Field of the Invention

This invention relates to a sensor mat or device for timing of athletic movement in relation to the ground, in particular but not only to a jump mat which responds rapidly to the weight of an athlete and thereby enables accurate determination of timing data.

Background to the Invention A wide range of athletic endeavors involve the ability of an athlete to drive quickly off one foot, to leap quickly with two feet, or to make contact with the ground for the least possible time between steps or jumps. For example, a standing jump performed by an athlete can be quantified by the athlete's Contact time Tc, and flight time Tf, these being the time spent on a mat between successive jumps, and the time spent in the air during a jump.

Similarly, the time of contact made with the ground by sprinters, long jumpers and high jumpers tends to reduce with increased performance so that measuring the time of contact is a useful measure of athletic performance in these and other athletic endeavors. Ratios of these Tc and Tf times also reveal information about power generation, muscle stiffness and fatigue.

Such time periods can be small fractions of a second, and improvement in an athlete over time, or differentiation between respective performances, must be measured accurately on the order of milliseconds, in order to

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(Rule 26) RO/AU provide meaningful measures of athletic performance. Such measurements must also be made without interfering with the ability of the athlete to carry out their movements. Restriction of airflow in the mat has been found to be a limiting factor in accuracy of the measurements.

Summary of the Invention

It is an object of the invention to provide a sensor mat for accurate timing athletic jumps, or at least to provide an alternative to existing mats of this general kind.

In one aspect the invention therefore resides in a sensor mat for an athlete, including: a bottom plate supported on a base, a top plate held apart from the bottom plate forming a cavity between the plates, circuitry associated with the top and bottom plates which times contact between the plates due to weight of the athlete on the top plate, wherein the bottom plate includes airflow passages which assist airflow in the cavity during movement between the plates.

Preferably the mat has a pair of bottom plates side by side corresponding to individual feet of the athlete. The action of weight through each foot can thereby be timed.

Airflow in the cavity can assisted by an arrangement of slots in the bottom plate and/or lateral vents which assist airflow in and out of the cavity.

Resilient means such as an array of conical springs is preferably provided between the top and bottom plates.

In one embodiment the top and bottom plates are stainless steel plates, held apart by strips of tape along edges of the plates, forming part of an

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(Rule 26) RO/AU electrical circuit which is switched by the weight of the athlete.

Brief Description of the Drawings

Embodiments of the invention will be described with reference to the drawings, of which:

Figure 1 is an exploded view showing the main components of a jump timing device according to the invention,

Figure 2 is a cross section in perspective showing details of a bottom plate and a base in the device,

Figure 3 is a cross section also showing details of the bottom plate and base in the device,

Figure 4 outlines circuitry associated with timing and user features of the device.

Description of the Preferred Embodiments

Referring to the drawings it will be appreciated that the invention can be performed in a variety of different ways for a range of athletic purposes and that these embodiments are given by way of example only.

Figure 1 shows a device 100 for measuring contact and flight times of an athlete, namely a jump mat in this embodiment. The mat has a top plate 110 held apart from a pair of bottom plates 150, by a peripheral strip 130, to form a cavity 120. The plates are typically cut from stainless steel while the strip is formed by pieces of double sided adhesive foam tape which separate and secure the plates. The bottom plate is supported by a base

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(Rule 26) RO/AU 170 which rests on the ground during use. The plates and base are contained by an edge or rim 180. The base is typically formed from a manufactured wood such as MDF but foam plastic or a laminate structure could also be suitable. The edge is typically formed from plastic.

The top and bottom plates are each about 0.5 to 1mm in thickness and separated by a cavity of about 0.5 to 1.5mm, while the base is about 1cm in thickness. Placed together in the rim they form a mat of about 80cm by 80cm in area and 1 - 1.5 cm in thickness. The pair of bottom plates are each about 40cm in width separated by a centre strip 154 and are provided for the individual feet of an athlete jumping from and/or landing on the mat. The centre strip may be overlaid by a length of peripheral strip 130. These dimensions and the resilience of the mat are variable depending on the specific purpose of the mat and the materials used. In a simpler embodiment a single bottom plate may also be provided rather than a pair.

A printed circuit board 140 fits in pocket 172 cut into the base 170, with corresponding portions 112 and 152 cut into the top and bottom plates 110 and 150. Plate 114 protects the PCB. The PCB provides circuitry which is electrically connected to the top and bottom plates, typically by way of a simple screw connection. The top plate 110 and the pair of bottom plates 150 thereby form a pair of switches which are activated by the weight of an athlete on the mat. A switch is closed when the top plate is depressed into electrical contact with one or other of the bottom plates by one or other of the athlete's feet. The arrival and departure of either or both feet can then be timed and analysed with suitable accuracy, preferably within about 1ms.

Figure 2 shows a portion of the base 170 and one of the bottom plates 150

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(Rule 26) RO/AU in more detail. The base preferably contains an array of conical springs 160 located in respective pockets 162 of the base and extending through corresponding holes in the bottom plate. The springs are seated in the base and contact the underside of the top plate. Resilience of the springs compensates or offsets the weight of the top plate when the top plate is depressed towards either of the bottom plates and assists a rapid rebound of the top plate when the athlete weight is removed. The strength and location of the springs 160 should be optimised for the weight of the particular top plate. In this embodiment the springs provide 200g force at 0.5 mm compression for a 1mm top plate, and are positioned in two 3x7 arrays. Conical springs are more readily compressed than cylindrical springs and avoid contact with the bottom plate. A single resilient member between the top and bottom plates, such as a single central spring or a layer of foam, could be used in some embodiments.

Figure 3 shows in more detail how airflow through the cavity 120 is improved by way of slots 156 cut in each of the bottom plates 150. These slots are about 1mm in width and preferably arranged laterally along each plate spaced by approximately 1cm. The slots begin about 1cm from the centre strip and end about 1cm from the rim 180. Slots or perforations or similar may be provided within the mat in a variety of patterns. A series of vents 190 at the edge of the mat may also be provided assist airflow in and out of the cavity. These vents are each formed by a recess 192 near the edge of the base 170 with a corresponding hole in the bottom plate. A tube 196 extends laterally from each recess through the rim 180 and contains a filter 198. Preferably the holes in the bottom plate are joined by one of the slots 156. Vents may be provided along one or more parts of the mat in a variety of patterns.

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(Rule 26) RO/AU Figure 4 shows circuitry on the PCB 140 and indicates optional user details of the mat. The circuitry includes a microprocessor 141 and memory 142, and also radio transceiver 143 through which the microprocessor communicates to a supervisory device 200 such as an IPad. Switches 144 formed by the top plate and either of the pair of bottom plates are monitored by the microprocessor. Contact between the top and bottom plates caused by the weight of an athlete's foot on either side of the top plate closes an electrical circuit to activate or deactivate each switch.

Actual switching times or simply contact event data for each foot are thereby detected by the microprocessor and are transmitted to the supervisory device. A visual indicator 145 such as an LED and audio indicator 146 such as a speaker may provide feedback to the athlete.

Battery 147 and charging unit 148 provide power to the circuitry.

It will be appreciated that the mat can be constructed with a range of materials and dimensions for a range of purposes. Airflow in the cavity can be enhanced by passages or vents of the kind described, leading to faster responses by the mat and more accurate timing data.

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(Rule 26) RO/AU