FIELD OF THE INVENTION Embodiments of the present invention relate to an apparatus, system and computer program. In particular, though without prejudice to the foregoing, embodiments relate to an exercise device, system and computer program for performing and monitoring limb exercises. BACKGROUND TO THE INVENTION

It is desirable for a patient having undergone knee surgery to perform leg exercises so as to aid the rehabilitation process. Furthermore, it is desirable for a patient to perform leg exercises for training and "prehabilitation" purposes, for example prior to undergoing knee surgery.

The listing or discussion of any prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the present disclosure may or may not address one or more of the background issues. BRIEF DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

The present invention is as set out in the independent claims.

According to at least some embodiments of the invention there is provided an apparatus comprising: means for detecting a weight applied†o the apparatus; and means for sliding the apparatus along another surface separate of the apparatus.

According to at least some embodiments of the invention there is provided a system comprising the apparatus as set out above; and one or more further sensors, remote of the apparatus.

According to at least some embodiments of the invention there is provided a computer program that, when performed by at least one processor of a device, causes the device to: receive a signal transmitted from the apparatus as set out above, wherein the apparatus is remote of the device; and generate an output dependent upon the received signal. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of various examples of embodiments of the present invention reference will now be made, by way of example only, to the accompanying drawings in which:

Figure 1 schematically illustrates an apparatus according to an embodiment of the invention;

Figures 2a and 2b schematically illustrate a use of embodiments of the invention;

Figure 3 schematically illustrates an apparatus according to a further embodiment of the invention;

Figures 4a and 4b schematically illustrate a further use of embodiments of the invention;

Figures 5a and 5b schematically illustrate a yet further use of embodiments of the invention; Figure 6 schematically illustrates a block diagram of an apparatus according to a further embodiment of the invention; and

Figure 7 schematically illustrates a flow chart of a method according to an embodiment of the invention.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

The Figures schematically illustrate apparatus 100 comprising: means 101 for detecting a force applied to the apparatus; and means 102 for sliding the apparatus along another surface 103 separate of the apparatus 100.

Various non-limiting embodiments of the present invention seek to provide an apparatus, system and computer program for performing and monitoring leg exercises.

The means for detecting a weight applied to the apparatus may, for example, comprise a force or pressure sensor. The means is configured to detect and or measure a force/weight/load applied to the apparatus, for example such as a user placing his/her heel on top of the apparatus.

The means for sliding the apparatus may, for example comprise a sliding surface which, when in use, is in contact with the another surface separate of the apparatus. The means for sliding may be configured, such as via its shape and material, so as to enable and or facilitate the apparatus sliding along the another surface. For example a user resting his/her heel on the apparatus and moving his/her leg, e.g. bending his/her knee, so as†o cause the apparatus to the slide along the another surface.

Certain embodiments of the invention provide an improved apparatus that can facilitate the performance of various limb exercises as well as monitor the same, thereby aiding rehabilitation and training/prehabilitation of a user's limb. Limb exercises may include, for example, 'straight leg lifts', 'knee bends' and 'leg swings' . In some embodiments, the apparatus comprises means for outputting a signal from the means for detecting a force. The output means may be audio, visual or haptic output means to provide user feedback relating to the exercises being performed and monitored. Alternatively the output means may comprise means for transmitting signals from the apparatus to a remote device, i.e. so that audio, visual or haptic output means of the remote device might be employed to provide user feedback, tracking of progress and recording use of the apparatus. DESCRIPTION

An example of embodiments of the invention will now be described with reference to the Figures. Similar reference numerals are used in the Figures to designate similar features. For clarity, all reference numerals are not necessarily displayed in all figures.

In Figure 1 , only the functional components that are necessary for describing the operation of the device are discussed. Although embodiments of the apparatus are described in terms of comprising various components, it should be understood that the components may be embodied as or otherwise controlled by a corresponding processing element or processor of the apparatus. In this regard, each of the components described below may be one or more device, means or circuitry embodied in hardware, software or a combination of hardware and software that is configured to perform the corresponding functions of the respective components as described in greater detail below.

Figure 1 schematically illustrates an apparatus 100 according to an embodiment of the invention. The apparatus comprises means 101 for detecting a force or load 101 a applied to the apparatus. The force may correspond to a weight of at least a portion of a user's limb, such as a user's heel being placed upon / resting on an upper surface of the apparatus. The means 101 for detecting the force might comprise a force sensor, pressure detector or an equivalent structure.

In one embodiment the means comprises a capacitive sensor comprising two capacitive plates configured such that a separation between the plates is proportional to a force applied to the apparatus. I.e. such that a minimum plate separation distance is provided when there is no force applied to the device. Accordingly, a detection that the load has been removed from the apparatus is determined when the capacitive sensor indicates a minimum plate separation. The apparatus 100 also comprises, on its lower surface, a means 102 for sliding the apparatus along another surface 103, wherein the another separate surface is a surface separate of the apparatus. The sliding means 102 is configured so as to facilitate the apparatus to slide along, skid across or glide over the other surface, thereby enabling translational movement of the apparatus along the surface 103 by sliding/skidding/gliding of the apparatus 100 across the surface 103. The sliding means 102 may comprise a sliding surface, i.e. an external surface which, in use, is in contact with the surface 103. The sliding means may comprise a part of an external housing 104 of the device.

The sliding means 102 may comprise a rim or edge portion 106 which, when in use, is curved upwardly away from the surface 103. Furthermore, the sliding means may be substantially devoid of protrusions or recessions so as to avoid the apparatus from snagging or catching on the surface 103 and to facilitate the apparatus's sliding across the surface.

The sliding means 102 may be configured so as to have, for example, at least one of: a streamline shape, a substantially convex cross- sectional shape, and a substantially smooth surface. The sliding means may be substantially free from deformations and perturbations and have a low surface roughness. The sliding means may be made of a material that has a static and/or dynamic coefficient of friction with respect to the separate surface of: less than 0.5, or preferably less than 0.2, or more preferably less than 0.1 or yet more preferably less than 0.05.

The apparatus, on its upper surface, further comprises means 107 for coupling the apparatus to at least a portion of a limb of a user (not shown) or for engaging the apparatus with the limb portion. The limb portion may correspond to a leg or a heel of a user (when with or without clothing/footwear). The coupling means 107 may comprise an exterior surface having a substantially concave shape. Its cross- sectional shape may be substantially concave so as to form a depressed/recessed area with respect to the circumferential rim portion 106 of the apparatus 100. The depressed area may be configured in a shape complementary to the limb portion that is to be received, such as a heel of a user, so that the limb portion can abut against or mate within the concave surface.

The depressed area may further comprise cushioning or a deformable material that can mould/form around the shape of the limb portion to provide a secure and comfortable nest for the limb portion. Furthermore, the depressed area may comprise a grip/non-slip surface by which to engage with the limb portion and provide a form of frictional coupling of the limb portion to the apparatus, such that the frictional force between the limb portion and the coupling means 107 is greater than the frictional force between the sliding means 102 and the surface 103. Advantageously, this means that when a horizontal translational force is applied by the limb portion to the apparatus, the limb portion stays attached to the apparatus and does not slide off, but instead the apparatus slides across the surface, i.e. the apparatus is dragged across the surface by the limb portion. The apparatus may take on a substantially "saucer-like" shape with its concave surface 106 on the upper side of the apparatus opposite to the convex sliding surface 102 on the lower side.

Figures 2a and 2b schematically illustrate a use of embodiments of the invention, in particular in facilitating the performance of 'knee bend' exercises.

As shown in Figure 2a, a user 201 is lying down on the surface 103. For example, the user may be lying on the ground or on a bed, such that the surface may comprise, for example, a carpet or other flooring material or bed sheets or other bedding material. Initially, the user's upper leg 202, knee 203 and lower leg 204 are straight and the apparatus 100 is placed beneath the user's heel 205 such that the apparatus' sliding means 106 is in contact with the surface 103.

As shown in Figure 2b, when a user bends his/her knee 203 whilst keeping his/her heel 205 within the coupling means 106, this act applies a translational horizontal force to the apparatus via the user's heel. This causes the apparatus 100 to be dragged towards the user, i.e. from initial position 206a to 206b. The apparatus slides/skids/glides across the surface 103 via its sliding means 106 when dragged along by the user's heel.

Figure 3 schematically illustrates an apparatus 100 according to a further embodiment of the invention. This apparatus is similar to the one shown in Figure 1. However, the apparatus further comprises output means 301 . The output means receives signals from the means for detecting a force 101 as well as one or more further sensors 302, 303 and 304. These additional sensors may measure movement, acceleration or orientation and provide signals relating to the same to the output means 301 . The sensors may comprise, for example: accelerometers or gyroscopes.

The output means 301 may provide one of more of: audio, visual or haptic output based on the measurement signals from the sensors, for example via a speaker, display or vibrator. For example, an output may be provided which is triggered in dependence on a sensor signal to provide feedback to a user related to the exercises being performed, such as horizontal movement of the apparatus during a knee bend or detection of a straight leg lift as discussed below with respect to Figures 4a and 4b.

Alternatively, instead of providing: audio, visual or haptic output means within the apparatus to provide feedback to a user, the output means may comprise a communication interface for outputting sensor signals to a remote device (not shown), such as via wired or wireless communication. The remote device may be any suitable device capable of receiving sensor signals and providing an output related to the same, for example: a portable hand held electronic device, a mobile phone, a tablet, a PDA, a laptop, a PC, user programmable consumer electronic device or a server. The remote device may have additional functions besides receiving and outputting information from the apparatus. Advantageously, this leverages use of audio, visual or haptic output means provided on such (ubiquitous) remote devices, which a user may well already be in possession of. Also, off loading user feedback output functionality to a remote device saves on the costs of components, complexity of manufacturing and space/size of the apparatus which would otherwise be required to providing such features and functionality within the apparatus itself.

The output means 301 may comprise a communication interface and a transmitter, e.g. configured for short range wireless communication, such as: Bluetooth™ or infrared IRDA. The output means could be configured for WLAN, Wi-Fi or any other suitable wireless data transfer protocol.

The coupling means 106 for coupling the apparatus to a portion of a limb of a user may further comprises securing means 305 to attach the apparatus to the limb portion. The securing means may comprise any suitable means for releasably attaching the limb portion to the apparatus, for example so as to enable the apparatus to remain coupled to the user's limb portion even when the limb portion is raised off the ground. The securing means may comprise a member such as a strap 305 which goes around the limb portion and is secured to the apparatus at attachment points 306 and 307.

Figures 4a and 4b schematically illustrate a use of embodiments of the invention, in particular in facilitating the detection and/or monitoring of 'straight leg lift' exercises, wherein at least the entire lower leg is raised as a substantially straight unit.

As shown in Figure 4a, the user 201 is lying down on the surface 103. Initially, the user's upper leg 202, knee 203 and lower leg 204 are straight and the apparatus 100 is placed beneath the user's heel 205. The user's heel is resting on the apparatus which itself is disposed on the surface. In this state, a downwards force 205' due to the weight of the use's heel is applied to the apparatus. This is balanced by a reaction force 103' in an upwards direction from the surface 103. The means 101 for detecting a force applied to the apparatus detects the weight of the user's limb and is thereby able to determine that the limb is resting on the apparatus.

As shown in Figure 4b, when the user raises his/her leg keeping it straight, a translational vertical force is applied to his/her heel. This causes the weight of the heel 205' to gradually be removed from the apparatus 100. When the forces 205' and 103' are no longer detected the means for detecting a force applied to the apparatus determines that the weight of the user's limb has been removed, the limb has been raised up and is no longer resting on the apparatus. A signal from the means for detecting a force can be wireless transmitted to a remote device via output means 301 . The remote device 401 is configured to receive the signal from the apparatus 100 and generate an output based on the same so as to provide feedback to a user that he has successfully performed a straight leg lift and raised his/her leg up. Alternatively, where the apparatus comprises its own on board audio, visual or haptic output means, this could be triggered, e.g. an aural, visual or haptic alert could be emitted to provide feedback to the user informing the user that a straight leg lift has been accomplished.

As shown in Figure 4b, if the user continues to raise his/her leg upwards, the apparatus, which is attached to the user's limb portion via securing means 305, will be pulled upwards along with the raised leg and heel, thereby lifting up the apparatus from the surface 103 as shown with arrow 402. However, alternatively, where the apparatus is provided with no such securing means (as per the embodiment of Figure 1 ) the user's leg can be raised off the apparatus during a straight leg lift and the apparatus remains on the surface 103. The means for detecting a force determines that the user's limb portion has been lifted of the apparatus and transmits a signal to that effect to the remote device to provide an output for user feedback. Figures 5a and 5b schematically illustrate a use of embodiments of the invention, in particular in detecting and/or monitoring of 'leg swing' exercises and the degree of leg swing.

As shown in Figure 5a, the user 201 is standing upright with the user's upper leg 202, knee 203 and lower leg 204 all substantially straight and vertically aligned. The apparatus 100 is placed beneath the user's heel 205. In addition to the apparatus being secured to the user's heel, further additional sensors 501 and 502 separate from and remote of the apparatus are attachable to the user's limb, such as at the upper leg 202 and lower leg 204. These additional sensors measure and/or detect: at least one of: movement, acceleration and orientation. The sensors may comprise: an accelerometer, a gyroscope or a goniometers. Furthermore, the sensors are configured to transmit signals related to their measurements to the remote device 401 .

This system 500, comprising the apparatus 100 and the additional sensors 501 and 502, enables a determination and monitoring of a degree of swinging of the leg. Signals relating to this are transmitted to the remote device which provides feedback, such as visual feedback as shown in the figures, to the to the user.

In Figures 5a and 5b, additional sensors remote and external to the apparatus are provided. However, it is to be appreciated that the sensors could instead be provided internal of the apparatus as shown in Figure 3 with reference to sensors 302, 303 and 304, such that detecting and/or monitoring of leg swings can be effected with the apparatus itself without the need of additional remote sensors.

Figure 6 schematically illustrates a block diagram of an embodiment of the apparatus 100. The apparatus 100 may take the form of a medical device or an exercise device. The apparatus 100 comprises a controller such as a processor 601 and a memory 602 including computer program 603 comprising computer program instructions 604. The processor may also comprise an output interface 605 via which data and/or commands are output by the processor and an input interface 606 via which data and/or commands are input to the processor.

Implementation of controller can be in hardware alone (a circuit), have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware) . The computer program 603 may be stored on a computer readable storage medium 607 (disk, memory etc). The apparatus further comprises: one or more sensors 101 , 302, 303 and 304, one or more output means 301 , 301 a-c. The output means 301 may comprise a transceiver configured for wireless communication with a remote device (not shown). The output means 301 a-c may comprise audio, visual and haptic output means.

The computer program 603 comprises computer program instructions 604 that control the operation of the apparatus 100 when loaded into the processor 601 . The computer program instructions provide the logic and routines that enables the apparatus to cause the apparatus 100 at least to:

receive sensor measurements from the one of more sensors 101 ,

303, 304, 305; and

transmit signals related to the sensor measurements to a remote device.

Figure 7 schematically illustrates a flow chart 700 of a method according to an embodiment of the invention. The blocks illustrated in Figure 7 may represent steps in a method and/or sections of code in a computer program for the remote device, i.e. so as to configure the remote device for use with the apparatus and control the remote device†o operate in a particular manner in response to receipt of information from the apparatus.

In block 701 , a signal is received by the remote device 401 from the apparatus 100. In block 702, an output is generated at the remote device which is dependent upon the received signal. The output may be an audio, visual or haptic output for providing feedback to a user when performing leg exercises. Additionally, the received signals relating to sensor measurements of the apparatus may be stored so as to track progress of a user's rehabilitation/training. Furthermore, the sensor measurements may be sent from the remote device to further devices/people, such a physiotherapists, doctors or other medical practitioners. The procedures described above may be embodied by computer program instructions. In this regard, the computer program instructions which embody the procedures described above may be stored by a memory storage of the remote device and performed by a processor of the remote device.

Embodiments of the invention have been described using schematic block diagrams and flowchart illustrations. It will be understood that various blocks can involve implementation by a combination of hardware and computer program instructions of a computer program. These program instructions may be provided to one or more controllers or processors such that the instructions which execute on the processor create means for implementing the functions specified in the block or blocks. The computer program instructions may be executed by the processor to cause a series of operational steps to be performed by the processor to produce a computer implemented process such that the instructions which execute on the processor provide steps for implementing the functions specified in the block or blocks.

Accordingly, the blocks support: combinations of means for performing the specified functions; combinations of steps for performing the specified functions; and computer program instructions for performing the specified functions. It will also be understood that each block, and combinations of blocks, can be implemented by special purpose hardware-based systems which perform the specified functions or steps, or combinations of special purpose hardware and computer program instructions.

In the description above, the wording 'couple' and 'communication' as well as their derivatives mean operationally connected and in operational communication respectively. It should be appreciated that any number or combination of intervening components can exist (including no intervening components). For example, the user's heel being coupled to the apparatus encompasses a coupling of the user's limb both with and without socks and/or shoes on. The communication between the apparatus and the remote device may be direct or indirect via other 3 ^rd party devices, such as a router.

Embodiments of the present invention provide apparatus consisting of various modules or means that provide the functionality described above. The modules or means may be implemented as hardware, or may be implemented as software or firmware to be performed by a computer processor. In particular, in the case of firmware or software, embodiments of the invention can be provided as a computer program product including a computer readable storage structure embodying computer program code (i.e. the software or firmware) thereon for performing by the computer processor.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. Although various embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example whilst embodiments have been described with respect to a leg exercise/monitoring device, it will be appreciated that embodiments could provide an exercise/monitor device for other limbs, such as portions of a user's arm.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.