caster-mounted roller, accomplishing dual-platform tilt-turning in response to the user's body movements simulating superior snow-skiing techniques, thus enabling sustained self-propulsion by user body movements and providing recreation, training and practice for skiers of all ages and skill levels.

Abstract: Improved skateboards and methods of obtaining or providing skateboards with improved trucks. Trucks have two axles or axes, two primary wheels, and two secondary wheels, and skateboards have eight wheels, four in front and four at the rear portion of the skateboard. The four primary wheels support most or all of the weight of the skateboard when the skateboard is on a flat surface, and the two secondary wheels support the weight of one portion of the skateboard (e.g., front or rear) when the primary wheels cross a crack (e.g., a sidewalk contraction joint). In various embodiments, the secondary wheels are located outboard of the primary wheels. Further, in a number of embodiments, the axis of rotation or axle of the primary wheels remains parallel to that of the secondary wheels, whether the skateboard is going straight or turning.

Abstract: A skateboard, comprising a platform, a rear truck coupled to the platform, and a pair of front casters being coupled to the platform. The skateboard front casters are frictionally coupled with an elastomeric band, thereby frictionally keeping the front casters in alignment.

Abstract: A kicktail concave skateboard includes a blank having opposite ends, at least one end being recessed. An element is mounted on the recessed end such that a portion of the element adjoining the blank is flush with the blank. The element is formed of a material having a lower mechanical damping capacity and a higher modulus of elasticity than the blank. The element includes a downwardly facing exposed side having a downward projection thereon, to facilitate the execution of an “ollie” maneuver.

Abstract: The invention relates to a roller ski having a suspension system incorporated into the front and rear regions of the main roller ski body. The suspension system allows roller-skiers to undertake roller-skiing on rougher pavement, asphalt or the like by reducing stress and/or discomfort to the roller-skier. In addition, the suspension system provides a skiing experience that more closely resembles skiing on snow by returning energy back to the skier in a manner similar to the effect that the camber of a snow ski provides to the skier. In addition, in one embodiment, the roller ski also includes a pressure sensitive ratchet system that simulates skiing using classical technique.

Abstract: A wheeled sport apparatus may comprise a platform and first and second sets of wheels disposed on the platform. Each set of wheels may include a center wheel between two outboard wheels and the outboard wheels may be toed outward for defining a turning radius. One or more carrier wheels may be provided between the first and second sets of wheels.

Abstract: The invention relates to a roller ski which is employed amongst other things for training in classic cross-country skiing during the summer. The object of this roller ski is to achieve a pressure-dependent grip when a kick is generated, with the result that more pressure on the ski from the foot provides better grip. This is in order to simulate skiing on snow, where in classic style pressure has to be placed on the ski during the kick in order to obtain grip on the middle of the ski. The invention is based on a common principle. Roller systems with free roll both forwards and backwards are combined with roller systems with one-way roll, in such a manner that when the pressure on the roller ski from the skier increases, the roller system(s) with one-way roll will be activated to an increasing extent as the pressure on the ski increases, with the result that the ski obtains grip thereby enabling a kick to be generated.

Abstract: A wheeled riding device has a body with an elongate front arm, a turning tail, and a joint part pivotally connecting the turning tail and front arm relative to one another. A front wheel is carried by a forward end of the front arm. Rear wheels are carried by a rear end of the turning tail. A standing platform is supported over the front arm and turning tail. The rear wheels and turning tail can pivot laterally side to side relative to the front arm. The front wheel and front arm can pivot vertically up and down relative to the standing platform. The front wheel, during a turn, is cambered inward into the turn. The device is controlled by the rider using body movements and skills required to ride a snowboard.

Abstract: A wheeled sport apparatus may comprise a platform and first and second sets of wheels disposed on the platform. Each set of wheels may include a center wheel between two outboard wheels and the outboard wheels may be toed outward for defining a turning radius. One or more carrier wheels may be provided between the first and second sets of wheels.

Abstract: The present invention relates to a roller ski or board, said ski or board providing in-line central rollers, centrally provided on the ski or board body, and two pairs of additional rollers, respectively a front pair and a rear pair, said pair of rollers being raised with respect to the ground on which ski or board rests when the same ski or board is substantially parallel with respect to the ground, and contacting the same ground when ski or board is inclined, each one of the additional rollers is coupled with the ski or board by a support system comprising a fork, having one end coupled with the roller and the other one faced toward the ski or board, between the end of the fork faced toward the ski or board and the same ski or board being provided with a resilient element.

Abstract: A roller ski allowing the skier to slide laterally in a manner similar to a snow ski. The system includes at least one ski and it would attach one foot per ski. Each ski has an optionally height and longitudinal angularly adjustable center platform for fixturing the skier's foot with an optionally releasable ski binding system, an optionally height and longitudinal angularly adjustable front tip and rear tail for attaching at least four fixed wheels, and at least two biased pivoting casters which are all positioned along the center platform's longitudinal axis. The fixed wheels function similarly to conventional roller skate trucks. The casters rotate to align themselves with the direction of force exerted on the center platform. The casters are spring biased to align them selves with the longitudinal axis of the center platform.

Abstract: A pair of roller skis each comprising at least four fixed rollers disposed in parallel on the central lower face of a long and narrow board made of an elastic material while having a left-right spacing corresponding to the width of the board and while having a front-rear spacing shorter than the front-rear length of a boot secured to the board, and two casters, one disposed on the lower face of the top portion of the board and the other disposed on the lower face of the tail portion of the board, wherein when the board is placed on the ground with no load applied thereto, only the rollers of the top and tail casters make contact with the ground and the fixed rollers at the central portion are away from the ground. With this configuration, it is possible for the user to enjoy or practice skiing on slopes with no snow while having sliding feelings and using sliding techniques similar to those of snow skiing.

Abstract: A footboard for play, exercise and practice of aerial maneuvers and recreational moves on a jumping device. The footboard is preferably flexible in a variety of directions, but has sufficient firmness so as to allow the board to retain a desired shape. The footboard is attached to the user's feet by a strap system, which holds the user's feet within recesses in the board itself. The footboard is preferably waterproof or water resistant for use on water trampolines, in lakes and swimming pools. Handgrips may be provided at one or more locations of the footboard, which, combined with the flexibility of the board, enhance the moves and style of the practicing foot boarder.

Abstract: A wheeled sport apparatus may comprise a platform and first and second sets of wheels disposed on the platform. Each set of wheels may include a center wheel between two outboard wheels and the outboard wheels may be toed outward for defining a turning radius. One or more carrier wheels may be provided between the first and second sets of wheels.

Abstract: In-one aspect, a leg activated brake for a foot supporting rolling device, such as a roller ski. Roller skis generally have one wheel mounted to each end of the foot supporting frame which houses a ski binding for the skier's boot. The brake system mounts to the frame of the roller ski and when the brake is activated by the leg, the brake applies frictional force to the rear wheel to stop the roller ski.

Abstract: A skate assembly has a boot having a substantially completely open base with a sole plate of more rigid material than the boot secured over the open base. The base has an opening extending along at least substantially the entire length of the boot from the heel to the toe, with side rims extending along opposite sides of the base opening. The sole plate may be releasably or permanently secured to the boot.

Abstract: An off road sports board provides a rider with the experience of snowboarding on dirt, gravel or other particulate materials when and where snow is not present, the sports board having an overall elongated oval configured deck having an upper surface having front and rear bindings within which the rider stands and a lower surface attaching a lower mounting plate from which extends a front fixed wheel assembly having a first lateral contoured wheel, an adjustable middle wheel assembly having a second lateral contoured wheel and a rear fixed wheel assembly having a third lateral contoured wheel, the first and third lateral contoured wheels having a smaller central diameter than a central diameter of the second lateral contoured wheel, wherein either the second and third lateral contoured wheel may be in contact with level ground at the same time, or the first and second lateral contoured wheels are in contact with level ground at the same time.

Abstract: An apparatus supporting “dry land” simulation of the diagonal stride cross-country skiing technique. The apparatus may include a roller ski comprising at least two wheel configured to roll on a surface and a stop connected to the roller ski. The stop may selectively engaging at least one of the surface and the at least two wheels in response to a force of at least a threshold magnitude urging the roller ski toward the surface to resist rearward roll of the roller ski on the surface. The resistance to rearward roll may vary with the force.

Abstract: The frame of an in-line skate (FIG. 8B) supports a wheel (10), allowing a skater to effectively slow down and stop, using an athletic stance that skiers on snow and ice skaters on ice use. The wheel (10) has a hub (20A), allowing a wheel to rotate around the axle (13A) vertically and at an inclination. The hub has axle roller bearings (23B). The wheel (10) includes friction band surfaces (11A) on the sides of the wheel. When rotating at an inclination the wheel's friction surface contacts a friction surface (11B), inside the wheel-well or an axle friction surface or a combination thereof to slow or brake the wheel. The wheel (10) assembly includes self-aligning springs (14A/B). Individual parts can be technically designed to allow various model solutions that will satisfy the abilities of a beginner to an expert. The wheel assembly frame can be attached to an in-line skate, an in-line skateboard, a downhill in-line ski and a downhill in-line skateboard.

Abstract: The invention relates to a roller ski comprising a ski body (1) having a front and a rear end. A wheel (2) is arranged at each end. The invention aims at providing a roller ski that resembles skiing on snow. In accordance with the invention the roller ski is provided with a wheel brake and a brake activator, which brake activator is arranged the wheel brake when a certain downward flexing of the ski is exceeded. The brake activator comprises electric brake activating means.

Abstract: A skateboard for use on a hard surface, configured to simulate the response of a snowboard, has a support platform to which sets of wheels are mounted. The wheels have successively decreasing diameters mounted on a common axle. The wheels of successively decreasing diameter may additionally or alternately be formed of materials of successively greater frictional and compressibility characteristics.

Abstract: A shoe-plate, adapted to hold a boot of a user, is pivotally mounted on the middle portion of an elongated frame. The frame has one or two rear wheels and a fork pivoted on its front portion around a vertical axis, and supporting a front wheel. Steering system connect the shoe-plate with the fork so that a pivotal movement of the shoe-plate causes a pivotal movement of the fork. The shoe-plate may be pivoted around a vertical or a longitudinal, horizontal axis. In the latter case, the skate also comprises adaptable restraining system connecting the trunk of the user to the frame.

Abstract: The frame of an in-line skate (FIG. 8B) supports a wheel (10), allowing a skater to effectively slow down and stop, using an athletic stance that skiers on snow and ice skaters on ice use. The wheel (10) has a hub (20A), allowing a wheel to rotate around the axle (13A) vertically and at an inclination. The hub has axle roller bearings (23B). The wheel (10) includes friction band surfaces (11A) on the sides of the wheel. When rotating at an inclination the wheel's friction surface contacts a friction surface (11B), inside the wheel-well or an axle friction surface or a combination thereof to slow or break the wheel. The wheel (10) assembly includes self-aligning springs (14A/B). Individual parts can be technically designed to allow various model solutions that will satisfy the abilities of a beginner to an expert. The wheel assembly frame can be attached to an in-line skate, an in-line skateboard, a downhill in-line ski and a downhill in-line skateboard.

Abstract: An all-terrain riding assembly comprised of a body member, including a supporting surface for feet of the user disposed between a front housing member having a rotatably mounted roller member and a rear housing member having a rotatably mounted, cylindrically-shaped roller member articulatedly mounted to the body member and including an assembly for controlling the rotational velocity of the rear roller member and thus linear velocity of the riding assembly.

Abstract: A simulator for snowboarding, skateboarding, water skiing and the like includes a substantially flat board having a support which permits three degrees of freedom of motion. The support can include a convex body which, in combination with a thrust receiving surface, forms a thrust bearing permitting the three degrees of freedom. The support can also include a rotary or turntable type of bearing permitting rotary motion. The simulator is instrumented to measure rotational motion and to provide an output signal compatible with a personal computer (PC) game port or a video game console input/output (I/O) port representative of rotational position of the board.

Abstract: A street ski comprising an elongated platform, a pair of trucks and a pair of wheels. Each truck includes a wheel support pivotably associated with the elongated platform and a spring connected to the wheel support for resisting pivoting of the wheel support relative to the elongated platform. Each wheel is rotatably mounted to the wheel support in any suitable manner such as by an axle or the like. In a preferred embodiment, the wheel support comprises a pair of fork members engaged with the axle. The truck permits rotation of the wheel support relative to the elongated platform in response to a shift in the weight of the rider of the board to simulate, for example, a snowboarding effect. The wheel supports desirably are raked in opposite directions to facilitate a fishtail effect or to otherwise facilitate a carving effect. Each truck includes a base rigidly secured to the elongated platform rotatably associating the wheel support with the elongated platform.

Abstract: A roller ski board similar to an ordinary snow ski board having a board body with bending elasticity and repellant property, and having at least one of single roller at its central portion and with or without smaller twin rollers at its front and rear edge portions, pivoted rotatively on an under surface of the board body along its longitudinal axis. The rollers have a lubricity and wear proof property with repellant elasticity so as to absorb the vibrations and shock added to the board from or to the ground during sliding. The rollers are arranged such that each external side periphery of the rollers is gradually wider from the central portion to a front and rear edge so that the external side peripheries of each roller does not protrude over the contour curvature of the board body. The rollers are also arranged consecutively from both the front and rear edges to the central portion such that each running surface of the rollers contacts with an arc curvature slightly curved upwardly over the ground.

Abstract: A skate board has a platform, at least one supporting frame integrally formed on a bottom surface of the platform and extending parallel to a longitudinal direction of the platform, and a plurality of wheel trucks fixed with the supporting frame. At least one plurality of assembly holes is defined in the supporting frame and a center of each hole follows a curved bottom end face of the supporting frame. Each one of the wheel trucks includes a wheel axle disposed substantially perpendicular to the longitudinal direction of the platform and extending through one of the plurality of assembly holes. At least two wheels are rotatably mounted on each wheel axle, whereby the skate board is intended to support a user operating in a pitching way to advance the skate board on the ground, so as to simulate sea surfing on the dry land.

Abstract: A roller ski board similar to an ordinary snow ski board having a board body with bending elasticity and repellent property, and having at least one of single roller at it's central portion and with or without smaller two twin rollers at it's front and rear edge portions, pivoted rotatively on an under surface of the board body along it's longitudinal axis. The all rollers have a lubricity and a wear proof property with repellent elasticity so as to absorb the vibrations and shock added to the board from or to the ground during sliding. The all rollers are arranged such that each external side periphery of the rollers is gradually wider from the central portion to a front and rear edge so that the external side peripheries of each roller does not protrude over the contour curvature of the board body.

Abstract: These and other objects of the present invention are achieved by an all-terrain riding assembly comprised of a body member, including a supporting surface for feet of the user disposed between a front housing member having a rotatably mounted roller member and a rear housing member having a rotatably mounted, cylindrically-shaped roller member. A plane defining the supporting surface is below a plane defined by the top portions of the front and rear roller members. In a particular preferred embodiment the rear housing member is articularly mounted to the main body member.

Abstract: A steerable wheel assembly for an in-line skate or roller ski comprises a hollow or dish-shaped wheel (11), a wheel bearing (13), and a wheel support (14) connecting the wheel (11) to a steering pivot (16) which is substantially disposed at a distance measured radially from the rotational axis of the wheel (11) where that distance is greater than the outer radius of the wheel bearing (13) and less than the outer radius of the wheel (11). Steering of the wheel occurs as the user's weight is displaced or the chassis of the device is inclined with respect to the ground toward the desired turning direction. A chassis for an in-line skate or roller ski containing a damping and centering force mechanism which may be used to moderate the behavior of a steering mechanism or suspension mechanism comprises a structural member (21), a damper housing (17), a damper piston (19), a fluid chamber (24), and a centering force mechanism (18).

Abstract: A roller-type skiing device, in particular a roller ski or a roller skiboard, includes a chassis defining a longitudinal axis and having an underside bounded by an envelope. Supported by the chassis is at least one row with a plurality of wheels which are evenly distributed over the entire underside and are rotatably mounted on axles arranged in parallel relationship to each other. The wheels are of varying length to conform to the contour of the envelope, with neighboring wheels defining a free intermediate space which is not significantly greater than an area covered by the wheels.

Abstract: A sliding exercise apparatus used as a recreational device. The device includes a sport board housed within a carrying case. The carrying case has at least a low friction and board protective bottom surface to facilitate sliding the apparatus upon a suitable contact area. The top of the carrying case is provided with removable portions that would enable the user to access the sports board while the board is housed within its carrying case. A user can be supported by the board while in its case and can employ the board and case to navigate upon a suitable support surface.

Abstract: A sled which will allow the user to experience the joy of sledding when there is no snow on the ground. The sled has wheel racks which are attached to the bottom of the base of the sled, and a plurality of oval wheels are attached to the wheel rack, and the wheels extend from adjacent the front of the sled to adjacent the rear of the sled. The foremost wheels on the wheel rack are smaller that the remaining wheels to allow the sled to be used on grassy surfaces which do not have snow thereon. The smaller wheels will make it easier for the sled to roll on non-linear hills.

Abstract: In one aspect, a roller ski is provided that includes a foot-supporting enclosure that enables the ski to be used without ski boots or ski bindings. In another aspect, a roller ski is provided that includes a cuff-actuated brake.

Abstract: A two-wheeled skateboard includes a board which is generally planar between a first position and a second position. A front wheel assembly is attached to the board at the first position and consists of a single front wheel. The front wheel assembly includes a front wheel support connected to the front wheel, a tension member connected to the wheel support and connected to the board at a connected position between the first position and the second position, and a rear wheel assembly attached to the board at the second load bearing position consisting of a single rear wheel. A clevis is connected to the tension member by a first clevis axis and connected to the wheel support by a second clevis axis such that a restoring tension is applied to the front wheel towards a longitudinal axis of the board through the first and second clevis axis while the front wheel assembly pivots with respect to the board.

Abstract: A roller board allowing the rider to slide laterally in a manner similar to a snowboard. The roller board is comprised of a platform having four fixed wheels, and two pivoting rollers positioned along the platform's longitudinal axis. The fixed wheels function similarly to conventional skateboard trucks. The pivoting rollers rotate to align themselves with the direction of force exerted on the platform. The pivoting rollers are spring biased to align themselves with the longitudinal axis of the platform. A height differential between the two types of rollers enables the rider to transfer weight from one type of roller to the other, alternating between the carving and sliding characteristics of a snowboard.

Abstract: A wheel-supporting hanger for utilization on the frame of a roller skate, this hanger having an upper mounting portion as well as front and back portions. A central cavity is defined in the front portion of the hanger, in which an axle-receiving member is operatively mounted in a cantilever manner. A wheel-supporting axle protrudes outwardly in a cantilever manner from the axle-receiving member, with a screw utilized on the outer end of the axle for retaining a skate wheel in an operative manner on the axle. A structural member is located in an upper part of the cavity, defining a substantially flat undersurface in a relatively closely spaced relationship to the axle-receiving member. The cantileverly mounted axle-receiving member, because of the mounting of the axle therein, is permitted to flex upwardly as well as to move laterally to a controlled extent should the wheel mounted on the axle encounter an obstacle or obstruction.

Abstract: A snow ski simulation apparatus which employs a plurality of in-line wheels mounted onto a longitudinally flexible ski chassis member having torsional rigidity which is generally greater than the longitudinal flexibility of the ski chassis. A simulated ski camber is created by providing in-line wheels positioned in spaced apart relationship along the longitudinal length of the ski chassis member. The differential diameter of the spaced-apart in-line wheels facilitates longitudinal flexion of the ski chassis member upon a user weighting or unweighting the ski apparatus in a manner which simulates snow skiing. In this manner the ability of the user to turn and modulate the arc of each turn by angulation relative to the running surface and weighting and unweighting of the ski apparatus is greatly enhanced.

Abstract: The present invention provides a turf board for simulating snowboarding on snowless terrain. The turf board includes a platform, two wheel assemblies and two bindings. Each of the wheel assemblies includes tires independently attached to a bottom surface of the platform by a shock absorber suspension. In a preferred embodiment, each of the wheel assemblies include a unique, three-piece rim which maintains the tire. The two bindings are attached to a top surface of the platform for securing a user to the turf board.

Abstract: A wheeled board apparatus has a platform with first and second concave portions. At least two primary wheels are located along a central longitudinal axis, with at least three outrigger wheels located generally along each concave sidecut.

Abstract: A roller board allowing the rider to slide laterally in a manner similar to a snowboard. The roller board is comprised of a platform having four fixed wheels, and two pivoting rollers positioned along the platform's longitudinal axis. The fixed wheels function similarly to conventional skateboard trucks. The pivoting rollers rotate to align themselves with the direction of force exerted on the platform. The pivoting rollers are spring biased to align themselves with the longitudinal axis of the platform. A height differential between the two types of rollers enables the rider to transfer weight from one type of roller to the other, alternating between the carving and sliding characteristics of a snowboard.

Abstract: A roller ski board similar to an ordinary snow ski board having a board body with bending elasticity and repellent property and a plurality of roller pairs pivoted rotatively on an under-surface of the board body along its longitudinal axis. The roller pairs have a lubricity and a wear proof property with repellent elasticity so as to absorb the vibrations and shock added to the board from or to the ground during sliding. The plurality of roller pairs are arranged such that the distance between the internal side peripheries of each roller pair is identical and between the external side peripheries is gradually wider from the central portion to a front and rear edge so that the external side peripheries of each roller pair does not protrude over the contour curvature of the board body. The roller pairs are also arranged consecutively from both the front and rear edges to the central portion such that each running surface of the rollers contacts with an arc curvature slightly curved upwardly over the ground.

Abstract: An in-line skateboard for supporting a rider with his feet in side-by-side relation one on each side of the longitudinal centerline of the board has a toe abutment wall for preventing forward movement of the rider's shoes and a heel support supporting the shoe heels at an elevation substantially above the surface of the board. The wheel base is very short, preferably no greater than the distance between the toe abutment and the heel support, to provide steering control by the rider by leaning the skateboard and shifting his weight to provide more or less weight on the front or rear wheels, respectively. The in-line wheels may be replaced with a single skate blade for using the skateboard on ice.

Abstract: A pair of roller skis 300 each constituted by attaching elastic wheels 302 to a boot-placing plate 301 in the front thereof and at the back thereof. The elastic wheels 302 each comprises a wheel supporting means having a circular rim part on the outer periphery and a tire part mounted on the circular rim part of the wheel supporting means and being elastically deformable in the direction perpendicular to the running direction of the wheel. Each elastic wheel 302 enables the running direction thereof to be simply changed with the wheel shaft kept in the same direction, and utilization of the features permits a skier to operate the roller skis with a feeling similar to that afforded by conventional snow skis.