A WEARABLE DEVICE AND ASSOCIATED METHODS AND SYSTEMS

Abstract

Systems and methods for monitoring acute:chronic workload ratio (ACWR) are described. An indicator of workload is received from a device worn or carried by a user. An acute workload is determined for the user based on the received indicator of workload over a first period of time. A chronic workload is determined for the user based on the received indicator of workload over a second period of time, where the first period of time is shorter than the second period of time. A current ACWR is determined for the user based on the acute workload and the chronic workload.

Claims

1. A system for monitoring acute:chronic workload ratio (ACWR), the system including at least one processor configured to perform a method of: receiving an indicator of workload from a device worn or carried by a user; determining an acute workload for the user based on the received indicator of workload over a first period of time; determining a chronic workload for the user based on the received indicator of workload over a second period of time, where the first period of time is shorter than the second period of time; and determining a current ACWR for the user based on the acute workload and the chronic workload.

2. The system of claim 1, wherein the device is configured to measure an angle of rotation of a joint to which the device is mounted.

3. The system of claim 2, wherein the acute workload and the chronic workload are determined based on an accumulation of the angle of rotation of the joint over time.

4. The system of claim 1, wherein the device is configured to measure one or more of: distance travelled by the user, and one or more indicators of activity or posture by the user.

5. (canceled)

6. The system of claim 1, including estimating joint load of the user based on the received indicator of workload in conjunction with biomechanical modelling, and determining the acute workload and the chronic workload based on the estimated joint load.

7. The system of claim 1, wherein the chronic workload is determined as an average value of workload over the second period of time.

8. The system of claim 1, wherein the at least one processor is configured to determine a current risk level to the user based on the current ACWR.

9. The system of claim 8, wherein determining the current risk level includes comparing the current ACWR against one or more predetermined thresholds.

10. The system of claim 9, wherein the predetermined thresholds include a first threshold associated with a cautionary risk level, a second threshold associated with a warning risk level, and a third threshold associated with an alert risk level.

11. The system of claim 9, wherein the one or more predetermined thresholds are dynamic.

12. The system of claim 11, wherein the one or more predetermined thresholds increase based on time since an event.

13. The system of claim 11, wherein the one or more predetermined thresholds are adjusted based on performance metrics of the user.

14. The system of claim 1, wherein the at least one processor is configured to issue a notification based on the current risk level.

15. The system of claim 14, wherein the notification conveys information to the user regarding recommended activity based on the current risk level.

16. A computer-implemented method of monitoring acute:chronic workload ratio (ACWR), including: receiving an indicator of workload from a device worn or carried by a user; determining an acute workload for the user based on the received indicator of workload over a first period of time; determining a chronic workload for the user based on the received indicator of workload over a second period of time, where the first period of time is shorter than the second period of time; and determining a current ACWR for the user based on the acute workload and the chronic workload.

17. The computer-implemented method of claim 16, wherein the device is configured to measure an angle of rotation of a joint to which the device is mounted, and the acute workload and the chronic workload are determined based on an accumulation of the angle of rotation of the joint over time.

18. (canceled)

19. (canceled)

20. (canceled)

21. (canceled)

22. (canceled)

23. The computer-implemented method of claims 16, including determining a current risk level to the user based on the current ACWR.

24. The computer-implemented method of claim 23, wherein determining the current risk level includes comparing the current ACWR against one or more predetermined thresholds.

25. (canceled)

26. The computer-implemented method of claim 24, wherein the one or more predetermined thresholds are dynamic.

27. (canceled)

28. (canceled)

29. The computer-implemented method of claim 23, including issuing a notification based on the current risk level.

30. (canceled)

Description

5 BRIEF DESCRIPTION OF THE DRAWINGS

[0050] One or more embodiments of the disclosure will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

[0051] FIG. 1 is a schematic diagram showing features of a wearable device system according to an aspect of the present technology;

[0052] FIG. 2-1 is a front perspective view of an exemplary wearable device in the form of a knee brace according to an aspect of the present technology;

[0053] FIG. 2-2 is a front perspective view of another exemplary wearable device in the form of a knee brace according to an aspect of the present technology;

[0054] FIG. 3 is a front view of an exemplary wearable device in the form of an elbow brace according to an aspect of the present technology;

[0055] FIG. 4-1 is a side view of an exemplary wearable device mounted to a standing wearer, configured to be aligned with a coordinate system according to an aspect of the present technology;

[0056] FIG. 4-2 is a side view of the exemplary wearable device mounted to a seated wearer, configured to be aligned with a coordinate system according to an aspect of the present technology;

[0057] FIG. 4-3 is a front perspective view of an exemplary wearable device to be mounted to a wearer, having a visual indicator of alignment according to an aspect of the present technology;

[0058] FIG. 4-4 is a top view of an exemplary wearable device, having a visual indicator of alignment according to an aspect of the present technology;

[0059] FIGS. 5-1 to 5-3 are front views of an exemplary wearable device mounted to the leg of a wearer for measuring angulation of the leg according to an aspect of the present technology;

[0060] FIG. 6-1 is a side view of an exemplary wearable device mounted to a leg of a wearer, for measuring joint laxity according to an aspect of the present technology;

[0061] FIG. 6-2 is a side view of an exemplary joint mechanism for a wearable device according to an aspect of the present technology;

[0062] FIG. 7 illustrates a sensor arrangement for sensing characteristics of patella movement according to an aspect of the present technology;

[0063] FIG. 8 is a flow diagram of an exemplary method of monitoring workload of a wearer of a wearable device according to aspects of the present technology.

6 DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

[0064] It will be understood that the particular examples described herein are not intended to be limiting to all embodiments of the present technology. The various examples may share one or more common characteristics and/or features. It should be appreciated that one or more features of any one example may be combinable with one or more features of one or more other examples.

[0065] 6.1 Exemplary Wearable Device System

[0066] FIG. 1 is a schematic illustration showing features of a system 100 according to certain embodiments of the technology. The system 100 includes one or more wearable devices 102 (for example, knee orthosis 102-1 and/or elbow orthosis 102-2) configured to be mounted to a corresponding body part (s) of a body of a patient 104 in use. In examples, the system 100 further includes one or more reference sensors, including intelligent user devices 106 (for example, smart phone 106-1 and/or smart watch 106-2) and/or dedicated reference sensor devices 108 (for example, an inertial measurement unit (IMU) 108-1 and/or smart insole 108-2).

[0067] In exemplary embodiments, data from one or more of the wearable devices 102, user devices 106, and/or reference sensor device 108 may be communicated to a remote processing service 110 via a network 112 (for example a cellular network, or another network potentially comprising various configurations and protocols including the Internet, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies—whether wired or wireless, or a combination thereof). For example, the smart phone 106-1 may operate an application capable of interfacing with the data management service 110.

[0068] Among other functions, the remote processing service 110 may record data, perform analysis on the received data, and report to one or more user devices. In this exemplary embodiment, the remote processing service 110 is illustrated as being implemented in a server—for example one or more dedicated server devices, or a cloud based server architecture. By way of example, cloud servers implementing the remote processing service 110 may have processing facilities represented by processors 114, memory 116, and other components typically present in such computing environments. In the exemplary embodiment illustrated the memory 116 stores information accessible by processors 114, the information including instructions 118 that may be executed by the processors 114 and data 120 that may be retrieved, manipulated or stored by the processors 114. The memory 116 may be of any suitable means known in the art, capable of storing information in a manner accessible by the processors, including a computer-readable medium, or other medium that stores data that may be read with the aid of an electronic device. The processors 114 may be any suitable device known to a person skilled in the art. Although the processors 114 and memory 116 are illustrated as being within a single unit, it should be appreciated that this is not intended to be limiting, and that the functionality of each as herein described may be performed by multiple processors and memories, that may or may not be remote from each other.

[0069] The instructions 118 may include any set of instructions suitable for execution by the processors 114. For example, the instructions 118 may be stored as computer code on the computer-readable medium. The instructions may be stored in any suitable computer language or format. Data 120 may be retrieved, stored or modified by processors 114 in accordance with the instructions 118. The data 120 may also be formatted in any suitable computer readable format. Again, while the data is illustrated as being contained at a single location, it should be appreciated that this is not intended to be limiting—the data may be stored in multiple memories or locations. The data 120 may include databases 122 storing data such as historical data associated with one or more of the one or more of the wearable devices 102, user devices 106, and/or reference sensor devices 108, and the results of analysis of same.

[0070] It should be appreciated that in exemplary embodiments the functionality of the remote processing service 110 may be realized in a local application (for example, on smart phone 106-1, or another personal computing device 124), or a combination of local and remote applications. Further, it should be appreciated that data may be transferred from one or more of the devices by other means—for example wired communication links, or transfer of storage devices such as memory cards.

[0071] The results of analysis, and/or underlying data, may be displayed on any suitable display device—for example smart phone 106-1, or computing device 124.

6.2 Knee Brace

[0072] FIG. 2-1 shows an exemplary wearable device in the form of an orthosis system particularly suited for mounting proximate a knee (not shown) of the patient (not shown)—herein referred to as first knee brace 200-1—as described in PCT application PCT/NZ2018/050085, the contents of which are incorporated herein by reference. In this embodiment, the knee brace 200-1 includes a body mounting portion having a first brace portion 202-1 and a second brace portion 202-2. In use, the first brace portion 202-1 is mounted upwardly of the knee of the patient and the second brace portion 202-2 is mounted downwardly of the knee of the patient. The first brace portion 202-1 and the second brace portion 202-2 are pivotably coupled via pivot assemblies 204-1 and 204-2. This makes the orthosis system 200-1 suited to use in bracing a pivoting joint of the body, such as the knee.

[0073] In other embodiments of the invention the first and second brace assemblies are moveably coupled in some other manner, for example through a sliding coupling. Such embodiments may be suitable for use in bracing an extendable part of the body, for example. In yet other embodiments, the brace of an orthosis system may be provided as a flexible sleeve, such as a continuous compression sleeve. A first portion of the sleeve is a first body mounting portion to be worn on one side of the wearer's joint, and a second portion of the sleeve coupled to (i.e. integrally formed with) the first portion is a second body mounting portion to be worn on an opposite side of the wearer's joint. In the embodiment illustrated, modules 206-1 and 206-2 are removably coupled to the pivot assemblies 204-1 and 204-2. One or both of the modules 206-1 and 206-2 may be configured as sensing modules. While the modules 206-1 and 206-2 are illustrated as being on the sides of the patient's knee, in other embodiments the orthosis system may be configured to mount modules in other positions in relation to the body.

[0074] FIG. 2-2 shows a second knee brace 200-2 includes a body mounting portion having a first brace portion 202-1 and a second brace portion 202-2. In use, the first brace portion 202-1 is mounted upwardly of the knee of the patient and the second brace portion 202-2 is mounted downwardly of the knee of the patient. In this exemplary embodiment, the brace portions 202 are stiff arms (for example made of aluminium) having strap mounting features (for example slots 208) for positioning flexible straps (not illustrated) for mounting the knee brace 200-2 to a wearer. In this embodiment, sensing module 206 is removably coupled to the pivot assembly 204 of the knee brace 200-2. The sensor module 206 includes a rotational knee movement sensor, and an IMU for sensing of thigh movement.

6.3 Elbow Brace

[0075] FIG. 3 shows an exemplary wearable device particularly suited for mounting proximate an elbow (not shown) of the patient (not shown)—referred to herein as elbow brace 300—as described in PCT application PCT/NZ2018/050085, the contents of which are incorporated herein by reference. It will be noted that the body mounting portion in this embodiment comprises a first brace portion 302-1 configured to wrap around a first portion of the patient's arm. Similarly, the second brace portion 302-2 is configured to wrap around another portion of the patient's arm. The first brace portion 302-1 and the second brace portion 302-2 are pivotably coupled via pivot assembly 304-1, to which a sensor module 206 is mounted.

6.4 Sensing Module

[0076] Exemplary embodiments of the sensing module 206 comprises sensor components configured to detect, record, process and/or transmit data relating to the movement and/or rotation of the orthosis system or components thereof. The sensor components may additionally or alternatively detect, record, process and/or transmit data pertaining to the patient's physical activity and/or physiology. This may include parameters such as joint kinematics (such as joint angle, joint velocity, joint torque, and/or joint acceleration), limb accelerations, limb rotations, limb and/or joint loads, muscle force, muscle strength, muscle velocity, electrical activity, temperature, pH, perspiration, heart rate, blood pressure and/or other bio-signals. Example sensors include rotary encoder, optical and magnetic sensors.

[0077] The sensing module 206 may comprise further components to enable the detection and recording of such data. For example, the sensing module 206 may comprise an accelerometer, gyroscope and/or magnetometers. The sensing module 206 may additionally or alternatively comprise physiological sensors, for example a thermometer, electromyography (EMG) sensor, heart rate sensor, blood pressure sensor, blood oxygen level sensor, etc.

[0078] Sensing module 206 may comprise a transmitter for transmitting data and/or signals obtained by or through the sensor components to a remote location, for example by RF, Bluetooth, Wi-Fi or any other remote communication protocol. Sensing module 206 may also comprise one or more processors configured to process the data/signals. The sensor components may further comprise a receiver configured to receive data/signals remotely from an external source, such as external control signals. Data may be stored or received by the sensing module 206 through a physical data storage device such as a memory card, USB stick or the like.

[0079] Other sensors may be provided, comprised in or separate from a sensing module 206. For example, the wearable device 200 may also comprise a torque sensing module comprising one or more sensors for monitoring joint interaction torque between the patient and the body mounting portion. For example, such a sensor(s) may monitor relative displacement between two or more components of the device 200, for example the first and second brace portions respectively, to enable a torque sensor to sense torque between the first and second brace portions. Torque sensing may be performed when the first and second brace portions are locked, or there is some resistance between them. It should therefore be appreciated that a torque sensing module may also incorporate a locking mechanism to substantially prevent movement (e.g. rotation) between the first and second brace portions, such as described in PCT application PCT/NZ2018/050085.

[0080] A person skilled in the art will understand that a number of sensor types may be suitable for measuring characteristics of a patient's biomechanics. For example, a rotary encoder may be used to measure an angle of displacement between the first and second brace portions. Alternatively or additionally an inertial measuring unit(s) (IMU) may be attached to one or each of the first and second brace portions to measure the angle of displacement. An angle of displacement may be used to infer a resistance to motion level, by calibration of a known resistance element with respect to the amount of relative movement between the brace assemblies, or conversely a resistance measurement such as torque or force may be used to infer angle. A strain gauge may be provided to a compliant/resilient element such as a spring or elastomeric block to measure force or torque, and/or a position of a spring element may be used to indicate a resistance to motion level.

6.5 Aligning Wearable Device

[0081] In certain forms of the present technology, real-time feedback of the orientation of at least one component of the wearable device is provided in order to enable determination of orientation relative to a reference coordinate system.

[0082] FIG. 4-1 shows an exemplary wearable device in the form of a third knee brace 200-3, mounted to the knee of wearer 104. The knee brace 200-3 is configured to provide a visual indication of orientation of the knee brace 200-3 to a reference coordinate system. In examples, the knee brace 200-3 may include visual indicators at a central location 400 (for example on a pivot assembly 204), an upper location 402-1 on upper brace portion 202-1, and/or a lower location 402-2 on lower brace portion 202-2.

[0083] In a first example, the visual indicator may be provided by a spirit level 404. In the example illustrated in FIG. 4-1, the spirit level 404 is intended to be horizontal when the knee brace is generally vertical in orientation (i.e. is configured to indicate vertical orientation). In order to align the knee brace 200-3, the wearer 104 may stand up straight to provide a reference, and the knee brace 200-3 moved to obtain a vertical orientation using the spirit level 404. In an alternative example utilising a spirit level, as illustrated in FIG. 4-2, the spirit level 404 is intended to be horizontal when the knee brace is generally horizontal in orientation (i.e. is configured to indicate horizontal orientation). In order to align the knee brace 200-3, the wearer 104 may sit or lie down on the ground or another level surface (such as on a bed or bench) such that their leg is fully extended to provide a reference, and the knee brace 200-3 moved to obtain a horizontal orientation using the spirit level 404.

[0084] In a second example, the knee brace 200-3 may include an orientation sensor, for example an IMU, configured to determine orientation of the knee brace 200-3. A visual indicator may be provided in the form of a light 406, illuminated to indicate the orientation of the knee brace 200-3. In the example illustrated, a first light 406-1 and a second light 406-2 are provided. The first light 406-1 may be illuminated when the knee brace 200-3 is vertical—i.e. straight up and down relative to the ground—while the second light 406-2 may be illuminated while the knee brace 200-3 is not vertical. In an alternative example, a single light such as a multi-colour LED may be used to indicate different states of orientation (e.g. a first colour indicating alignment with vertical, and a second colour indicating non-alignment).

[0085] In alternative examples, an audible indicator (for example, a buzzer) and/or a haptic feedback indicator (for example, a vibration generator) may be used to indicate alignment or non-alignment.

[0086] In a third example, referring to FIG. 4-3, a visual indicator (in this example a vertical line 408-1) may be provided on a strap 210 of the knee brace 200-3. The vertical line 408-1 may be releasably attached to the strap 210 (for example using hook and loop material, snap fasteners, clips, or any other suitable means) to allow for placement at the front of the wearer's leg on the sagittal plane in a forward walking direction. Releasable attachment allows for placement based on the circumference of the wearer's leg, such that the vertical line 408-1 is accurately positioned in the front of the leg. If the knee brace 200-3 becomes misaligned during use, for example by twisting about the wearer's leg, this may be detected through observation of the position of the vertical line 408-1.

[0087] In a further example shown in FIG. 4-4, a raised visual indicator 408-2 may be provided on a dedicated support member 410 extending around at least a portion of the wearer's leg 106 from another component of the wearable device (for example a brace portion 202). In examples, the visual indicator 408-2 may be releasably attached to the dedicated support member 410 in order to align its position relative to the sagittal plane in front of the wearer's leg. In alternate examples the dedicated support member 410 may be moveable relative to the wearable device, for example a ratcheting rigid strap, or sliding arm.

[0088] According to an aspect of the present technology there is provided a calibration method for one or more sensors associated with the wearable device. In examples in which the wearable device has one or more sensors, it may be desirable to calibrate those sensors in order to relate the sensor output to one or more of the wearer's body parts, for error compensation, and/or to maintain accuracy (e.g. to compensate for sensor drift).

[0089] In the example of a knee brace 200-3 as shown in FIG. 4-1, sensors may be provided for measuring angles between the body mounting portions 202-1 and 202-2. It may be desirable to calibrate the sensors using a reference point, such as the wearer standing straight (during which times the angles should be zeroed). Such calibration may be performed before, after, and/or during a monitored activity.

[0090] In certain forms of the present technology, calibration may be performed on receiving a user input while in a predetermined position to provide a reference. For example, the user input may be provided by selection of a physical button 410 on the knee brace 200-3. In another example, the user input may be received on selection of a virtual selectable element on a graphical user interface displayed on smart phone 106-1.

[0091] In examples, calibration may be performed automatically on detection of a predetermined event or activity. For example, the posture of the wearer 104 during activity may be monitored using one or more motion or orientation sensors, and a standing upright posture may be identified within this activity. On detecting the standing upright posture, the sensors may be calibrated accordingly (for example, providing a zero reference for angle sensors of knee brace 200-3. As a further example, the system may provide a message to the wearer asking them to confirm if they are standing upright, and if the user indicates that they are, then the system calibrates.

6.6 Joint Characteristic Measurement

[0092] In certain forms of the present technology, a wearable device is configured to measure at least one characteristic of a joint, or a body part associated with a joint, of a wearer.

[0093] In a first example, a wearable device configured to measure angulation of a bone or joint of a wearer. For example, the wearable device may be configured to measure varus deformity, or valgus deformity. Referring to FIG. 5-1, a knee brace 500 includes a central portion 502, a first body mounting portion in the form of upper strut 504-1, and a second body mounting portion in the form of lower strut 504-2. The upper strut 504-1 and the lower strut 504-2 are made of a flexible material which retains sufficient rigidity to hold its form in the absence of loading, but flexes in the frontal plane. Flex sensors (not illustrated), are provided to output a signal indicative of the relative angle(s) between the upper strut 504-1 and the lower strut 504-2, and/or the central portion 502 and the upper strut 504-1 or the lower strut 504-2.

[0094] In the example shown in FIG. 5-2, the leg of the wearer (including upper leg 506-1 and lower leg 506-2) displays a valgus deformity in which the bone segment distal to the knee joint (i.e. the lower leg 506-2) is angled outward—i.e. angled laterally, away from the body's midline. The output of the flex sensor(s) enables a determination of the relative angle.

[0095] Conversely, in the example shown in FIG. 5-3 the leg of the wearer (including upper leg 506-1 and lower leg 506-2) displays a varus deformity in which the lower leg 506-2 is angled inward (i.e. angled laterally towards the body's midline). Again, the output of the flex sensor(s) enables a determination of the relative angle.

[0096] In examples, the wearable device may be configured to measure angulation in a single direction—for example the flex sensor may only exhibit a change in output due to angulation in a particular direction from a zero-reference position. In alternative examples, the wearable device may be configured to measure angulation in a both directions (e.g. inwards and outwards)—for example using a bi-directional flex sensor, or multiple flex sensors where one set is used for inward angulation and another set is used for outward angulation. In configurations where a bi-directional flex sensor is used, it is envisaged that a determination of the direction may be required using separate means to the flex sensor output alone—for example via user input or another sensor.

[0097] In an alternative example which is not illustrated, the wearable device may take the form of a sleeve of flexible material, with flex sensors positioned on one or more sides of the sleeve.

[0098] In another alternative example, which is not illustrated but will be described with reference to the knee brace 500, the upper strut 504-1 and lower strut 504-2 may be substantially rigid, but configured to pivot in the frontal plane relative to central portion 502. One or more angle sensors may be provided to measure the relative angle between the upper strut 504-1 and lower strut 504-2, to enable determination of the angulation of the leg.

[0099] In certain forms of the present technology, a wearable device may be configured to measure at least one characteristic of a joint, or a body part associated with a joint, of a wearer. Referring to FIG. 6, a knee brace 600 includes a central joint assembly 602, a first body mounting portion in the form of upper strut 604-1, and a second body mounting portion in the form of lower strut 604-2.

[0100] In a first example, the joint assembly 602 is a planar mechanism configured to provide three degrees of freedom—for example along the x, y, z axes shown in FIG. 6—with the upper strut 604-1 and lower strut 604-2 locked in rotation to restrict movement between them to planar movement. Such an arrangement may provide a multi-axis or “xyz” stage with body attachment to each side of the stage.

[0101] Relative movement between the limb segments (i.e. the upper leg to which upper strut 604-1 is secured, and lower leg to which the lower strut 604-2 is secured) may be sensed using one or more sensors—for example, hall effect sensors and/or optical sensors. Joint laxity may be determined or inferred from this sensed movement.

[0102] In examples, the joint assembly 602 may be configured to selectively restrict movement to less than all degrees of freedom. For example, valgus rotation in the joint assembly 602 may be restricted (i.e. only sagittal plane motion possible), and the rotation locked through a pin mechanism so only relative planar movement of the knee can be sensed.

[0103] In a second example, the joint assembly 602 may include at least three linear joints having a three-axis orthogonal arrangement, each linear joint having an associated sensor configured to output an indication of movement in the associated linear joint (i.e. along a particular orthogonal axis).

[0104] Referring to FIG. 6-2, the joint assembly 602 illustrated includes a first slider 606-1 and a second slider 606-2, allowing movement in the x-y planes to measure laxity. Pin 608 may be selectively inserted into pin apertures 610-1 to 610-3 to lock rotation of the sliding joints at a desired angle.

[0105] In certain forms of the present technology, motion of a patella 700 of a person may be sensed. A reference sensor 702 is provided on the upper leg 506-1, while a motion parameter sensor unit 704 (for example, including an IMU) is provided on the patella 700. As the patella 700 is manipulated, movement data for motion of the sensor unit 704 relative to the reference sensor 702 is captured in order to enable assessment of characteristics such as laxity.

6.7 Determination of Workload and Monitoring Same

[0106] In certain forms of the present technology, a wearable device may be used to monitor workload of a wearer. In an example, the wearable device may be the first knee brace 200-1 or the second knee brace 200-2 as described above, in which knee angle travelled is monitored and used as an indicator of workload. It will be appreciated that the various processing steps described herein may be performed by one or more of at least: dedicated processor(s) of the knee brace 200, processor(s) of user devices 106, and/or the remote processing service 110.

[0107] FIG. 8 illustrates a method 800 of monitoring workload on a user—more particularly monitoring of an acute:chronic workload ratio (ACWR) for the wearer. In a first step 802, the angle of rotation of the knee to which the knee brace 200 is attached is received. In a second step 804, acute workload (for example, accumulated angle of rotation over a 24-hour period) for the wearer is determined. In a third step 806, chronic workload (for example, average daily accumulated angle of rotation over a one-week period) for the wearer is determined. In a fourth step 808, a current ACWR for the wearer is determined based on the acute workload and chronic workload.

[0108] In a fifth step 810, the current ACRW is compared with one or more predetermined thresholds for the user to assess a relative risk of injury or hampering recovery. For example, a first threshold of about 1 may be associated with a cautionary risk level, a second threshold of about 1.5 may be associated with a warning risk level, and a third threshold of about 2 may be associated with an alert risk level.

[0109] In examples, the predetermined thresholds may be time adjusted. Exemplary thresholds for an ACRW of “current day workload: past 7 day moving average workload” are provided in the table below:

TABLE-US-00001 Time since surgery Optimal ACWR Cautionary Warning Alert <1 month 1.0-1.1 1.1-1.2 1.2-1.3 >1.5 1-3 1.0-1.2 1.2-1.5 1.5-1.8 >2.0 3-6 1.0-1.3 1.3-1.7 1.7-2.0 >2.5  9-12 1.0-1.5 1.5-2.0 2.0-2.5 >3.0

[0110] In a sixth step 812, if the current ACRW meets a predetermined threshold, at least one notification may be issued to the wearer, and/or a clinician or trainer of the wearer. In examples, the notification may be issued to a user device 106 (for example in a dedicated application, or as an electronic message). In examples, the notification may be issued at the knee brace 200—for example, a warning light, audible tone, or haptic feedback. In examples, the notification may include recommendations associated with the predetermined threshold—for example advice regarding managing the current workload experienced by the wearer.

[0111] Examples of notifications based on ACWR of “current day workload: past 7 day moving average workload” in the form of electronic messages are provided in the table below:

TABLE-US-00002 ACWR threshold level Timing ACWR: Joint Angle ACWR: Step count Optimal At end of day “Good job, training “Good job, you did the perfect performed well today!” number of steps today!” Cautionary At end of day “You went a little hard “You went a little hard today, today, take it a bit easier take a few less steps tomorrow” tomorrow” Warning As soon as “You are pushing yourself “You are doing too much ACWR hits this too hard, please reduce walking, please minimise steps threshold exercise for the remainder for the remainder of the day” of the day” Alert As soon as “Alert, you are in danger of “Alert, you are in danger of ACWR hits this over exertion and are at over exertion and are at risk of threshold risk of doing damage!” doing damage!”

[0112] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”.

[0113] The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

[0114] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

[0115] Aspects of the present technology may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0116] Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

[0117] It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present technology.