WO2008076503A2

WO2008076503A2 - Generation of user activity feedback

Info

Publication number: WO2008076503A2
Application number: PCT/US2007/081711
Authority: WO
Inventors: Katrin Mueller; Andreas Schaller
Original assignee: Motorola, Inc.; Turlik, Iwona
Priority date: 2006-12-13
Filing date: 2007-10-18
Publication date: 2008-06-26
Also published as: WO2008076503A3; US20080146416A1

Abstract

A system for generating a user activity feedback comprises a sensor device (101) and a user device (103). The sensor device (101) comprises a force sensor (105, 107) which determines a measured force distribution resulting from a user activity, such as a sporting or exercise activity. A transmitter (109) transmits the measured force distribution to the user device (103) where a receiver (111) receives the measured force distribution. A context data processor (115) provides context data for the user, such as e.g. environment data or activity equipment data. A target processor (117) determines a target force distribution for the user activity in response to the context data and a feedback processor (113) generates the user activity feedback in response to the measured force distribution and the target force distribution.

Description

GENERATION OF USER ACTIVITY FEEDBACK

Field of the invention

The invention relates to generation of user activity feedback and in particular, but not exclusively, to generation of feedback for exercise and sporting user activities .

Background of the Invention

Recent decades have seen an explosive growth the volume and types of personal activities, such as sports, leisure and entertainment activities performed by people. Furthermore, a significant improvement has been made in manufacturing, computing and communication technologies resulting in an increasing number of electronic devices and equipment for monitoring user responses and supporting or enhancing user activities.

For example, in the area of health monitoring electronic devices capable of monitoring a user's physiognomic response during exercise activities have been introduced. E.g. in the health care sector there is a growing amount of real-time wearable systems for monitoring, visualizing and analyzing physiognomic signals.

Specifically, exercise computers have been developed which are capable of receiving signals from a heart rate sensor in order to monitor and assess the user's performance. As another example, computers have been developed which can receive input from a pedometer sensor in order to calculate various characteristics of the performed exercise, such as the distance covered or an average speed of the user during the exercise.

However, existing systems tend to be limited and provide only a very limited feedback on the user activity. Typically, the feedback information is restricted to relatively simple measures such as a heart rate, speed, or duration of the exercise.

Accordingly, an improved system for providing user activity feedback would be advantageous and in particular a system allowing increased flexibility, additional feedback information and/or improved user activity feedback would be advantageous .

Summary of the Invention

Accordingly, the Invention seeks to preferably mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination.

According to an aspect of the invention, there is provided an arrangement for generating a user activity feedback, the arrangement comprising: a sensor device comprising: a force sensor for determining a measured force distribution resulting from a user activity, and means for transmitting the measured force distribution to a user device; and the user device comprising: means for receiving the measured force distribution, context means for providing context data for the user, target means for determining a target force distribution for the user activity in response to the context data, and feedback means for generating the user activity feedback in response to the measured force distribution and the target force distribution .

The invention may allow an improved user activity feedback to be generated. For example, more accurate user activity feedback or enhanced or additional user activity feedback may be generated. Specifically, the arrangement may generate feedback data which not only reflects how a user performs during the user activity but also how the user preferably should perform in the specific circumstances of the user activity. The arrangement may for example generate feedback data suggesting improvements and corrections to the user. The arrangement may for example provide an automated coaching experience for a user performing a sports activity. Thus, the user activity feedback may be exercise or sporting performance indication data.

The user activity feedback may be any data relating to the user activity which depends on the user's actions during the activity. The measured force distribution may be a temporal and/or spatial force distribution. For example, the force distribution may reflect the temporal and/or spatial force variation exerted by one or more of the user's limbs during the user activity. For example, the force distribution may reflect the pressure exerted by one or both of the users feet during the activity. The measured force distribution may include a directly or indirectly measured distribution of e.g. pressures, torques and/or turns.

According to an optional feature of the invention, the user device is a personal communication device. The user device may specifically be a cellular mobile telephone. Thus, the invention may allow the functionality of a personal communication device, which is typically always carried by a user, to be reused to provide an additional user experience and service to the user. Furthermore, existing communication capabilities of the personal communication device may be used to communicate with the sensor device. In addition, the communication capabilities of the personal communication device can be used to enhance the user experience for example by exchanging user activity feedback data, measured force distribution data, target force distribution data and/or context data with other communication devices. In particular, the personal communication device may be used to provide group based user activity feedback.

According to another aspect of the invention, there is provided a method of generating user activity feedback, the method comprising: a sensor device performing the steps of: determining a measured force distribution resulting from a user activity, and transmitting the measured force distribution to a user device; and a user device performing the steps of: receiving the measured force distribution, providing context data for the user, determining a target force distribution for the user activity in response to the context data, and generating the user activity feedback in response to the measured force distribution and the target force distribution. These and other aspects, features and advantages of the invention will be apparent from and elucidated with reference to the embodiment (s) described hereinafter.

Brief Description of the Drawings

Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which

FIG. 1 illustrates an example of an apparatus for generating a user activity feedback in accordance with some embodiments of the invention; and

FIG. 2 illustrates a method of generating user activity feedback in accordance with some embodiments of the invention .

Detailed Description of Some Embodiments of the Invention

The following description focuses on embodiments of the invention applicable to sports user activity feedback being generated on a personal communication device which specifically is a cellular mobile phone. In particular, the description focuses on an example of a skiing user activity where feedback may be provided on the users skiing performance. However, it will be appreciated that the invention is not limited to this application or scenario but may be applied to many other applications and in many other scenarios. In the described embodiments, a sensor device generates a measured force distribution and sends it to a mobile phone for further processing. Specifically, the pressure exercised by a skier's feet is measured (in ski boots, socks or the like) . The pressure is monitored at multiple points or as an area distribution and the left and right foot pressure distributions are combined to allow correlation parameters between these to be determined.

In the example, pressure sensors are attached to the skis or boots and provides information on the ski run in terms of the pressure exerted by the user on the skis/boots (or vice versa) . The pressure data is compared to a target force distribution which specifically can represent an ideal or preferred distribution for the specific ski run. Thus, the comparison can generate advanced user activity feedback data to the skier including for example a feedback suggesting corrections to be made by the skier during the ski run. For example, a real-time correction feedback may be provided to the user thereby providing an effective real-time automatic coaching experience. As a specific example, during a turn the system can detect that the user is putting too much pressure on one of his feet and may accordingly inform the user to shift his weight from one ski towards the other.

The measured pressure/force profile for the skier is compared to a target pressure profile which depends on the context of the user activity. Specifically, context data is generated for the user activity and used to determine the appropriate target pressure profile. The context data may for example include information of the environment in which the user activity takes place such as a location, height, temperature etc. As another example, at the context data may include information of the equipment that is used by the user. For example, for pressure sensor devices implemented in ski boots the context data can include an indication of whether the ski boots are used for snowboarding or conventional skiing. The target pressure profile may be selected accordingly in order to provide accurate feedback data that reflects the actual performed user activity.

The sensor data is thus used in an intelligent analysis which also considers context data for the user activity to generate a complex and detailed feedback. The realtime feedback may for example be determined based on a number of rules and criteria that are assessed in response to the measured pressure profile and the target profile. In the specific skiing example such rules and criteria can for example include:

• For prepared slopes front pressure should be higher than back pressure.

• Pressure should not exceed a given threshold for a given user weight.

• Higher left pressure indicates left curve. • Pressure changes between left and right indicates curve changes.

• Low pressure and long time until pressure changes indicates long curve/large radius of curve and low speed. • Low pressure and short time until pressure changes indicates long curve/large radius of curve and high speed. • High pressure and short time until pressure changes indicates short curve/small radius of curve and high speed.

Based on an evaluation of such rules for both the measured profile and the target profile, real time feedback can be generated which provides guidance on where to put more pressure (front/back and left/right) , which types of slope are preferable, when to slow down the activity etc.

The feedback can be provided to the user in any suitable form. For example, sound can be modulated (e.g. tempo and pitch) based on the feedback data. E.g. the rhythm frequency of a generated sound signal can be modified to reflect how closely the user's performance matches that of the target profile (corresponding to the preferred/ideal performance) and the pitch can be used to indicate whether the user should shift pressure from one foot to the other (e.g. the sound changes form a nominal pitch depending on how much the pressure distribution deviates from the desired pressure distribution) . A change towards a higher pitch can indicate that the user should shift the pressure towards the left foot and a change towards a lower pitch can indicate that the user should shift pressure towards the right foot.

FIG. 1 illustrates an example of an apparatus for generating a user activity feedback. The apparatus comprises a sensor device 101 which is capable of generating a measured force distribution and transmitting it to a user device which in the specific example is a mobile phone 103. The mobile phone 103 can process the measured force distribution and compare it to a target force distribution which is derived from context data for the user.

The sensor device 103 comprises a number of sensors 105 which in the specific example are pressure sensors located in the soles of a pair of ski boots such that the pressure exerted on the skis by the ski boots can be measured. In the example, each of the boots comprises a plurality of pressure sensors distributed over the sole. Thus, the pressure sensors may measure a force exerted by the user on the skis and in particular measure how this is distributed between the boots and over the area of each boot. Pressure sensors may for example measure the force towards the front of the boot, the left side of the boot, the right side of the boot and towards the back of the boot.

The sensors 105 are coupled to a sensor processor 107 which generates a force distribution which reflects the force distribution exerted the ski boots on the skis.

The measured force distribution can be a spatial distribution which indicates how the forces are distributed over a given area at a specific time. In the specific example, the different pressure sensors can be combined in the measured force distribution which accordingly may provide information of the instantaneous force distribution and accordingly the weight distribution of the user.

Alternatively or additionally, the force distribution may be a temporal distribution. For example, the measured force distribution may comprise information showing how the exerted pressure on one or more pressure sensors varies with time. In this example, the sensor processor 107 can create a measured force distribution by combining the measured pressure values during a given time interval. Thus, the measured force distribution can be both a temporal and a spatial distribution.

The sensor processor 107 is coupled to a transmitter 109 which is arranged to transmit the measured force distribution to the mobile phone 103. The mobile phone 103 furthermore comprises a receiver 111 which is arranged to receive the measured force distribution from the sensor device 101.

In the example, the mobile phone 103 is a cellular telephone such as a GSM or UMTS telephone. However, the communication between the sensor device 101 and the mobile phone 103 does not use the cellular communication system but rather uses a dedicated short range air interface communication link. For example, the mobile phone 103 and the sensor device 101 may use a propriety air interface standard or may communicate using a public short range communication standard such as Bluetooth™.

The receiver 111 is coupled to a feedback processor 113 which is arranged to generate user activity feedback in response to the measured force distribution. Furthermore, the mobile phone 103 comprises a context data processor 115 which is arranged to provide context data for the user. As a simple example, the context data processor 115 may comprise data relating to a plurality of different ski runs or ski slopes. Alternatively or additionally, the context data processor 115 may comprise data relating to a plurality of skis or ski boots. Furthermore, the context data processor 115 may be able to select the specific context data in response to a user input. For example, the user can specifically select the ski slope, the skis and the ski boots for the current user activity.

The context data processor 115 may in some embodiments be arranged to receive all or part of the context data from an external source. For example, context data can be received over a radio air interface (e.g. a cellular air interface supported by the mobile phone 103) .

The context data processor 115 is coupled to a target processor 117 which is arranged to determine a target force distribution for the user activity in response to the context data. For example, the context data processor 115 may provide an indication of which ski slope is currently being skied by the user. In addition, the context data processor 115 may provide an indication of the equipment used e.g. of which skis and which ski boots are used. In response, the target processor 117 generates a target force distribution which may correspond to a distribution for a reference performance for the user activity. For example, the target force distribution can correspond to the force distribution which would be or has been produced by an experienced skier on the specific slope using the specific skis and boots.

In many embodiments, the target processor 117 may comprise a store containing a large number of target distribution profiles. These may for example be generated by recording the measured force distribution generated by experienced skiers using the specified equipment on the specified slope. Furthermore, the measured force distributions for a number of skiers and/or ski runs can be recorded and the average measured force distribution can be stored as the target force distribution for the corresponding context data. Thus, the target processor 117 can comprise a number of target force distributions for different contexts produced during e.g. a design, development and test phase of the user feedback apparatus. The target processor 117 can simply compare the selected context data with corresponding context data stored for each target force distribution and select the target force distribution with matching context data.

The target force distribution is fed to the feedback processor 113 where it is compare to the measured force distribution to generate a feedback indication.

For example, the mobile phone 103 may continuously receive a spatial force distribution representing the pressure exerted by the user on the skis. This may continually be compared to the data of the target profile by the feedback processor 113. Thus, the feedback processor 113 can continually monitor how much the current force distribution deviates from the corresponding force distribution generated by experienced skiers on the specific ski slope. The feedback processor 113 can continuously and in real time generate an indication which reflects the current deviation.

It will be appreciated, that the above example is a simple example provided to illustrate the applied principles. A practical system may typically include complex analysis of the measured force distribution relative to the target force distribution. For example, the feedback processor 113 may be arranged perform pattern matching between the measured force distribution and the target force distribution in order to align data of these. For example, the feedback processor 113 may be arranged to match a pressure pattern of the measured force distribution to a similar pattern in the target profile before the comparison between the two is performed. This may for example correspond to matching the force distribution data of a specific turn of the ski slope to the target distribution data for the same specific turn.

The feedback processor 113 is coupled to a presentation processor 119 which is arranged to present a feedback to the user depending on the user activity feedback generated by the feedback processor 113. In the example, the presentation processor 119 is further coupled to a user interface 121 which may output a suitable signal to the user. The user interface 121 can e.g. include a speaker or a display.

The arrangement of FIG. 1 can thus in the specific example compare stored data for the ski track to the measured pressure distribution resulting from a user skiing the track. It can then present the user with real time feedback depending on the comparison. The real time feedback can e.g. be provided as sound, light effects, vibration or other effects.

For example the feedback processor 113 may generate a feedback signal which indicates whether the user should shift his weight towards the left or right foot. The presentation processor 119 may control the user interface 121 to generate a tone with a pitch that increases the more the user should shift his weight towards the left foot. Thus, a user may simply hear a tone which has a nominal pitch during correct/acceptable skiing. However, if the user should currently shift his weight towards the left foot the pitch of the tone may increase substantially above the nominal pitch. Similarly, if the user should shift his weight towards the right foot the pitch of the tone may be reduced substantially below the nominal pitch. Thus, a simple to understand feedback signal which can assist the user in improving his skiing ability can be provided.

It will be appreciated, that in many embodiments more complex feedback data is generated and provided to the user. For example, the presentation processor 119 can comprise a large number of spoken words which can be selected in response to the feedback data. Also, it will be appreciated that the feedback need not be real-time but can be provided e.g. after the user activity. For example, a user may ski a specific slope and afterwards be provided with a spoken review of the run including specific recommendations for improvements (e.g. "next time, try to shift more weight to the right foot when turning left" or "lean forward when going straight") .

The context data may specifically comprise user activity environment data. This environment data may reflect the environment in which the user activity is performed. For example, data may be provided which reflects the conditions such as the temperature, whether it is raining or snowing, visibility, consistency of the snow etc. The data may be provided manually by the user and/or may be generated from measurements. For example, the mobile phone 103 or the sensor device 101 may comprise a thermometer arranged to measure the ambient temperature. If the thermometer is located within the sensor device 101, the measurement data may be communicated to the mobile phone using the same communication functionality that is used for the measured force distribution.

The context data may alternatively or additionally comprise user activity equipment data. For example, the context data may include an indication of one or more characteristics of the skis used by the user (e.g. carve size, length of ski etc) . This information may for example be entered manually by the user. As another example, the user equipment can have an RFID (Radio Frequency Identification) tag attached which transmits information of the equipment characteristics to an RFID receiver of the mobile phone 103.

The mobile phone 103 may comprise a plurality of context data sets associated with different user activities. For example, a first set of context data comprising snow conditions, temperature, visibility, ski properties etc may be stored for an alpine downhill skiing user activity. In addition, a second set of context data comprising the same or other parameters may be stored for a slalom skiing user activity. Thus, depending on the user activity, different context data sets may be used.

Also, it will be appreciated that the context data processor 115 may comprise a number of different context data profiles which can be selected (e.g. by the user) . Furthermore, the context data profiles may be selected in response to the measured force distribution.

Similarly, the target processor 117 may store a number of different target force distributions. Indeed, in some embodiments the target processor 117 may store different target force distributions for the same context data and the specific target force distribution to be used may be selected in response to the measured force distribution. For example, a pattern match may be performed between the measured force distribution received from the sensor device 101 and the stored target force distributions. The target force distribution most closely resembling the measured force distribution may then be selected and used for the comparison by the feedback processor 113.

In some embodiments, the mobile phone 103 may furthermore comprise functionality for storing a target force distribution determined in response to the measured force distribution. For example, the measured data for a first run may be stored and used as the reference target force distribution during the next run. Accordingly, the user activity feedback system can directly provide information that indicates the user's performance variations and which may specifically include an indication of whether the user is improving or not.

As another example, the mobile phone 103 may be arranged to generate a target force distribution by averaging a plurality of measured force distributions. This will allow the mobile phone 103 to provide instant feedback of how the current performance deviates from an average performance. This may be particularly interesting for user activities where consistency and reproducibility is important (such as e.g. golf swings).

In the specific example, the feedback processor 113 generates feedback data which is indicative of how much a current user performance deviates from a target/reference performance. Thus, the feedback processor 113 can determine a difference measure which is indicative of a difference between the measured force distribution and the selected target force distribution. For example, the feedback processor 113 can simply determine the normalised difference between the sensor measurement values for the current performance compared to the same measurements for the reference performance. However, it will be appreciated that in other embodiments, other and more complex criteria and algorithms may be used by the feedback processor 113.

In some embodiments, the mobile phone 103 comprises functionality for determining a location of the mobile phone 103. Specifically, the mobile phone 103 can comprise a GPS (Global Positioning System) receiver or can use cellular positioning systems to determine a location.

The location information can be used to determine the target force distribution. For example, the target processor 117 can comprise target force distributions for a plurality of different ski slopes with an indication of a location of each ski slope. By comparing a current location of the mobile phone 103 to the locations of the stored ski slopes, the target processor 117 can automatically select the target force distribution for the ski slope where the user is currently located.

In some embodiments, the feedback processor 113 may furthermore determine the user activity feedback in response to the location data. For example, the location data may indicate the user's current position on the ski slope and may accordingly be used by the feedback processor 113 to match the measured force distribution currently being received to the data of the target force distribution. As an example, the target force distribution may link the stored force data to specific locations on the ski slope. The stored data for a right turn may be linked to location data reflection the exact location of that right turn. When the location data of the mobile phone 103 corresponds to the location of the right turn (and assuming the mobile phone is carried by the user) , the data stored for the right turn is extracted and compared to the received measurement data.

In some embodiments the feedback data is furthermore determined in response to user data which is indicative of a characteristic of the user. For example, data indicating whether the user is an experienced skier may be used to generate feedback data. Thus, the feedback system of FIG. 1 may provide different coaching feedback depending on whether the user is a novice skier or an experienced skier.

As another example, the feedback processor 113 may determine the feedback data in response to a weight of the user. In some embodiments, different target force distributions can e.g. be stored for different weights. This user data may for example be entered manually by the user or e.g. determined/calibrated from the pressure measured by the sensor when the user is at rest.

In some embodiments, the user characteristic or user data may include user goals or targets. For example, the user data may include e.g. a desired speed or direction. The target distribution may thus be selected to reflect this user goal .

In the above example, the feedback system was described as a single user system. However, in some embodiments the system is arranged to provide a multi user experience. For example, feedback data relating to the performance of a group of users may be generated. Specifically the performance of the individual user compared to the rest of the group of users can be determined and fed back to the user (s) .

Specifically the mobile phone 103 can receive measured force distributions for a plurality of users. For example, the mobile phone 103 may be capable of receiving data from more than one sensor device. Alternatively or additionally, the mobile phone 103 can comprise a cellular transceiver 123 which is coupled to the feedback processor 113 and the presentation processor 119 and which can receive measured force distribution data from other mobile phones 103 via a cellular communication link. Thus, a second mobile phone (not shown) can receive measured force distribution data from a sensor device and transmit this to the cellular transceiver 123 from where it is forwarded to the feedback processor 113. Similarly, the mobile phone 103 may also be able to transmit the measured force distribution data received from the sensor device 101 to other mobile phones.

In the example, the feedback processor 113 can generate a user activity feedback which does not only depend on the measured force distribution received from the sensor device 101 but also on the measured force distribution received from the second mobile phone. For example, the feedback processor 113 may generate a difference distribution between the two measured force distributions and compare this to a target difference distribution in order to generate the feedback signal. Thus, the feedback signal may reflect not only one user' s performance during the user activity but also how this performance is relative to the performance of another user. Such a feature may for example be of significant importance in user activities such as synchronised skiing.

As another example, the mobile phone 103 may receive user activity feedback from another mobile phone. For example, feedback data may be generated by another mobile phone by comparing a received measured force distribution and target force distribution similarly to what has been described for the first mobile phone 103. This second user activity feedback data is then transmitted to the cellular transceiver 123 using the communication functionality of the cellular communication system. The feedback data is fed to the presentation processor 119 which also receives the feedback data from the feedback processor 113. The two sets of presentation data are then combined to generate a single combined user activity indication. For example, a single audio signal indicating how well the user is performing relative to the other user may be generated.

It will be appreciated that in more complex embodiments, more complex combinations and user activity indications may be provided. For example of the relative performance of one user compared to another user may be plotted onto a map of the ski slope thereby clearly indicating at which parts of the course each user achieves the best performance.

It will be appreciated that the group data exchange may use the cellular communication system as described above but may alternatively or additionally use other communication means including for example WiFi™ or Bluetooth™ short range communication means.

It will be appreciated that the generation of the feedback data may be further in response to many other parameters than the measured force distribution. For example, the feedback signal may be generated in response to a combination of the measured force distribution and additional measurements, such as for example a heart rate or blood pressure measurement.

Thus, the system of FIG. 1 may provide an enhanced user experience and may in particular provide improved, additional and/or enhanced assessment and feedback on the user activity.

FIG. 2 illustrates a method of generating user activity feedback in accordance with some embodiments of the invention . The method initiates in step 201 wherein a measured force distribution resulting from a user activity is generated by a sensor device.

Step 201 is followed by step 203 wherein the sensor device transmits the measured force distribution to a user device.

Step 203 is followed by step 205 wherein the user device receives the measured force distribution.

Step 205 is followed by step 207 wherein the user device provides context data for the user.

Step 207 is followed by step 209 wherein the user device determines a target force distribution for the user activity in response to the context data.

Step 209 is followed by step 211 wherein the user device generates the user activity feedback in response to the measured force distribution and the target force distribution .

It will be appreciated that the above description for clarity has described embodiments of the invention with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units or processors may be used without detracting from the invention. For example, functionality illustrated to be performed by separate processors or controllers may be performed by the same processor or controllers. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

The invention can be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a single unit or may be physically and functionally distributed between different units and processors .

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term comprising does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate. Furthermore, the order of features in the claims does not imply any specific order in which the features must be worked and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order.

Claims

1. An arrangement for generating a user activity feedback, the arrangement comprising: a sensor device comprising: a force sensor for determining a measured force distribution resulting from a user activity, and means for transmitting the measured force distribution to a user device; and the user device comprising: means for receiving the measured force distribution, context means for providing context data for the user, target means for determining a target force distribution for the user activity in response to the context data, and feedback means for generating the user activity feedback in response to the measured force distribution and the target force distribution.

2. The arrangement of claim 1 wherein the context data comprises user activity environment data.

3. The arrangement of claim 1 wherein the context data comprises user activity equipment data.

4. The arrangement of claim 1 wherein the context means is arranged to determine the context data as a context data set selected from a plurality of context data sets associated with different user activities.

5. The arrangement of claim 1 wherein the target means is arranged to select the target force distribution in response to a characteristic of the measured force distribution .

6. The arrangement of claim 1 wherein the user device further comprises means for storing a target force distribution determined in response to the measured force distribution .

7. The arrangement of claim 1 wherein the user device further comprises means for storing a plurality of target force distributions linked to context data characteristics and the target means is arranged to retrieve a target force distribution linked to a context data characteristic matching the context data.

8. The arrangement of claim 1 wherein the feedback means comprises means for determining a difference measure indicative of a difference between the measured force distribution and the target force distribution and to determine the user activity feedback in response to the difference measure.

9. The arrangement of claim 1 wherein the user device furthermore comprises location means for determining location data for the user device.

10. The arrangement of claim 9 wherein the target means is arranged to determine the target force distribution in response to the location data.

11. The arrangement of claim 9 wherein the feedback means is arranged to determine the user activity feedback in response to the location data.

12. The arrangement of claim 1 further comprising means for providing user data indicative of a characteristic of the user; and wherein the feedback means is arranged to determine the user activity feedback in response to the user data.

13. The arrangement of claim 1 wherein the measured force distribution comprises at least one of a temporal force distribution and a spatial force distribution.

14. The arrangement of claim 1 wherein the user device comprises means for receiving measured force distributions for a plurality of users; and the feedback means is arranged to determine the user activity feedback in response to the measured force distributions.

15. The arrangement of claim 1 wherein the user device further comprises presenting means for presenting the user activity feedback to a user.

16. The arrangement of claim 15 wherein the user device further comprises means for receiving a second user activity feedback from another user device; and the presenting means is arranged to generate a combined user activity indication in response to the user activity feedback and the second user activity feedback.

17. The arrangement of claim 1 wherein the user device is a personal communication device.

18. The arrangement of claim 1 wherein the user activity feedback is a real time feedback.

19. A method of generating user activity feedback, the method comprising: a sensor device performing the steps of: determining a measured force distribution resulting from a user activity, and transmitting the measured force distribution to a user device; and a user device performing the steps of: receiving the measured force distribution, providing context data for the user, determining a target force distribution for the user activity in response to the context data, and generating the user activity feedback in response to the measured force distribution and the target force distribution .