WO2009013490A1

WO2009013490A1 - Biofeedback orthosis

Info

Publication number: WO2009013490A1
Application number: PCT/GB2008/002519
Authority: WO
Inventors: Mojtaba Kamyab; Brendan Francis Mchugh; Robert James Bowers
Original assignee: University Of Strathclyde
Priority date: 2007-07-24
Filing date: 2008-07-21
Publication date: 2009-01-29
Also published as: GB0714431D0

Abstract

An abdominal exercise control device (10) for reminding a user to perform an exercise at selected intervals. The device (10) comprises a controller (15) for determining when user performance of an exercise is to be initiated and notifying the user to perform the exercise, and a monitoring device (20) for monitoring performance of the exercise by determining the degree of contraction of at least one abdominal muscle.

Description

Biofeedback Orthosis

The present invention relates to a device for promoting performance of an exercise regime, particularly an exercise regime to prevent or alleviate lower back pain.

Background of the invention

Low Back Pain (LBP) is a common physical disorder in working age adults. Studies indicate that 70-80% of the population experience at least one episode of back pain during their lifetime. Interruption to the core stability of the torso has been identified as a major cause of low back pain. A conventional approach to deal with this is to provide a lumbosacral corset. This increases abdominal support by increasing the intra-abdominal pressure. However, this is a temporary solution, not a cure, and can in some cases cause further problems. This is because the corset provides support in place of the local abdominal muscles, which lessens their workload and leads to weakening of these muscles. Weakened local abdominal muscles increase the risk of more serious back problems.

An alternative solution to easing lower back pain problems is increasing the endurance of the deep abdominal muscles by regularly performing an exercise known as the "hollowing manoeuvre". The hollowing manoeuvre involves drawing the abdominal wall in towards the spine in such a way as to not affect breathing, as described by Stevens et. al. in "The influence of specific training on trunk muscle recruitment patterns in healthy subjects during stabilization exercises", Manual Therapy and by O'Sullivan et al in "Evaluation of Specific Stabilizing Exercise in the Treatment of Chronic Low Back Pain with Radiologic diagnosis of Spondylolysis or Spondylolisthesis", Spine Vol. 22, pages 2959-2967, the contents of which are incorporated herein by reference. The manoeuvre is designed to produce isolated contraction of the transversus abdominis muscle. Function of the transversus abdominis has been shown to have a significant effect on low back pain.

To achieve the best results, the hollowing manoeuvre should be repeated at regular intervals throughout the day. Optimally, each exercise should consist of 10 sets of 10 sub-maximal contractions, each lasting 10 seconds. This is known as the 10x10x10 rule. The improvement achieved using the hollowing manoeuvre is related to the position in which the exercise is performed. Therefore, performance of the exercise whilst the user is in their normal range of day-to-day body positions is preferred. Many patients find performing this exercise according to the prescribed timetable and manner difficult. In addition, selectively using local abdominal muscles is challenging for many patients. Patients are provided with feedback in the form of verbal advice from a healthcare professional or by using a biofeedback device such as a pressure biofeedback device as described in US 5,338,276 or an ultrasound real-time biofeedback device as described by Hides et al in "Use of real-time ultrasound imaging for feedback in rehabilitation" Manual Therapy vol. 3, pages 125-131. However, use of these feedback techniques requires expertise and/or equipment that is generally only found in the clinical environment and is unsuitable for home use. In addition, whilst a range of body positions can be prescribed in which to carry out the exercise in a clinical environment, these can only simulate everyday positions and are often not truly representative of actual body positions adopted in day-to-day life.

Summary of Invention

According to one aspect of the present invention, there is provided an abdominal exercise control device for reminding a user to perform an exercise at selected predefined intervals, the device comprising a controller for determining when user performance of an exercise is to be initiated and generate a signal to notify the user to perform the exercise, and a monitoring device for monitoring performance of the exercise by determining the degree of contraction of at least one abdominal muscle.

By using a simple device to remind a user to perform the exercise under controlled circumstances at selected intervals, an effective way is provided for enforcing and monitoring the execution of an exercise regime that otherwise could only be carried out in a controlled clinical environment under medical supervision.

The exercise may be an exercise of the abdominal muscles. The exercise may be an exercise of the deep abdominal muscles. The muscles may be the transversus abdominis. The exercise may be the "hollowing manoeuvre". The exercise may be the "abdominal drawing-in exercise".

The control unit may be adapted to cause a start signal to be generated for notifying the user to start the exercise and a stop signal for notifying the user to stop the exercise. The stop signal may be generated on successful completion of the exercise or on expiry of a pre-determined time period. The control unit may be adapted to provide a signal when the exercise is being performed according to at least one predefined criteria and/or to provide a signal when the exercise is not being performed according to at least one predefined criteria and/or the exercise has been successfully completed to at least one predetermined criteria. The criterion may be the duration of the exercise and/or the range of motion in at least a part of the exercise.

The device may include a timer that is adapted to time and schedule actions relating to the exercises. For example, the timer may be operable to time a period when the device is inactive and signal when an active period should begin. Additionally or alternatively, the timer may be configured to time the duration of performance or non- performance of an exercise. This may be done according to pre-defined conditions. The timer may be operable to generate a signal indicative of an active period or fault period threshold.

The monitoring device may be adapted to measure the circumference of a user's waist. The monitoring device may comprise a belt. The belt may comprise at least one non-elastic section and/or at least one elastic section. The monitoring device may include means for monitoring changes in the length of the belt. The means for monitoring may include at least one of a potentiometer, an optical sensor, a tension meter and a strain gauge. The means for monitoring may be adapted to monitor changes in the length in the elastic section of the belt.

The exercise control device may further comprise at least one feedback device for conveying signals from the control unit to the user. The feedback device may be a vibratory device and/or a display and/or an audio device.

The control unit may further comprise a memory for storing the results of each exercise. Data logged may include the time the belt has been worn, the number of faults recorded, the number of cancellations and/or the number of successful exercise regimes performed.

The control unit may be provided with means for communicating with or connecting to a processor, for example an external processor, such as a personal computer, so that data stored therein can be transferred for remote analysis. The control unit may be adapted to allow configuration of operating parameters. Configurable operating parameters may include the rest period between exercise regimes and/or the active exercise period. Additionally or alternatively, the configurable operating parameter may be the fault time. This is the time allowed for a user to respond to the trigger to exercise. In the event that the user does not respond within this time, a fault is recorded.

Brief Description of the Drawings

Various aspects of the invention will now be described by way of example only with reference to the accompanying drawings, of which:

Figure 1 is a schematic showing a cross-section through the waist area of the torso, demonstrating the action of the muscles in carrying out a hollowing manoeuvre;

Figure 2 shows an exercise control device; Figure 3 shows an alternate exercise control device in use by a user;

Figure 4a is an internal schematic of a control unit for the exercise control device of Figure 2 or Figure 3;

Figure 4b is an external view of the control unit of Figure 4a; Figure 5 is a view of part of an exercise monitoring device for use with the exercise control device of Figure 3;

Figure 6 is a view of the exercise monitoring device of Figure 5 in use by a user;

Figure 7 is a schematic of the exercise monitoring device of Figures 5 and 6 in use by a user; and Figure 8 shows a flowchart indicating the operation of the exercise monitoring device of Figure 2 or Figure 3.

Detailed Description of the Drawings As shown in Figure 1 , the transversus abdominis 5 is the deepest abdominal muscle and wraps around the waist area. The transversus abdominis 5 and various non- contractable structures such as the thoracolumbar fascia and the abdominal fascia form an internal corset in the waist area. This internal corset is a major factor for enhancing lumbar and core stability. The transversus abdominis 5 consists of horizontal muscle fibres, which run laterally around the waist portion of the torso. Thus, the concentric contraction of the transversus abdominis 5 results in a decrease of the waist circumference. This change in waist circumference can be used as a way of monitoring the contraction of the transversus abdominis 5.

Figure 2 shows an exercise control device 10 for initiating and guiding a user through performance of a regime of "hollowing manoeuvres" to treat or prevent lower back pain and for recording the user's performance. The hollowing manoeuvre involves drawing the abdominal wall in towards the spine using the deep abdominal muscles and particularly the transversus abdominis 5 in such a way as to not affect breathing.

The exercise control device 10 has a control unit 15 mounted on and connected to an exercise monitoring device 20. In an alternative embodiment, the control unit 15 is mounted separately, as shown in Figure 3.

The exercise monitoring device 20 monitors changes in the circumference of the waist and provides signals indicative of waist circumference to the control unit 15. The control unit 15 is adapted to notify a user wearing the exercise control device 10 of a time to begin exercising, thereby initiating performance of the exercise. It also receives signals indicative of waist circumference from the monitoring device 20 and uses such signals in conjunction with pre-defined exercise conditions to monitor and record performance of certain actions relating to the exercise against pre-defined criteria. The control unit 15 is arranged to signal the user if the exercise is not being performed to the pre-defined criteria.

Figure 4a shows the internal components of the control unit 15. This includes a central processor 25 connected to a memory 30, a timer 40, a PC communications port 45 to allow a user to access and download data from the memory 30, and a measurement device communications port 50 for allowing the processor 25 to communicate with the measurement device 20 in order to receive signals indicative of the circumference of the waist. The measurement device communications port 50 is adapted to communicate with the measurement device 20 by wired or wireless connection, such as Bluetooth, infrared or radio frequency connection. As shown in Figure 4b, the control unit 10 also has a display 55 for communicating information to the user, a cancel button 60 for aborting a prescribed exercise, an ok button 65 and calibration buttons 67 for providing input to the control unit 10. The button 65 may be used to determine if the data to be input is for a new day or the continuation of an existing day or to confirm that calibration data is to be accepted. The processor 25 controls the device 15 and in particular controls when an exercise has to be performed. To notify the user of when the exercise routine has to start, a vibratory device 35 is provided. This is operable to receive a start signal from the processor 25 at the pre-determined time or interval of time and vibrate when the exercise is to be started. This vibration can be felt by the user and is the trigger to let him know that it is time to start the exercise session or routine. The vibratory device 35 can be provided as part of the control unit or separately therefrom, as shown in Figure 5. In either case the vibratory device 35 has to be able to receive signals from the control unit over a wired or wireless connection and produce a vibration of a sufficient level to be detectable by a user.

In order to time and schedule the actions relating to the exercises, the processor 25 co-operates with the timer 40. This involves timing a period when the exercise control device 10 is inactive and signalling the processor 25 when an active period should begin. Further functions of the timer 40 include timing the length of time that an exercise is, or is not, being performed according to the pre-defined conditions and signalling the processor 25 when that time reaches an active period threshold or fault period threshold respectively.

The memory 30 is arranged to store counters, including a success counter for logging each completion of a hollowing manoeuvre where the transversus abdominis 5 is contracted by at least a predefined amount for a predefined period of time; a fault counter for logging each time a user fails to contract the transversus abdominis 5 for the predefined period of time during an active period; and a cancellation counter for logging each time the user cancels a request by the exercise control device to perform a hollowing manoeuvre. The memory 30 also acts in conjunction with the timer 40 to record the time for which the belt has been worn.

Figure 6 shows the exercise monitoring device 20 in more detail. This has a belt 70 having an elastic portion 75 and a non-elastic portion 80. The non-elastic portion is resistant to creep, i.e. it has no permanent change in its length as the result of long term tension. The non-elastic portion is retractable and maintains substantially constant length throughout the exercise. The belt 70 is provided with fixings 85 for attaching it around a user's waist, as shown in Figure 7, and adjusting means 90 to adjust the belt 70 to fit the user. Preferably, the device 20 is mounted next to the user's skin to allow optimal feedback to the user. An indicator of a potentiometer 100 runs through the elastic portion 75 of the belt 70 and connects to the non-elastic portion 80 of the belt 70. Any change in waist circumference changes the length of the elastic portion 75 of the belt 70 and results in movement of the potentiometer indicator 100. This movement is detected by the potentiometer indicator 100, which generates a signal that is indicative of the motion and thereby the circumference of the waist. The potentiometer has an output port that is operable to transmit the signal to the control unit 15 via the measurement device communications port 50.

Before the device is used, it must be set up with operational parameters. Input of the parameters may be via use of buttons on the device 10 in response to prompts displayed on the screen 55. Operational parameters include the manoeuvre duration, a rest period time and a fault record period time. The manoeuvre duration defines the time in which the user should be performing the exercise. The rest period defines the time between performances of each exercise. The fault record period is the length of time that non-compliance with the exercise regime will be allowed before the machine records the exercise as being not completed. The fault record period is the maximum time during an active period in which the device determines that no satisfactory contraction is being carried out before the device signals a non- compliance fault. Typically, the rest period ranges between 2 to 32 minutes, with a default of 2 minutes. The manoeuvre duration may range between 5 to 80 seconds, with a default of 10 seconds. The fault period is settable between 2 and 12 seconds with a default of 2 seconds.

As part of the initialization, the optimum belt 70 length associated with successful performance of the hollowing manoeuvre (the hollowing manoeuvre initiation length) is determined. The processor 25 monitors the circumference of the waist and any contraction that decreases the waist circumference below the hollowing manoeuvre initiation length for the specified duration of the manoeuvre is deemed to be an indication that the required contraction has been successfully performed. The hollowing manoeuvre initiation length is defined using the following relation:

hollowing manoeuvre initiation length = 0.3(relax length - contract length) + contract length

The relax length is the length of the belt 70 when the abdominal muscles are relaxed and the contract length is the length of the belt 70 when the abdominal muscles are maximally contracted. The calibration is carried out by the wearer relaxing the transversus abdominis and pressing one of the buttons 67, and then performing the hollowing manoeuvre and pressing the button 67 again. Instructions are displayed on screen 55 each time. Then the control unit 15 calculates the waist circumference equivalent to satisfactory completion of the hollowing manoeuvre using the above relation and use this thereafter as the threshold value.

Figure 8 shows the steps taken in the use of the device. Initially, the device 10 is in a rest state. The timer 40 is operable to determine the time elapsed since the device entered the rest state and to signal the processor 25 when the rest period set during initialisation has been completed. The processor 25 then activates the vibratory feedback device 35 to provide a long vibration to the user to indicate the start of an active period. During the active period, the user should perform a hollowing manoeuvre. Throughout the active period, the processor 25 monitors the waist circumference as determined by the meter 100 on the measurement belt 70. If the processor 25 determines the waist circumference to be less than the hollowing manoeuvre initiation length then the vibration device 35 is kept in the inactive state.

The timer 40 is operable to measure the time that the waist circumference is less than the hollowing manoeuvre initiation length. Should the waist circumference of the user remain below the hollowing manoeuvre initiation length for the manoeuvre duration time, the timer 40 signals the processor 25 that the active period is complete and the controller increments the success counter. The processor 25 activates the vibratory device 35 to provide a long vibration to the user to indicate the end of an active period. The user will typically be asked to perform 100 successful manoeuvres per day to conform to the 10x10x10 rule. However the control unit 15 can be adjusted for any number of manoeuvres based on any specific requirement. If the success counter shows that 100 successful manoeuvres have been completed, then the implementation of the active periods ends. The end of 100 successful active periods is indicated by a message on the screen 55 and a long buzz. If the success counter shows fewer than 100 successful manoeuvres completed, then the processor 25 continues to activate the vibrator device 35 to provide long vibrations to initiate more active periods until 100 successful active periods/hollowing manoeuvres have been achieved.

If the waist circumference exceeds the hollowing manoeuvre initiation length during the active period, then the processor 25 activates the vibratory motor 35 to inform the user that they need to contract the transversus abdominis 5 further by a series of short vibrations. The timer 40 is operable to monitor the time that the waist circumference is above its required value. If this time exceeds the fault record period that was specified during initialisation then the processor 45 deactivates the vibratory device 35 and signals an audible tone to indicate unsatisfactory performance of the required manoeuvre. The processor 45 then increments the fault counter and returns the exercise control device 10 to a rest state.

If the user does not wish to carry out the recommended manoeuvre during the active period, the user may cancel the active period using the cancellation button 60.

Operation of the button 60 prompts the processor 25 to deactivate the vibration motor

35, increment a cancellation counter and end the active period before returning the control device 10 to the rest state. Thus, the control device 10 remains in the active state until either a hollowing manoeuvre is performed by the contracting the transversus abdominis by the required amount and for the required duration, or the user fails to contract the transversus abdominis for the required amount and for the fault record period, or the user operates the cancel button 60. When the device 10 is returned to the rest state, the timer 40 is reset and the process begins again and is repeated until the success counter reaches 100 successful manoeuvres, whereupon the process ends.

As described above the main application of the invention is for the treatment of lower back pain. However, it could equally be used for the purposes of controlling a more general abdominal exercise routine. The transversus abdominis attaches to the thoracolumber fascia in the posterior of the torso and the abdominal fascia in the anterior of the torso. These three elements construct a musculofascial corset around the waist. The transversus abdominis is the only contractible component of the musculofascial corset. Since the transversus abdominis is a tonic muscle, improvement of its muscle capacity will result in a decrease in its rest length with a corresponding decrease in waist circumference. Therefore, the device and method of the invention may also be utilised as a general exercise device for cosmetically improving the condition and size of the waist region.

A skilled person will appreciate that variations of the disclosed arrangements are possible without departing from the scope of the invention. For example, whilst the waist circumference is described as being measured using a belt, other suitable devices may be used. Whilst the change in length of the elastic component of the belt is described as being measured using a potentiometer, other devices capable of sensing changes in length may be used. Additionally, whilst the waist contractions are described as being caused predominantly by use of the transversus abdominis, other muscles may be involved or the apparatus may be adapted to be used with other muscle groups. Furthermore, although a vibratory device 35 is used to notify the user of the time to start the exercise, other means of communication may be used such as audio signals, visual signals or displays.

Claims

1. An abdominal exercise control device for reminding a user to perform an exercise at selected intervals, the device comprising a controller for determining when user performance of an exercise is to be initiated and notifying the user to perform the exercise, and a monitoring device for monitoring performance of the exercise by determining the degree of contraction of at least one abdominal muscle.

2. An abdominal exercise control device as claimed in claim 1 , wherein the exercise is an exercise of the deep abdominal muscles.

3. An abdominal exercise control device as claimed in claim 1 or 2, wherein the muscle is the transversus abdominis.

4. An abdominal exercise control device as claimed in any of claims 1 to 3, wherein the exercise is the "hollowing manoeuvre".

5. An abdominal exercise control device as claimed in any of the preceding claims, wherein the controller is adapted to provide a signal when the exercise is being performed according to at least one predefined criteria.

6. An abdominal exercise control device as claimed in any of the preceding claims, wherein the controller is adapted to provide a signal when the exercise is not being performed according to at least one predefined criteria.

7. An abdominal exercise control device as claimed in any of the preceding claims, wherein the controller is adapted to provide a signal when the exercise has been successfully completed to at least one predetermined criteria.

8. An abdominal exercise control device as claimed in any of claim 5 to 7, wherein the criteria include the time at least a part of the exercise is held or performed for and/or the range of motion in at least a part of the exercise.

9. An abdominal exercise control device as claimed in any of the preceding claims, wherein the monitoring device is adapted to measure the circumference of a user's waist.

10. An abdominal exercise control device as claimed in any of preceding claims, wherein the monitoring device comprises a belt.

11. An abdominal exercise control device claimed in claim 10, wherein the belt comprises at least one non-elastic section and/or at least one elastic section.

12. An abdominal exercise control device as claimed in any of preceding claims, wherein the monitoring device includes means for monitoring changes in the length of the belt.

13. An abdominal exercise control device as claimed in any of preceding claims, further comprising at least one feedback device for conveying signals from the control unit to the user.

14. An abdominal exercise control device as claimed in claim 13, wherein the feedback device is a vibratory device, and/or a display and/or an audio device.

15. An abdominal exercise control device as claimed in any of preceding claims, wherein the control unit further comprises a memory for logging the results of each exercise.

16. An abdominal exercise control device as claimed in claim 15, wherein data logged includes the time the belt has been worn and switched on, the number of faults recorded, the number of cancellations and/or the number of successful exercise regimes performed.

17. An abdominal exercise control device as claimed in any of preceding claims, wherein the control unit is adapted to allow configuration of operating parameters.

8. An abdominal exercise control device according to any claim 17, wherein the configurable operating parameters include a rest period between exercise regimes, an active period and/or a fault threshold.