DEVICE AND METHOD FOR ASSESSING CORRECT POSTURAL ALIGNMENT OF AN INDIVIDUAL

Abstract: Many individuals have postural misalignments which can be corrected by the use of alignment accessories, such as wedges for positioning beneath the feet. Correction of postural alignment in this way can improve sporting performance. The invention provides a device and a method for selecting between differently-shaped alignment accessories to optimise postural alignment. The device comprises a sensor (12) having a plunger (22) which can be pressed by an individual. A data acquisition unit (10) records the force applied by the individual and the time taken to apply that force. For each of a number of different alignment accessories the individual is instructed to press the plunger with the greatest force possible (F) for the shortest time possible (t). The data acquisition unit generates an output parameter preferably based on F<2>/t or F/t. The optimum alignment accessory corresponds to the highest output parameter.

Description: DEVICE AND METHOD FOR ASSESSING CORRECT POSTURAL ALIGNMENT OF AN INDIVIDUAL The present invention relates to a device and a method for assessing correct alignment of an individual, particularly as regards the correct support and positioning of his body when the latter uses accessories such as sports accessories. Background of the Invention The human body is known to have imperfections which result in the general morphology being affected by a misalignment of the body. Indeed, firstly the longitudinal axis of the body is usually not completely vertical and secondly the transversal axis at the level of the pelvis is not completely horizontal and thus not perpendicular to the vertical axis and possibly out-of-line. Such misalignments, even if they are insignificant, are entirely detrimental to the carrying out of certain types of sport, particularly the forms of sports requiring correct balance such as skiing, roller skating, cycling or those requiring adapted positioning and comfort, such as amateur pilot training. To date, by means of shaped wedges with selected dimensions, it is possible to correct front and rear lateral imbalances so as to allow the skeleton to work in the best possible conditions. In practice, through empirical assessments, it is possible to determine from the reactions of the user whether the wedges enable him to find a better positioning and so provide him with better sensations when he is equipped with such accessories. Kinesiology is a form of science dealing with muscular tone (tonicity) and a feeling of well-being. It has thus been proved that there is a direct relation between muscular tone and good alignment and thus a correct balance of the skeleton. The moment the skeleton is correctly aligned, the user can put his own capacities to good use. Nevertheless, the conventional assessment described above is empirical and remains a matter for specialists. The practitioner needs to have special training so as to determine the muscular feeling of the individual being tested and to be able to assess the tone differences resulting from the selected wedges by determining which of these provide the user with the best possible muscular sensations. This is a delicate matter since, depending on the type of imbalance, the wedges generally differ on one side to the other and this disturbs judgement and complicates the number of tests. Summary of the Invention The invention provides a device and a method for determining correct alignment of an individual's posture as defined in the appended independent claims. Preferred or advantageous features of the invention are set out in dependent subclaims. Thus, in a preferred embodiment the present invention may offer a device making it possible comparatively, controllably and repeatably to measure the muscular tone of any individual so as to determine the best suitable wedges or other alignment accessories during an alignment operation. If one takes as an example the hiring of skis, it can be understood that it is desirable to be able quickly and reproducibly to determine correct alignment. Moreover, this operation should be relatively simple for the person concerned. These objects may advantageously be enabled using the device and method of the invention. The device of the invention may advantageously make it possible to dispense with the personal interpretation of the individual being tested, or the interpretation of a skilled practitioner, by using a relatively inexpensive item of equipment which is easy to use and occupies a small space. To this end, in a preferred embodiment the invention provides a device for controlling or determining the correct alignment of an individual's posture, in particular when equipped with a sports accessory, which comprises: - a data acquisition unit - a sensor for measuring the force exerted by an individual and the speed or time of application of this force, and - a link between the sensor and the unit. The sensor may advantageously be an actuator for measuring the force exerted with the thumb of the individual. The force and action speed may be measured when the individual reacts to a signal. In further embodiments, the sensor may be a static sensor held in the hand for measuring the force exerted and the action speed of the thumb on the sensor when the individual is instructed to repeatedly exert a force on the sensor. To test an individual, a device embodying the invention may advantageously be used in any of a number of ways, including the following preferred embodiments. The individual may be instructed to apply as high a force to the sensor as possible in as short a time as possible (or as fast as possible). The data acquisition unit then records the maximum force applied and the time taken to apply it. The time measurement may begin at a small threshold force level rather than at zero force, to reduce errors. The individual may be told to repeat this operation a predetermined number of times, such as 5, 10 or 15 times. Alternatively, each time the individual applies a force to the sensor, the time between two predetermined force values (a low value and a high value) may be recorded. Where repeated tests are performed, the individual may be instructed to repeatedly exert a force which seems to them to be constant on each repetition. In a further variation, the individual may apply a force to the sensor each time a signal, such as a flashing light or an audible sound, is given. The test then incorporates reaction speed. The signal may be controlled by the data acquisition unit so that time from the signal to the maximum application of force could, for example, be recorded. In a further alternative, the sensor can be actively controlled by the data acquisition unit to apply a force to the individual's thumb or hand (for a hand-held sensor). In such an embodiment the sensor could incorporate an electromagnetic or pneumatic drive means or an inflatable bladder. The individual would then be instructed to oppose the force applied by the sensor as quickly as possible when the sensor is actuated. The data acquisition unit would again record the maximum force applied and the time taken to apply that force, or the time taken to reach a maximum threshold force. As in previous embodiments, repeated tests may be performed. In each of these embodiments, for each test the data acquisition unit advantageously evaluates an output parameter based on the force applied and the time taken to apply it. Preferably the parameter is a measure of force (F) divided by time (t) or, particularly preferably, F 2 /t. The parameter may be evaluated in any of a number of ways. For example, the parameter may be based on the recorded maximum force and a recorded total elapsed time, or on the time elapsed between the application of a minimum threshold force and the maximum force, or between predetermined low and high threshold forces. In an embodiment in which the individual responds to a stimulus such as a flashing light, the elapsed time may be measured from when the stimulus is given. Alternatively, the data acquisition unit may continuously log the application of force during a test and evaluate the output parameter as the slope, or a best-fit slope, of a plot of force against time, or force squared (F 2 ) against time. In each case, an output parameter is generated from each test. When the individual performs repeated tests, an average of the output parameters can be calculated by the data acquisition unit, optionally discarding an extreme value or values of the output parameter, such as the maximum and minimum values from a series of tests. In general it is preferred to measure elapsed time from a specific trigger event, to reduce false alarms and erroneous measurements. The trigger may be the applied force rising through a predetermined threshold force or, in tests where the individual responds to a stimulus such as a flashing light or actuation of an active sensor, the time that the stimulus is triggered. Depending on its design, the sensor may be considered to measure applied force or applied pressure. This does not affect the validity or handling of test results which are preferably not intended for comparison of one individual with another, but to assess the muscle tone of one individual when using different posture-enhancing accessories. The invention may also advantageously provide a method for controlling or determining the correct alignment for the posture of an individual, consisting of the following steps: - calibration by testing the individual with no alignment accessory in place, the test comprising the individual exerting a force at least once on a sensor; - installing a first alignment accessory, - testing the individual with the alignment accessory in place and acquiring data from the test; - installing a second alignment accessory instead of the first one, • testing the individual with the second alignment accessory in place and acquiring data; and - installing a nth alignment accessory instead of the n-1 st alignment accessory, • testing the individual with the nth alignment accessory in place, and acquiring data; and • repeating tests with different alignment accessories as required or as convenient and comparing the acquired data so as to determine the optimum alignment accessory. Calibration preferably consists of carrying out at least one measurement, the individual preferably being barefoot on a flat surface so as to measure a value corresponding to a good muscle tone, and at least one measurement with the individual having one foot on an obstacle so as to measure a value corresponding to a poor muscle tone. For each test with each alignment accessory, the individual is preferably made to undergo 10 tests, the two upper extreme and the two lower extreme tests being removed with an average being made of the remaining six. As described above, the invention may find application in the testing of any posture-adjusting accessory, as the skilled person would readily appreciate. Other portions of this document refer to the use of wedges; this is only one example of the application of the invention. The foregoing text describes hand-held sensors but the invention envisages other types. These could be positioned for operation by various parts of the body, such as shoulders, arms or forearms, legs, etc., to test various muscles as appropriate in various sports, (golf, tennis, etc.) or safety requirements. Description of Specific Embodiments and Best Mode of the Invention Specific embodiments of the invention will now be described by way of example, with reference to the accompanying drawings which represent a particular non- restrictive embodiment and are as follows: • figure 1 is a perspective view of a device embodying the present invention, • figure 2 is a symbolised view of the axes of a naturally non-aligned skeleton, • figure 3 is a symbolised view of the same skeleton after correction leading to an alignment, and • figure 4 is a synoptic diagram of the stages for acquiring and processing the stored information. In a first embodiment, the device of the present invention includes an acquisition unit 10, a sensor 12 and an electrical wire or optical link 14 for linking this sensor to the unit. This physical link can be replaced by a wireless link if this is required for good ergonomics, links of this type being commercially available. The acquisition unit includes a microprocessor 16 for running software to collect information measured using the sensor, to store it and to display it on an integrated screen 18. This unit may also include an adapted outlet for diverting the information into a central unit of an office computer comprising further processing software. The software may not only present the results of tests but also associate the wedges used for each test result by a graphic display. Moreover, the results can also be processed for presentation in the form of graphic diagrams, such as plotted curves. The sensor 12 comprises a box or housing 20 adapted to be held in the hand. A plunger 22 extends from the housing for applying the thumb. The dimensions- are preferably chosen so as to be held by either an adult or a child. In this embodiment, the sensor includes a sprung piston type activation button (plunger) 22. Thus, the plunger is slidable within the box and integrated cells enable measurement of the force exerted by the thumb and the time taken to exert said force. These values of force and time reflect the condition of the muscular tone of the individual and vary proportionally for each individual in response to changes in the condition of their muscular tone. Figure 2 shows diagrammatically a skeleton with its mechanical elements, showing a different left foot 24 and right foot 26. The individual is equipped with sport accessories, in this case rigid shoes 28, such as ski boots. The longitudinal axis Y of this individual's skeleton is naturally slanted, which results in certain misalignments at the level of the pelvis and of the transverse axis X corresponding to it. This axis X is not horizontal and, to compensate for it, hip distortions in the individual can be observed. In this state of misalignment, learning of the corresponding sport is relatively awkward. The loss of symmetry is a significant obstacle for carrying out skiing successfully, for example. When suitably adapted wedges 30 are arranged under at least one of the feet of the user, figure 3 shows that the skeleton is perfectly aligned, thus providing the user with a natural satisfactory balance. It is to be understood that this observation is theoretically easy to make but is more difficult to measure in practice when the individual is dressed, when there is no radiographic device available and the time allowed is limited. When a posture correction is made, it is observed that the individual learns the techniques of balance of the desired sport much faster. This is understandable since the individual then only needs to concentrate on problems of disturbance of equilibrium due to carrying out sport activities, rather than additionally having to compensate for their natural disturbance of equilibrium. This is even valid in sports not solely based on equilibrium or balance. In fact, in all cases of forces being exerted, it is preferable to generate these in a symmetrical space. So as to determine the types of posture-correcting wedges to be used, first a calibration is made by using the device of the present embodiment. In practice, the initial muscular tone varies from one individual to another and even more from a child to an adult. To this end, according to the method of the embodiment, the individual picks up the sensor and acts several times on the plunger so as to determine an initial average value of their muscular tone. This preliminary test is carried out by the individual in a natural position and barefoot- on a flat surface which corresponds to a favourable situation with a good muscular tone. Then the test is repeated with an obstacle placed under a foot so as to place the body in an extremely unfavourable situation which then corresponds to a poor muscular tone. According to the appropriate morphology and a predetermined protocol, various wedges for supporting the feet are then successively tested. Generally speaking each wedge or pair of wedges is tested once, by means of a series of at least 10 tests. The user or individual thus exerts the greatest force they can, as fast as they can, 10 successive times, with a time interval between each test to enable the tests to be distinguished by the data acquisition unit. On each pressure, the force exerted and the time taken to exert it are recorded. The user is asked to press using an approximately identical force on the sensor for each of these 10 tests and measurements are carried out. The data acquisition unit calculates a value of F 2 /t for each test, discards the two highest and two lowest values, and then calculates an average of the 6 remaining results. The average value is therefore the output parameter for each wedge or pair of wedges tested. Of course, this particular testing method is a non-restrictive example, but it remains a good compromise between the result obtained and the time required for implementing the method so as to carry out the operation in times compatible with commercial requirements, such as when hiring skis. In general, the weakest force exerted and the shortest time to do so reflect the best muscular tone and thus indicate the best alignment and thus the best-adapted set of wedges. In fact, it has been observed that when the muscular tone is good, the individual's reaction speed is fast and the individual does not feel obliged to exert violent force. In such cases, the force exerted in each test can be very similar, in which case good postural alignment may be assessed by recording the force (pressure) vs. time curve and measuring the slope so as to determine this fast reaction speed synonymous with good muscular tone. This corresponds to well-being and thus to correct alignment since it is the only parameter which varies significantly during testing. In most cases, there are simultaneous variations of the force and speed (time taken to apply the force) because the muscular tone affects both of these two main parameters. So as to determine coefficients (output parameters) which take account of the correlation of these two (measured) parameters, it is advantageous to evaluate a ratio of their values. This can easily be carried out by the microprocessor and/or by the associated computer as described above. For improving measurement, recorded values of the output parameter can be converted into a graph permitting immediate interpretation without the need to read the values. This is advantageous because the values are relative values whose primary purpose is to allow comparisons to between tests to be made. To provide further simplification, it is possible to provide a symbolic or a luminous display for example of the type red/incorrect; green/correct. In kinesiology, provision is generally made to analyse an individual's responses in reaction and not in action. To do this, it is possible to easily modify the sensor by using an inflatable bladder type sensor. In this case, extremely quick inflation of the bladder is required to analyse the reaction of the individual who has the bladder closed in his hand and who is instructed to keep the hand closed and resist the inflation force. This analysis fully conforms to the prescriptions of kinesiology. This inflatable bladder can be replaced by a pneumatic thruster whose response times can be extremely short if it is fed by suitable pressurised gas source. With this reactive embodiment, any possible drifts in the force applied by the individual because of fatigue generated by a succession of tests can be avoided. According to another embodiment, it is possible to use a static sensor 12-1 for measuring the force applied, with its link 14-1 as shown in figure 1 , as opposed to the dynamic sensor 12. In this case, the sensor 12-1 continuously records in the same way the value of the force exerted but without any significant movement of the individual's thumb while the sensor is held in the hand. The advantage is to stop the resisting effort of the return element which facilitates manufacture. Only the force/pressure gauge within the sensor is stressed. The device shown in figure 1 may also be made extremely small and in this case, the link is internal, the sensor and the data acquisition unit being amalgamated into a single housing and being held in the hand. Figure 4 shows a data acquisition block diagram with a summary presentation allowing direct reading of the final information. In figure 4, the block diagram shown in a simplified way illustrates starting with the selection of the number of tests, start-up and verification of the correct connection of the sensor. Then the tests are numbered and recorded to determine the force (pressure) and the speed (time). The ratio is calculated and then the extreme values are eliminated so as to finally determine the average. The method and the sensor described as embodiments are for aligning the support of an individual and this advantageously includes alignment of the whole body. This may involve correction means other than wedges, such as existing devices for correcting the maxillary posture. In all cases, the device of the embodiment may make it possible to determine a state of the person and of his sensations of well-being or otherwise, depending on whether the correction applied to the posture is satisfactory or not.

Claims: CLAIMS 1. Device for determining correct alignment for an individual comprising: - a data acquisition unit coupled to, - a sensor to which the individual can, in use, apply a force such that the data acquisition unit can sense the force exerted by the individual and the time for applying this force, and generate an output parameter therefrom. 2. Device according to claim 1 , in which the sensor is a dynamic sensor for measuring the force exerted by the thumb of the individual on said sensor and the speed used or time taken to apply it or contain it. 3. Device according to claim 1 , in which the sensor is a static sensor (12) held in the hand so as to measure the force exerted by the thumb on said sensor and the speed used or time taken to apply it. 4. Device according to claim 1 , comprising a stimulus means controlled by the data acquisition means for providing a stimulus in reaction to which the individual, in use of the device, exerts the force on the sensor. 5. Method for determining correct alignment for an individual by using the device in any of claims 1 to 4, comprising the following steps: - calibration by carrying out a test using the device to generate an output parameter while the individual adopts a predetermined calibration position, - installing a first of n different alignment accessories, - carrying out a test using the device to generate an output parameter, - installing subsequent alignment accessories and carrying out tests to generate an output parameter corresponding to each of the n alignment accessories, and - comparing the output parameters so as to select the optimum alignment accessory. 6. Method according to claim 5 in which the calibration consists of carrying out at least one test, the individual standing barefoot on a flat surface so as to measure a value corresponding to a proper muscular tone, and at least one test, the individual having one foot on an obstacle so as to measure a value corresponding to an incorrect muscular tone. 7. Method according to claim 5 or 6, in which in each test, with each alignment accessory, the individual is subjected to a plurality of trials, such as 10 trials, to generate a corresponding plurality of output parameter values, the lower and upper extreme values being removed and an average being made of the remaining values to generate the output parameter.

Inventors: CHESNEAU CHRISTIAN PIERRE, CHESNEAU, CHRISTIAN, PIERRE
Applicants: CHESNEAU CHRISTIAN PIERRE, CHESNEAU, CHRISTIAN, PIERRE
Application year: 2001
Main classification: A61B5
IPC codes: A61B5, A63B24, A63B59, A63B69