GB2556888A

GB2556888A - Smart apparel

Info

Publication number: GB2556888A
Application number: GB1619784.0A
Authority: GB
Inventors: Llma Marikkar Fatima
Original assignee: Mas Innovation Pvt Ltd
Current assignee: Mas Innovation Pvt Ltd
Priority date: 2016-11-23
Filing date: 2016-11-23
Publication date: 2018-06-13
Also published as: GB201619784D0

Abstract

A system for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user has a first sensor arrangement 14 incorporated within at least one garment which is configured to detect at least one biomechanical parameter relating to the angle of at least one ankle joint of the user. Alternatively or in addition the system has a second sensor arrangement 16 configured to detect at least one biomechanical parameter relating to the motion of the pelvis of the user. The system also includes a processing unit 20 which is configured to receive information on the biomechanical parameters, to calculate a performance metric, and to provide performance-related feedback to the user. The system may detect the orientation of a foot of a user; the activity may be cycling, swimming or a resistance exercise.

Description

(71) Applicant(s):

MAS Innovation (PVT) Limited 10th Floor, Aitken Spence Tower 11,

315 Vauxhall Street, Colombo, 02, Sri Lanka (72) Inventor(s):

(56) Documents Cited:

GB 2377157 A US 20100137749 A1 US 20060217233 A1 (58) Field of Search:

INT CLA41D, A61B, A63B Other: EPODOC WPI

Fatima Lima Marikkar

US 5610528 A US 20070275830 A1 US 20030083596 A1 (74) Agent and/or Address for Service:

Coller IP Management Limited

Fugro House, Hithercroft Road, Wallingford,

Oxfordshire, 0X10 9RB, United Kingdom (54) Title of the Invention: Smart apparel

Abstract Title: System for monitoring movement of lower body while undertaking physical activity (57) A system for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user has a first sensor arrangement 14 incorporated within at least one garment which is configured to detect at least one biomechanical parameter relating to the angle of at least one ankle joint of the user. Alternatively or in addition the system has a second sensor arrangement 16 configured to detect at least one biomechanical parameter relating to the motion of the pelvis of the user. The system also includes a processing unit 20 which is configured to receive information on the biomechanical parameters, to calculate a performance metric, and to provide performance-related feedback to the user. The system may detect the orientation of a foot of a user; the activity may be cycling, swimming or a resistance exercise.

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Figure 1

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Figure 2

202

Smart apparel

This invention relates to systems and methods for monitoring cyclical movements of the lower body of a user undertaking a physical activity, such as cycling or swimming, and for providing performance-related feedback to the user.

Fitness is a focus by many due to the growing trend of wanting to look and feel good. With increased stress levels as a result of the hectic lifestyle of today, access being made easier and participation possible, many are participating in different sports. And the number of participants in sport from leisure to serious is ever increasing. They desire to beat their best and constantly improve fulfilling the human need of achievement.

Recreational participants in sports, such as swimming and cycling, are increasingly turning to technological solutions to gather information and metrics relating to their performance during training sessions. These solutions may be used during a training session so that the user understands the intensity of their training and may also be used to build up a record of training over a period of time, for example by uploading gathered data to a fitness app.

One such technological solution is a smart watch or activity tracker which is typically worn on the wrist of the user and may be used, for example, to track distance travelled, heart rate and other physiological data. Waterproof smartwatches have been developed with swimming-specific modes, for example the Garmin Swim™ which can track the distance covered (if pool length data is entered), the number of strokes made, and the stroke type amongst other metrics.

Activity trackers have also been developed to gather cycling-specific metrics. For example the Moov Now™ is a wearable technology that may be worn on a strap around the leg and provides gross measures of performance including cycling cadence, heart rate, speeds reached, distance travelled etc. This type of technology can be used alone or in combination with a pedal or crank power meter to help the user link such metrics to the levels of crank power generation.

Smart clothing solutions have also been developed to help the user understand their training with in built sensors to detect physiological parameters, and in some cases body motions. For example, the Hexoskin™ clothing range monitors, amongst other metrics, heart rate, heart rate variability, heart rate recovery, breathing rate and minute ventilation (L/min). This data can be uploaded to fitness apps and therefore combined with GPS data to provide the user with an overview of their training session.

Such inventions have enabled recreational athletes to gain greater understanding of gross measures of performance such as distance travelled, speeds reached, levels of power generation, and to understand their physiological response to the intensity of a particular training session. Yet whilst these measurements allow athletes to further understand their performance, the gathered metrics are not so useful for the user to help understand howto subsequently improve their performance, in particular through enhanced technique.

Cycling movements ofthe lower body, which are characterised by a repeating pattern of movement, with no fixed start and finish, are an important component of a number of sports, including cycling, swimming, and a plethora of resistance exercises.

Cyclical movements are typically bi-lateral, with the movements of two limbs occurring symmetrically. These movements can be described as synchronouslysymmetrical and asynchronously-symmetrical; where the former movements are comprised of symmetrical movements of both limbs performed synchronously, whilst the latter movements comprised of symmetrical movements performed by both limbs asynchronously, typically overlapping with one cycle starting for a given limb as the other limb is halfway through the same cycle.

Cyclical movements ofthe legs are initiated at the pelvis and hip, resulting in consequential movements ofthe thigh, knee, shank, ankle and foot. The combination of these inter-connected segments can be described as a kinetic chain, with the movement of one segment having a net reaction on the other segments in said chain. The combination of these individual segmental and joint rotations throughout the kinetic chain, results in the exertion of a force by the leg and/or foot onto either a piece of equipment or the surrounding environment. These forces can be used to either move a piece of external equipment, or to produce a force in a given direction and to propel the body in the opposite direction.

In bicycling, the cyclical movement ofthe legs results in the exertion of a force onto a pedal, resulting in a rotation of a crank, and further resulting in a rotation of a connected wheel. In swimming and resistance exercises, a force is exerted against the surrounding environment to produce a movement in the direction opposite to the direction ofthe applied force. In swimming this force is exerted against the water, propelling the swimmer horizontally; whereas in resistance exercises such as squatting, the force results in an extension of the leg, forcing the trunk and pelvis away from the site of force application.

The magnitude and direction of the forces applied are the result of the collective segmental and joint rotations; therefore, understanding such rotations is of great interest.

Systems are known which utilise sensors attached to a user in order to understand motion during a physical activity. For example, US8845494B2 describes a system for providing feedback on walking technique. This system uses accelerometry data to identify key gait events to measure temporal and spatial gait parameters such as step length and step rate. This system is however unsuitable and insufficient for measuring the biomechanical parameters which the applicants propose are key to understanding cyclical movements of the lower body, and therefore unsuitable for understanding how a user’s lower body cyclical movements could be modified in order to enhance user performance.

There remains a need to provide systems for use by athletes, such as swimmers and cyclists, which capture metrics which enable feedback to be provided which moves beyond the athlete simply understanding their performance, to providing an enhanced understanding of how the user may improve performance, in particular through enhanced technique.

Accordingly, in a first aspect of the invention there is provided a system for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user, the system comprising a first sensor arrangement incorporated within at least one garment and configured to detect at least one biomechanical parameter relating to the angle of at least one ankle joint of the user. Preferably, the first sensor arrangement comprises: (i) at least one stretch sensor which, in use, is positioned at the back of the ankle joint; or (ii) a plurality of sensors which, in use, are positioned adjacent to a shank and adjacent to a foot of the user, enabling the at least one ankle joint angle parameter to be measured. Alternatively, or in addition, the system comprises a second sensor arrangement configured to detect at least one biomechanical parameter relating to the motion of the pelvis of the user, in particular the angle and I or orientation of the pelvis. The first and I or the second sensor arrangements are additionally configured to detect performance parameter information during the physical activity. The system also comprises a processing unit configured to receive information on the at least one biomechanical parameter from the first sensor arrangement and / or the second sensor arrangement, to use the performance parameter information to calculate a performance metric, and to provide performance-related feedback to the user.

The system of the invention utilises sensors, such as fabric I textile sensors, to directly measure limb and joint angles, rotations and movements. The placement of sensor arrangements at the ankle joint, the most distal joint of the kinetic chain, and / or the pelvis, the most proximal aspect of the kinetic chain, enables the user to receive feedback on cyclical movements of the lower body which are key to performance in a number of physical activities, in particular cycling and swimming. In addition, the proposed sensor placements advantageously enable the measurement of key performance parameter information which can be used to calculate performance metrics.

The combination of the measurement of key kinematic variables relating to cyclical movements and performance metrics enables the provision of enhanced feedback to the user. For example in the case of cycling, an understanding of the interdependence between pedalling kinematics, such as ankle angle parameters, and kinetics, such as pedalling cadence, an athlete can be better informed as to how to improve their pedalling technique, to maximise force transfer to the pedal and therefore improve the efficiency and force effectiveness. Based on this feedback, the user can be provided with guidance to improve their technique leading to an improvement in their cycling performance.

The combined measurement of the orientation and movements of the ankle joint and the pelvis enable an enhanced understanding of the lower limb kinetic chain from both the proximal and distal ends of said chain, and enables the provision of biomechanical information of particular importance to the analysis of lower limb movements, and for the performance of the user, enabling enhanced performance-related feedback to be provided to the user.

The system is configured to monitor cyclical movements of the lower body, i.e. repeating movements of the lower limbs initiated by a movement of the hip or pelvis culminating in the movement of the foot and I or ankle, for example the movement of the lower limbs whilst the user is cycling or the movement of the lower limbs during a repeating swimming stroke. The first sensor arrangement is configured to detect at least one parameter relating to the ankle joint angle of the user. Preferably the first sensor arrangement is configured to measure the angle of the ankle joint in all three planes of motion. The first sensor arrangement is configured to measure, for example, at least one of the maximum and / or minimum ankle angle during a cyclical movement in each plane, the range of motion ofthe ankle joint during a cyclical movement (the difference between maximum and minimum values) in each plane and the time of maximal or minimal ankle angle during a cyclical movement. These parameters are proposed to be of key importance to understanding technique across a number of physical activities, in particular cycling.

Preferably, the physical activity is cycling and the sensor first arrangement is configured to measure the range of motion ofthe ankle joint during a cyclical movement and I or the ankle plantarflexion during a cyclical movement. The parameters are proposed as key parameters for pedalling efficiency and I or effectiveness.

The first sensor arrangement is incorporated within a garment which is close fitting to the body ofthe user, such as an ankle sleeve, sock or tights, and preferably comprises a fabric sensor. Incorporation of sensor arrangements into garments worn by the user has been found to facilitate reproducible data collection and is convenient for the user. The first sensor arrangement may comprise at least one stretch sensor, for example a stretch sensor which, in use, is positioned at the back of the ankle joint, preferably in the direction of the Achilles tendon. Preferably the first sensor arrangement comprises a plurality of stretch sensors configured to measure ankle joint angle parameters in three planes of motion. This provides an unobtrusive sensor arrangement which enables accurate measurement of ankle joint angle parameters. As an alternative the first sensor arrangement may comprise a plurality of sensors which, in use, are positioned adjacent to a shank and adjacent to a foot of the user, enabling the at least one ankle joint angle parameter to be measured.

Preferably, the system measures ankle joint parameters for both ankles ofthe user.

It will be understood that the first garment could therefore be a single garment configured to measure parameters relating to both ankles, for example a pair of cycling tights, ora pair of garments configured to measure parameters relating to both ankles, for example a pair of socks or ankle sleeves. This allows for asymmetries in movement to be detected and more refined analysis of technique to be performed.

The second sensor arrangement is configured to detect at least one parameter relating to the motion ofthe pelvis ofthe user, such as relating to pelvic stability, and pelvic orientation and position, for example the anterior-posterior orientation ofthe pelvis, the medio-lateral orientation ofthe pelvis, the axial orientation ofthe pelvis, the anteriorposterior rotation ofthe pelvis, the medio-lateral rotation ofthe pelvis, the axial rotation of the pelvis, the anterior-posterior movement of the pelvis, the medio-lateral movement of the pelvis or the axial movement of the pelvis.

Preferably, the second sensor arrangement is configured to measure at least one of the axial rotation of the pelvis, the medio-lateral rotation of the pelvis and the medio-lateral movement of the pelvis, which provide key information on pelvic stability. The second sensor arrangement may comprise, for example, an accelerometer and a gyroscope, such as an inertial motion unit (IMU).

Preferably the system measures a combination of the range of motion of the ankle joint during the cyclical movement or ankle plantar flexion, and one or more of the axial rotation of the pelvis, the medio-lateral rotation of the pelvis and the medio-lateral movement of the pelvis.

It has been found that in use the second sensor arrangement is ideally placed close to the pelvic region. Preferably, the second sensor arrangement is also be incorporated into a garment worn by the user, for example incorporated into a pair of shorts, a cycling bib, a swimming costume, or the like. It will be understood that the first and second sensor arrangements may be incorporated into a single garment worn by the user.

The first and second sensor arrangements are configured to collect biomechanical data and transmit this data to a processing unit. The sensors may be connected to the processing unit via, for example, data transmission paths embedded in a garment or may be connected wirelessly.

The first and I or the second sensor arrangements are additionally configured to detect performance parameter information during the physical activity which can be used to calculate a performance metric, for example forward velocity, pedal cadence, etc.

In the case that the physical activity is swimming, preferably the second sensor arrangement is configured to detect performance parameter information from which the forward horizontal velocity of the pelvis may be calculated, preferably the minimum forward horizontal velocity of the pelvis during a cyclical movement. This enables the user to be able to understand how the configuration and movement of the lower limbs affects the resultant forward horizontal velocity.

In the case that the physical activity is cycling, preferably the first sensor arrangement is configured to detect performance parameter information from which the pedal cadence may be calculated. For example using the cyclical, repeating pattern of a given output, such as the ankle angle in the sagittal plane, an event in the cycle can be identified, such as a maximum or minimum angle. The time between successive events can be understood to be a full cycle, and therefore cadence can be identified as the number of cycles per minute. This enables the user to be able to understand how the configuration and movement of the lower limbs affects the crank rotation rate, and from which velocity may be calculated.

The processing unit is configured to receive information on the at least one biomechanical parameter from the first sensor arrangement and I or the second sensor arrangement; to use the performance parameter information to calculate a performance parameter, and to provide performance-related feedback to the user. It will be understood that the processing unit may utilise individual data points or may analyse data relating to the mean (or other average) value over a series of cyclical motions and I or the variability over a time period or variability between individual limbs.

The processing unit may be configured to compare the at least one biomechanical parameter with a model of the physical activity. The model typically comprises information on plurality of variables relating to the cyclical movements of the lower body of a user undertaking the physical activity, such as swimming or cycling, for example comprising information relating to optimal ranges for each of the plurality of variables. Preferably the variables are selected and I or the optimal ranges generated by an analysis of the motion and performance of a plurality of individuals undertaking the physical activity. More preferably, the variables are selected and I or the optimal ranges are generated by an analysis of the motion of at least two groups of individuals with different performance levels, e.g. beginner and expert levels.

The optimal range may be adjusted, for example, based on personal data entered by the user, for example relating to age, sex, height, weight etc. This range may also be adjusted based on contextual data, such as data collected over the period of the physical activity. In the case where the data received is outside of an optimal range, the processing unit is configured to decide whether a feedback response should be provided .

The processing unit is configured to provide performance-related feedback to the user. Preferably the feedback comprises information on biomechanical and performance parameters, for example relating to changes in a measured biomechanical parameter in the context of a calculated performance parameter. Feedback may be provided by, for example, an audio speaker or visual display.

Preferably, this feedback is provided during the physical activity. This feedback may include the use of mechanical stimulus, for example by at least one actuator. Preferably the actuator is one or more of haptic actuator, thermal actuator, peltier tiles, transcutaneous electrical nerve stimulation (TENS) actuator, electro-active polymer or micro-piezo actuator, for example by at least one haptic actuator.

The means for providing a mechanical stimulus, such as at least one haptic actuator, may be embedded in one or more garments forming part of the system. The means for providing a mechanical stimulus, such as a haptic actuator, may be positioned to provide a feedback response at the location of the body at which a correction of technique is required, thereby enhancing the effectiveness of the feedback and helps the wearer to distinguish the action needed by them.

The feedback may also be by audio or visual means, for example through at least one speaker, headphones worn by the user and / or a visual display, etc. The system may be configurable to allow the user to customise the feedback response, for example, enabling the selection of the means of feedback response. The system may use both mechanical and audio feedback mechanisms, for example through the combination of one or more haptic actuators and an audio and / or visual feedback mechanism.

The system may also be configured to enable the user to review analytical data relating to the physical activity. For example, during or after the physical activity data may be transferred to a software application, which may be configured to enable, for example, visualisation of post-activity analytics, a comparison with historical data etc.

Preferably, the system additionally comprises a sensor arrangement configured to detect at least one parameter relating to a shank angle ofthe user with respect to gravity, preferably in all three planes of motion. The use of a sensor arrangement to measure shank angle is beneficial, in particular for cycling in which knowledge ofthe angle ofthe shank with relation to crank position enables understanding and calculation of a wide range of metrics including the calculation of knee joint kinetics including joint moments, powers and work done. This sensor arrangement is preferably embedded in a garment worn by the user, and may, for example be an IMU, which is configured such that, in use, the sensor arrangement is positioned anteriorly on the tibia. Preferably, the system comprises sensor arrangements configured to measure parameters relating to the both shank angles ofthe user.

The sensor arrangement may measure, for example, the angle of shank in a given plane with respect to gravity, the range of shank motion in a given plane with respect to gravity during a cyclical movement, the maximum angular acceleration ofthe shank during a cyclical movement, the change in angular velocity of the shank during a cyclical movement. It will be understood that the system may measure such parameters for one shank, or both shanks, and preferably analyses the difference between the parameters measured for the left and right shank. In the case where the physical activity is cycling, the above described parameters, such as the angle ofthe shank in a given plane or the range of shank motion in a given plane, may preferably be measured with respect to the bicycle crank angle.

Preferably, the system additionally comprises a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot of the user with respect to gravity, preferably in all three planes of motion. Preferably, the system comprises sensor arrangements configured to measure parameters relating to the angle of both feet of the user. The use of a sensor arrangement to analyse foot orientation is beneficial, in particular for cycling in which knowledge ofthe angle ofthe foot with relation to crank position enables understanding and calculation of a wide range of metrics including the calculation of ankle joint kinetics including joint moments, powers and work done. The foot is the most distal aspect of the kinetic chain, and is responsible for the force transfer onto the pedal and consequentially the crank, turning the back wheel. The angle ofthe foot, sagittally helps develop the user’s understanding of how to manipulate and improve efficiency of force transfer to the crank.

Preferably, the system comprises a sensor arrangement configured to detect at least one parameter relating to a shank angle of the user with respect to gravity, preferably in all three planes of motion, for example an IMU; and at least one stretch sensor which, in use, is positioned at the back of the ankle joint, preferably a plurality of stretch sensors configured to measure ankle joint angle parameters in three planes of motion. This combination of sensor arrangements enables the measurement of the orientation ofthe foot without the presence of a sensor positioned in use adjacent to the foot which may be uncomfortable for the user. Preferably the system comprises a garment incorporating (i) at least one stretch sensor embedded in the garment which, in use, is positioned at the back ofthe ankle joint, preferably a plurality of stretch sensors embedded in the garment configured to measure ankle joint angle parameters in three planes of motion; and (ii) a sensor arrangement embedded within the garment which is configured to detect at least one parameter relating to a shank angle ofthe user with respect to gravity, preferably in all three planes of motion, for example an IMU.

As an alternative, the sensor arrangement may preferably be configured such that in use, the sensor arrangement is positioned on top of the foot along the metatarsal or on a lateral aspect of the foot along the metatarsal. This sensor arrangement is preferably embedded in a garment worn by the user and may for example comprise an IMU.

The sensor arrangement may measure, for example, the angle of foot in a given plane with respect to gravity, the range of foot motion in a given plane with respect to gravity during a cyclical movement, the maximum angular acceleration ofthe foot during a cyclical movement, the change in angular velocity ofthe foot during a cyclical movement. It will be understood that the system may measure such parameters for one foot, or both feet, and preferably analyses the difference between the parameters measured for the left and right foot.

In the case where the physical activity is cycling, the above described parameters, such as the orientation ofthe foot and the range of foot motion in a given plane, may preferably be measured with respect to the bicycle crank angle.

In the case where the physical activity is cycling, the sensor arrangement may preferably measure the range of foot motion in a given plane with respect to the bicycle crank.

In a preferred embodiment ofthe system, the system comprises a first sensor arrangement as described herein and a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot ofthe user with respect to gravity, preferably in all three planes of motion, enabling analysis of foot and ankle kinematics.

Preferably, the system additionally comprises a sensor arrangement configured to detect at least one parameter relating to a thigh angle ofthe user with respect to gravity, preferably in all three planes of motion. The use of a sensor arrangement to measure thigh angle is beneficial, for example it can help to enable the calculation of hip joint kinetics, including joint moments, powers and work done. This sensor arrangement is preferably embedded in a garment worn by the user, and may, for example be an IMU, which is configured such that in use, the sensor arrangement is positioned laterally on the iliotibial band, between the quadriceps and hamstrings. Preferably, the system comprises sensor arrangements configured to measure parameters relating to the both thigh angles ofthe user.

The sensor arrangement may measure, for example, the angle of the thigh in a given plane with respect to gravity, the range of thigh motion in a given plane with respect to gravity, the maximum angular acceleration of the thigh, the change in angular velocity of the thigh. It will be understood that the system may measure such parameters for one thigh, or both thighs, and preferably analyses the difference between the parameters measured for the left and right thigh.

In the case where the physical activity is cycling, the above described parameters, such as the thigh angle and range of thigh motion in a given plane, may preferably be measured with respect to the bicycle crank angle.

The sensor arrangements which in use may be positioned at the shank, foot and / or thigh, have the potential to measure each ofthe following parameters (in all three planes) relating to the adjacent section (shank, foot or thigh): the angle, the angle range of motion, the minimum and I or maximum angle, the mean angle over a number of cyclical movements, the angular velocity, the change in angular velocity, the minimum and I or maximum angular velocity.

In a preferred embodiment ofthe system ofthe invention, the system comprises the second sensor arrangement as described herein, in combination with a sensor arrangement configured to detect at least one parameter relating to a thigh angle ofthe user with respect to gravity, preferably in all three planes of motion. The two sensor arrangements may be incorporated within a garment. This embodiment is especially advantageous if the physical activity is swimming, for example enabling the identification of swimming strokes and providing associated feedback. Preferably the system is configured to measure the vertical oscillation of the pelvis.

In a further preferred embodiment of the system of the invention, the system comprises the first and second sensor arrangements as described herein, in combination with a sensor arrangement configured to configured to detect at least one parameter relating to a thigh angle of the user with respect to gravity as described herein; and a further sensor arrangement configured to detect at least one parameter relating to a shank angle of the user with respect to gravity as described herein.

In another preferred embodiment of the system of the invention, the system comprises a first sensor arrangement comprising a plurality of sensors which, in use, are positioned adjacent to a shank and adjacent to a foot of the user as described herein, in combination with a sensor arrangement configured to configured to detect at least one parameter relating to a thigh angle of the user with respect to gravity as described herein.

Preferably, the system additionally comprises a sensor arrangement configured to detect at least one parameter relating to a knee joint angle of the user. Preferably the sensor arrangement is configured to measure knee joint angle in all three planes of motion. The use of a sensor arrangement to measure knee joint angle can provide an enhanced understanding of the movement of the lower limbs during the cyclical movement, in particular understanding of the range of motion of the knee provides an enhanced understanding of lower limb configuration throughout the cyclical movement. Understanding of knee joint movement helps to develop the understanding of the movement of the kinetic chain as a whole, with the largest ranges of movement being observed at the knee joint.

This sensor arrangement is preferably embedded in a garment worn by the user and may, for example, comprise at least one stretch sensor. The sensor arrangement may be configured such that, in use, at least one stretch sensor is placed across the patella, in the direction of the patella tendon. Preferably the sensor arrangement comprises a plurality of stretch sensors configured to measure ankle joint angle parameters in three planes of motion. Preferably, the system comprises sensor arrangements configured to measure parameters relating to both knee joints of the user.

The sensor arrangement may measure, for example, the minimum knee extension during a cyclical movement, the maximum knee extension during a cyclical movement, the maximum knee flexion during a cyclical movement, the maximum knee abduction during a cyclical movement, the maximum knee adduction during a cyclical movement, the maximum internal knee rotation during a cyclical movement, the maximum external knee rotation during a cyclical movement, the flexion-extension range of motion of the knee during a cyclical movement, the abduction-adduction range of motion of the knee during a cyclical movement, the internal-external rotation range of motion of the knee during a cyclical movement, the angular velocity of the knee during a cyclical movement (such as the maximum or minimum angular velocity), the angular acceleration of the knee during a cyclical movement (such as the maximum or minimum angular acceleration), the change in angular velocity of the knee during a cyclical movement. It will be understood that the system may measure such parameters for one knee, or both knees, and may analyse the difference between the parameters measured for the left and right knee.

Preferably, the sensor arrangement measures at least one of: the maximum knee extension, the maximum knee flexion, the flexion-extension range of motion of the knee, the angular velocity of the knee, maximum angular acceleration of the knee and the change in angular velocity of the knee.

Preferably, the system additionally comprises a sensor arrangement configured to detect at least one parameter relating to a hip joint angle of the user. Preferably the sensor arrangement is configured to measure hip joint angle in all three planes of motion. The use of a sensor arrangement to measure hip joint angle can provide an enhanced understanding of the movement of the lower limbs during the cyclical motion The hip joint is the most proximal joint in the kinetic chain, and is the joint responsible for initiating the movement of the kinetic chain of the leg. Understanding the movement of the hip joint helps to develop the understanding of the kinetic chain as a whole. This sensor arrangement is preferably embedded in a garment worn by the user. The sensor arrangement measures the difference in orientation between the pelvis and the hip which may be measured, for example, by a sensor directly measuring the angle between the two segments, or by sensors measuring the orientation of each segment. Preferably, the system comprises sensor arrangements configured to measure parameters relating to both hip joints of the user.

The sensor arrangement may measure, for example, the maximum hip extension during a cyclical movement, the maximum hip flexion during a cyclical movement, the maximum hip abduction during a cyclical movement, the maximum hip adduction during a cyclical movement, the maximum internal hip rotation during a cyclical movement, the maximum external hip rotation during a cyclical movement, the flexion-extension range of motion of the hip during a cyclical movement, the abduction-adduction range of motion of the hip during a cyclical movement, the internal-external rotation range of motion of the hip during a cyclical movement, the angular velocity of the hip during a cyclical movement, the maximum angular acceleration of the hip during a cyclical movement, the change in angular velocity of the hip during a cyclical movement. It will be understood that the system may measure such parameters for one hip, or both hips, and preferably analyses the difference between the parameters measured for the left and right hip.

Preferably, the system measures at least one of: the maximum hip extension, the maximum hip flexion, the flexion-extension range of motion of the hip, the angular velocity of the hip, the maximum angular acceleration of the hip, the change in angular velocity of the hip.

In a preferred embodiment of the system of the invention, the system comprises the second sensor arrangement as described herein in combination with a sensor arrangement configured to detect at least one parameter relating to a hip joint angle of the user.

In a further preferred embodiment of the invention, the system comprises a first sensor arrangement as described herein, in combination with a sensor arrangement configured to detect at least one parameter relating to a hip joint angle of the user and a sensor arrangement configured to detect at least one parameter relating to a knee joint angle of the user.

It will be understood that each parameter described herein may be measured over the course of a single cyclical movement, or may be measured over a multiplicity of cyclical movements and, for example, the average value assessed. It will also be understood that the sensor arrangements are configured to measure, for example, at least one of the maximum and I or minimum angle during the cyclical movement in each plane; the range of motion (the difference between maximum and minimum values) in each plane; the time of maximal or minimal angle during a cyclical movement. Furthermore, each parameter described herein may be measured during a particular section or phase of the movement, over the course of a single cyclical movement or over the course of a multiplicity of cyclical movements.

In addition, it will be understood that the sensor arrangements as described herein may also be used to measure at least one parameter relating to the linear movement of each limb, such as the linear movement of the foot, shank and I or thigh, for example the linear displacement, linear velocity and linear acceleration of each limb in all three planes, as well as maximum, minimum, range of motion and average of each of these metrics, in absolute terms, or during a given phase of the cyclical movement.

In the case that the physical activity is cycling, the parameter may be measured over a crank cycle (a rotation of the pedal from top vertical, round back to top vertical), or over a phase of a crank cycle.

The system may be additionally configured to receive data from an external power meter, such as a power meter incorporated into a piece of exercise equipment, such as a footplate, or a garment such as a shoe. It will be understood that the term power meter as used herein includes a force meter, which measures force from which power can be derived. In one embodiment of the invention, the physical activity is cycling and external power meter is incorporated into a bicycle, such as a pedal or crank power meter. It will be understood by the skilled person that the system may also be configured to receive data from alternative devices that provide a force measurement explicitly or as a function of a variable from which force could be derived, such as a device measuring pressure.

In the case of cycling, the aim of the combined movements of the individual segments and joints of the legs is to produce a force at the foot, which is applied bi-laterally to the pedals. Therefore the system of the invention enables the provision of information which is useful for the user to be able to understand how the configuration and movement of the lower limbs affects resultant applied forces, which may be measured externally at the pedal or crank.

In cases wherein the system of the invention comprises a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot of the user with respect to gravity, the data from the external power meter may be used by the system to analyse ankle joint force during a cyclical movement, preferably in the three planes of the ankle movement. Such measurements of foot orientation and movement, in combination with an external measure of applied force, facilitate the measurement of kinetic parameters at the ankle joint, which allow for more detailed analysis of the turning forces generated at the ankle joint, and thus insights into the work performed by the dorsi and plantar flexors of the ankle joint. The system may therefore also be configured to use joint force values to calculate the ankle joint moment and I or the ankle joint power and I or the ankle joint work done.

In cases wherein the system ofthe invention comprises a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot ofthe user with respect to gravity and a sensor arrangement configured to detect at least one parameter relating a shank angle of the user with respect to gravity, the data from the external power meter may be used by the system to analyse the knee joint force, preferably in the three planes of the knee movement. Measurements of shank orientation and movement in combination with previously calculated ankle joint forces facilitate the measurement of kinetic parameters at the knee joint, which allow for more detailed analysis of the turning forces generated at the knee joint, and thus insights into the work performed by the flexors and extensors of the knee joint. The system may therefore also be configured to use joint force values to calculate the knee joint moment and I or the knee joint power and I or the knee joint work done.

In cases wherein the system ofthe invention comprises a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot ofthe user with respect to gravity, a sensor arrangement configured to detect at least one parameter relating a shank angle ofthe user with respect to gravity and a sensor arrangement configured to detect at least one parameter relating to the thigh angle ofthe user with respect to gravity, the data from the external power meter may be used by the system to analyse the hip joint force. Measurements of thigh orientation and movement in combination with previously calculated ankle and knee joint forces facilitate the measurement of kinetic parameters at the hip joint, which allow for more detailed analysis ofthe turning forces generated at the hip joint, and thus insights into the work performed by the flexors and extensors ofthe hip joint. In combination with the kinetic analysis ofthe ankle and knee joints, estimations of power leakage across the kinetic chain can be estimated. Therefore, the system may also be configured to use joint force values to calculate the hip joint moment and I or the hip joint power and I or the hip joint work done.

The system ofthe invention may be advantageously configured to additionally capture and utilise other metrics relating to performance in a given activity.

For example in the case that the physical activity is cycling the system may capture data such as: pedal cadence (revolutions per minute), distance travelled, crank rotation velocity and distance travelled per pedal cycle.

In the case that the physically activity is swimming the system may capture velocity data, for example changes in the forward horizontal velocity of the pelvis. It will be understood that such parameters may be measured directly by the system, or the system may receive data from external device. For example in the case of distance travelled, information relating to this parameter may be received from a GPS device, or may be calculated from measured acceleration data. Such metrics may, for example, be used to provide context to the feedback provided by the system, or may be utilised in algorithms used by the system to provide feedback to the user.

In a second aspect of the invention there is provided a garment, such as a sock or tights, comprising (i) at least one stretch sensor embedded in the garment which, in use, is positioned at the back of the ankle joint, preferably a plurality of stretch sensors embedded in the garment configured to measure ankle joint angle parameters in three planes of motion; and (ii) a sensor arrangement embedded within the garment which is configured to detect at least one parameter relating to a shank angle of the user with respect to gravity, preferably in all three planes of motion, for example an IMU.

In a third aspect of the invention there is provided a method for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user using a system as described herein, the method comprising:

sensing at least one biomechanical parameter relating to the angle of at least one ankle joint of the user; and I or at least one biomechanical parameter relating to the motion of the pelvis of the user; sensing performance parameter information; using the performance parameter information to calculate a performance parameter; providing performance-related feedback to the user.

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic drawing of an embodiment of the system of the invention with two sensor arrangements.

Figure 2 shows a schematic drawing of an embodiment of the system of the invention with seven sensor arrangements.

Definitions

Ankle joint angle - Angle between the foot and shank

Knee joint ankle - Angle between the shank and thigh

Hip joint angle - Angle between the thigh and pelvis

Foot angle - Orientation of foot segment with respect to gravity

Shank angle - Orientation of shank segment with respect to gravity

Thigh angle - Orientation of thigh segment with respect to gravity

Pelvis angle - Orientation of pelvis segment with respect to gravity

Ankle plantar flexion/dorsi flexion - Angle between the foot and shank, whereby the dorsal surface of the foot is rotated away from the anterior surface of the shank; and whereby the dorsal surface of the foot is rotated towards from the anterior surface of the shank.

Knee flexion/extension - Angle between the shank and thigh, whereby the shank is rotated towards the thigh; and whereby the shank is rotated away from the thigh towards vertical alignment of the thigh and shank.

Hip flexion/extension - Angle between the thigh and pelvis, whereby the thigh is rotated anteriorly; and whereby the thigh is rotated posteriorly, with respect to the pelvis.

Range of Motion - The difference between minimum and maximum values for a given metric.

Description of embodiments of the invention

Figure 1 shows a system 10 for monitoring cyclical movements of the lower body of a user who is riding a bicycle. The system 10 includes a pairof tights 12 worn by the user whilst cycling. The tights 12 incorporate a stretch sensor 14 which is embedded in the material of the tights and which in use is positioned down the back of an ankle joint in the direction of the Achilles tendon. The system also includes a module 16 positioned close to the pelvis of the user which is attached to the tights 12 via an interface connector which provides electrical and data connectivity to the sensor 14 via data transmission pathway 18 embedded in the tights 12. The interface connector is additionally configured to hold the module 16 in place, for example via a snap fit connection. The module 16 comprises a inertial motion unit (IMU) and a processing unit. The processing unit is configured to receive information from the stretch sensor 14 and the IMU, to compare the information with a model of cycling motion and to generate feedback to the user. The feedback may be displayed to the user on a smartphone 20 or other portable electronic device, which is connected to the processing module via a wireless data connection, for example a Bluetooth connection. Prior to going fora cycle ride, the user puts on the tights 12 and then connects the module 16. The system 10 then generates data on the cyclical movements on the lower body ofthe user by measuring parameters relating to the ankle angle using the stretch sensor 14 and the motion ofthe pelvis (16) using the IMU. These parameters are then assessed by the processing unit by a comparison ofthe values to a model of cycling motion and the pedal cadence value is calculated by an analysis ofthe ankle stretch sensor 14 data over time. The system then provides feedback to the user. For example the system 10 may detect that the maximum ankle flexion of one ankle joint of the user during each cyclical motion is less than an optimal value for a particular cadence range, and provide instructions to the user as to how they can increase ankle flexion, for example using a verbal prompt delivered from the smartphone 20, and therefore help enhance their cycling technique. In an alternative embodiment ofthe system the stretch sensor 14 is replaced with a inertial measurement unit (IMU) positioned adjacent to the top ofthe foot along the metatarsal 22 and an IMU positioned adjacent to the tibia 24.

Figure 2 shows a second embodiment 200 ofthe system ofthe invention with additional sensor arrangements. Features that are the same as those shown in Figure 1 are provided with the same numbers. The system 200 has two additional stretch sensor arrangements in comparison with system 10 (Figure 1). Firstly, a stretch sensor 202 is embedded in the material ofthe tights 12 so that in use the sensor 202 is positioned across the patella, in the direction ofthe patella tendon. Secondly a stretch sensor 204 is embedded in the material ofthe tights 12 so that in use the sensor 204 is positioned to measure changes in the angle between the pelvis and hip segments. The system 20 also incorporates an IMU sensor 206 placed laterally on the iliotibial band, between the quadriceps and hamstrings, an IMU sensor 208 placed anteriorly on the tibia, and an IMU sensor 210 positioned on top ofthe foot along the metatarsal, which are incorporated within the tights 12. The additional sensor arrangements 202-210 are connected to the module 16 using data transmission paths 18, and provide additional data on the cyclical movement of the lower limbs during the bicycle ride which enhances the ability of the system to provide effective feedback to the user.

It will be understood by the skilled person that one or more of the sensors may be connected by alternative means to the processing module, for example wirelessly. In addition the feedback to the user may be provided by alternative means, for example through haptic feedback provided by one of more actuators embedded in the garment. Furthermore the processing unit may be housed separately from the pelvic IMU sensor, and may be a separate component.

Measurement of parameters and derived variables

The following provides a description of how the systems of the invention may measure the parameters of interest and calculate derived variables:

(a) Orientation of a given limb or segment can be identified using the orientation of a sensor, measured gyroscopically, attached to said limb or segment. It can be expressed in a local co-ordinate/reference system as with respect to another limb or segment, or in the global co-ordinate/reference system with respect to gravity.

(b) Linear movements of a given limb or segment can be identified using the absolute, integrated or differentiated acceleration signals of a sensor attached to said limb or segment to identify jerk, acceleration, velocity and displacement. These metrics can be expressed in a local co-ordinate/reference system as with respect to another limb or segment, or in the global co-ordinate/reference system with respect to gravity.

(c) Rotational movements of a given limb or segment can be identified using the absolute, integrated or differentiated acceleration and gyroscopic signals of a sensor attached to said limb or segment to identify angular jerk, angular acceleration, angular velocity and angular displacement. These metrics can be expressed in a local co-ordinate/reference system as with respect to another limb or segment, or in the global coordinate/reference system with respect to gravity.

(d) Joint angles can be identified as the difference in orientation between two given limbs or segments, creating a resultant angle between the two in three planes. One method of measurement is to measure the difference in orientation of two individual limbs or segments as described in (a), in which a local co-ordinate system is created by either the proximal or distal segment which would be the primary segment, and the angle of the other limb or segment (the secondary segment) is measured with respect to the primary. Typically, but not exclusively, the primary segment would be the most proximal segment to the pelvis. Another method is to use a sensor in which changes in angle between the two limbs or segments alters the voltage expressed which is then converted to a meaningful measurement of joint angle.

(e) Angular joint movements can be identified using the differentiated difference in orientation between two given limbs or segments overtime, to identify angular acceleration, angular velocity, and angular displacement using the measurements of angle as described in (c). Metrics are expressed in a local co-ordinate system as described in (c).

(f) Joint torques are calculated by modelling the body as a series of rigid segments connected by frictionless joints and subsequently solving the Newton-Euler equations of motion performed distal-to proximally. Newton’s laws of linear motion are applied to a given segment incorporating force applied distally, the mass ofthe segment and the linear velocity ofthe segment. These equations require a bi-directional force input from an external source, knowledge of limb or segment orientation as described in claim a, knowledge of linear limb or segment movement as described in claim b, knowledge of rotational limb or segment movement as described in claim c and limb or segment length and inertial properties as measured in absolute terms, or as calculated from gross anthropometric measures such as height and weight. Uni-planar joint moments require bi-directional force measurements, whilst bi-planar or tri-planar joint moments requires tri-directional force measurements. The results ofthe Newtonian equations for laws of linear motion calculate a bi-directional force at the proximal end of a segment, from a known bi-directional force at the distal end of a segment. The results from the Newtonian equations for laws of linear motion are then input into Eulers law of angular momentum to identify joint torque/moment.

(g) Joint powers are calculated as the product of the known joint torque as described in (f); and angular velocity of said joint, as described in (e).

(h) Work done is calculated as the product of the known joint torque as described in (f), and angular displacement of said joint, as described in (d).

The measured and derived parameters are utilised by the system which compares the parameters with a model ofthe physical activity being undertaken by the user which therefore enables feedback to be provided to the user.

Other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features that are already known and which may be used instead of, or in addition to, features described herein. Features that are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features that are described in the context of a single embodiment may also be provided separately or in any suitable subcombination.

It should be noted that the term “comprising” does not exclude other elements or steps, the term “a” or “an” does not exclude a plurality, a single feature may fulfil the functions of several features recited in the claims and reference signs in the claims shall not be construed as limiting the scope of the claims. It should also be noted that the Figures are not necessarily to scale; emphasis instead generally being placed upon illustrating the principles of the present invention.

Claims

1. A system for monitoring cyclical movements of the lower body of a user undertaking a physical activity and providing feedback to the user, the system comprising:

a first sensor arrangement incorporated within at least one garment and configured to detect at least one biomechanical parameter relating to the angle of at least one ankle joint of the user; and I or a second sensor arrangement configured to detect at least one biomechanical parameter relating to the motion of the pelvis of the user; and wherein the first or the second sensor arrangement is configured to detect performance parameter information during the physical activity;

a processing unit configured to receive information on the at least one biomechanical parameter from the first sensor arrangement and I or the second sensor arrangement; to use the performance parameter information to calculate a performance metric, and to provide performance-related feedback to the user.

2. A system according to claim 1 wherein the first sensor arrangement comprises at least one stretch sensor which, in use, is positioned at the back of the ankle joint.

3. A system according to claim 1 wherein the first sensor arrangement comprises a plurality of sensors which, in use, are positioned adjacent to a shank and adjacent to a foot of the user, enabling the at least one ankle joint angle parameter to be measured

4. A system according to claim 1 wherein the second sensor arrangement is incorporated into a garment worn by the user.

5. A system according to claim 1 or claim 2 wherein the first sensor arrangement comprises a plurality of stretch sensors configured to measure at least one ankle joint angle parameter in three planes of motion.

6. A system according to any one of claims 1 to 5 comprising a sensor arrangement configured to detect at least one parameter relating to a knee joint angle of the user.

7. A system according to any one of claims 1 to 6 comprising a sensor arrangement configured to detect at least one parameter relating to a hip joint angle of the user.

8. A system according to any one of claims 1 to 7 comprising a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot of the user with respect to gravity.

9. A system according to any one of claims 1 to 8 comprising a sensor arrangement 5 configured to detect at least one parameter relating a shank angle of the user with respect to gravity.

10. A system according to any one of claims 1 to 9 comprising a sensor arrangement configured to detect at least one parameter relating to the thigh angle of the user with respect to gravity.

10

11. A system according to any one of the preceding claims wherein the physical activity is cycling.

12. A system according to any one of the preceding claims wherein the physical activity is swimming.

13. A system according to any one of the preceding claims wherein the physical activity is a 15 resistance exercise.

14. A system according to any one of the preceding claims wherein the feedback is provided to the user whilst the user is undertaking the physical activity.

15. A system according to any one of the preceding claims in which the system is configured to receive data from an external power meter.

20

16. A system according to claim 15 wherein the physical activity is cycling and external power meter is incorporated in a bicycle.

17. A system according to claim 15 or 16, wherein the system comprises a sensor arrangement configured to detect at least one parameter relating to the orientation of a foot of the user with respect to gravity, and wherein the system is additionally configured

25 to analyse the joint force in the three planes of the ankle.

18. A system according to claim 17 wherein the system is configured to use the joint force values to calculate the ankle joint moment and I or the ankle joint power and I or the ankle joint work done.

Intellectual

Property

Office

Application No: GB1619784.0 Examiner: Dr David Palmer