INJURY REDUCTION INSOLE

Abstract

A footwear-insole for modifying a user's gait configured to extend under a user's foot and provide greater than 0 to 5.0° dorsiflexion support and greater than 0 to 5.0° eversion support.

Claims

1. A footwear-insole for modifying a user's gait, wherein the footwear insole is configured to extend under a user's foot and provide greater than 0 to 5.0° dorsiflexion support and greater than 0 to 5.0° eversion support.

2. A footwear-insole according to claim 1, wherein the insole provides from 0.5° to 3.5° dorsiflexion support, preferably from 1.0° to 3.0° dorsiflexion support, more preferably from 2.0° to 2.5° dorsiflexion support, and yet more preferably about 2.2° dorsiflexion support.

3. A footwear-insole according to claim 1 or 2, wherein the insole provides from 2.0° to 5.0° eversion support, preferably from 3.0° to 5.0°, more preferably from 3.5° to 5.0° eversion support, yet more preferably from 4.0° to 5.0° eversion support, and yet more preferably about 4.5° eversion support.

4. A footwear-insole according to any preceding claim, wherein the insole is configured to be generally foot shaped.

5. A footwear-insole according to any preceding claim, wherein the insole is configured to seat under a user's foot.

6. A footwear-insole according to claim 5, wherein the insole is configured to be inserted into footwear.

7. A footwear-insole according to any preceding claim, wherein the insole extends from the heel to the outer toe of a user's foot, the insole providing a longitudinal and a lateral inclination from an inner heel section of the insole to an outer toe section of the insole to respectively provide dorsiflexion and eversion support.

8. A footwear-insole according to any preceding claim, wherein the insole includes a substantially planar base and a top surface, the longitudinal and the lateral inclination being formed between the base and the top surface of the insole.

9. A footwear-insole according to any preceding claim, wherein the longitudinal inclination and the eversion angle lateral inclination are substantially the same across the entire insole where surface contours are not a substantial factor.

10. A footwear-insole according to any preceding claim, wherein the insole includes the following reference points: A=the most inner medial part of the insole within one fifth of the posterior part of the insole; B=the most inner medial part of the insole within one-fifth of the anterior part of the insole; C=the most outer lateral part of the insole within one-fifth of the posterior part of the insole; and D=the most outer lateral part of the insole within one-fifth of the anterior part of the insole; and wherein the dorsiflexion angle of A to B is approximately equal to the dorsiflexion angle of C to D; and the eversion angle of A to C is approximately equal to the eversion angle of B to D.

11. A footwear-insole according to any preceding claim, further comprising a pair of insoles, a left foot insole and a right foot insole, wherein the dorsiflexion support and eversion support are tailored for each foot of a user.

12. A footwear-insole according to any preceding claim, wherein the insole includes at least one layer of a viscoelastic material, preferably a closed cell foam, more preferably an ethylene vinyl acetate (EVA) foam.

13. A footwear-insole according to any preceding claim, wherein the dorsiflexion support angle is selected to assist with ankle joint dorsiflexion during locomotion.

14. A footwear-insole according to any preceding claim, wherein the eversion support angle is selected to provide improved sideways balance during locomotion.

15. A footwear-insole according to any preceding claim, wherein at least a portion of a top surface of the insole is moulded to fit a user's foot shape.

16. A footwear-insole according to claim 15, wherein the top surface of the insole includes arch support.

17. A footwear-insole according to any preceding claim, wherein the insole includes a top surface including at least one textured section.

18. A footwear-insole according to claim 17, wherein the textured section has a texture height of from 1 mm to 20 mm

19. A footwear-insole according to claim 17 or 18, wherein the textured section has a diameter from 5 mm to 30 mm,

20. A footwear-insole according to any one of claims 17 to 19, wherein the textured sections are configured on the top surface of the insole in at least one of the following configurations: at least two, preferably multiple, textured sections aligned along the CoP path of the insole; at least two parallel lines of multiple textured sections aligned along and with the CoP path of the insole; at least two textured sections located in a Metatarsal region of the insole; or an array of textured sections laterally spread along one lateral half of the insole.

21. A footwear-insole according to any preceding claim, wherein the configuration of the texture sections is different on the insoles of a user's two feet.

22. A method of controlling the gait of a user to reduce the risk of the user falling from or during locomotion comprising providing at least one footwear-insole according to any one of the preceding claims in the user's shoe.

23. A method of modifying the gait of a patient to reduce the risk of falling from or during locomotion, the method comprising: measuring movement of a patient's minimum foot clearance (MFC) to determine a suitable dorsiflexion support angle to enhance ankle joint dorsiflexion and thereby increase swing foot clearance of the patient at MFC during locomotion; measuring lateral movement of a patient's body centre of mass (CoM) during locomotion to determine an eversion support angle which redirects the CoM away from a lateral safety boundary toward the opposite foot; and providing a footwear insole in a user's footwear configured to extend under a user's foot which provides the determined dorsiflexion support angle and eversion support angle, wherein the footwear insole provides greater than 0 to 5.0° dorsiflexion support and greater than 0 to 5.0° eversion support.

24. A method according to claim 23, wherein the footwear insole comprises an insole footwear-insole according to any one claims 2 to 21.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention will now be described with reference to the figures of the accompanying drawings, which illustrate particular preferred embodiments of the present invention, wherein:

[0057] FIG. 1 provides a schematic of a right foot insole according to one embodiment of the present invention showing the inclination of the insole surface of the present invention and points of support dorsiflexion and eversion.

[0058] FIG. 2 provides an example of insole moulding according to one embodiment of the present invention, in which (A) shows an example of moulding to account for an individual's arch-support; and (B) shows an example of the moulded insole surface.

[0059] FIG. 3 provides four examples (A) to (D) of variations of texture installation on an insole according to the present invention which provide enhanced reaction speed.

[0060] FIG. 4 illustrates how dorsiflexion support reduces tripping risks at minimum foot clearance (MFC), showing (A) a schematic of MFC event illustrating the local minimum of vertical swing foot displacement at mid-swing; (B) a plot of the typical swing foot clearance vs swing time; and (C) an illustration of how dorsiflexion support could increase swing foot clearance to avoid obstacle contact.

[0061] FIG. 5 provides an illustration of sideway balance and minimum lateral margin (MLM).

[0062] FIG. 6 provides an illustration of centre of pressure (CoP) control and prevention of inversion ankle sprain by the eversion support, showing (A) a photograph showing an example of inversion ankle sprain; (B) a photograph showing an example of eversion ankle motion; and (C) a schematic illustration of lateral CoP displacement.

[0063] FIG. 7 is an illustration of an embodiment of the insole according to one embodiment of the present invention used for experimental test runs. The insole was 26 cm in length and offers 2.2° dorsiflexion and 4.5° eversion support.

[0064] FIG. 8 illustrates the insole effects on ankle angle (dorsiflexion/plantarflexion) at MFC for young and older adults, dominant and non-dominant limbs separately.

[0065] FIG. 9 illustrates the insole effects on Minimum Foot Clearance (MFC) for young and older adults, dominant and non-dominant limbs separately.

[0066] FIG. 10 illustrates the insole effects on Minimum Lateral Margin (MLM) and lateral Centre of Pressure (CoP) displacement for young and older adults, dominant and non-dominant limbs separately.

[0067] FIG. 11 illustrates the insole effects on recovery rate, time to foot flat and peak knee adduction moment for young and older adults, dominant and non-dominant limbs separately.

[0068] FIG. 12 illustrates the insole effects on foot contact angle at heel contact for young and older adults, dominant and non-dominant limbs separately. Foot contact angle at heel contact is formed by the toe, heel and the floor surface.

[0069] FIG. 13 illustrates the insole effects on basic spatio-temporal gait parameters in young and older adults (effects on dominant and non-dominant limbs have been shown separately).

[0070] FIG. 14 illustrates the insole effects on shank-floor contact angle at heel contact for young and older adults, dominant and non-dominant limbs shown separately.

DEFINITION OF TERMS USED

[0071] Falls in the context here are defined as “inadvertently coming to rest on the ground, floor or other lower level, excluding intentional change in position to rest in furniture, wall or other objects”.

[0072] Tripping is defined as an event in which the most distal feature of the swing limb, usually the lowest part of the shoe or foot, makes unanticipated contact with either the supporting surface or objects on it with sufficient force to destabilise the walker.

[0073] Sideway balance loss is defined when the Centre of mass (CoM) is dislocated lateral to the stance foot's boundary.

[0074] Minimum foot clearance (MFC) is defined as the local minimum of vertical swing foot-ground clearance during mid-swing phase of the gait cycle (FIG. 1).

[0075] Minimum Lateral Margin (MLM) is the event when medio-lateral distance between the CoM excursion and the stance foot is minimum (FIG. 5).

[0076] Centre of Mass (CoM) is the body's centre point in three dimensions determined from the individual body segments' CoM.

[0077] Centre of Pressure (CoP) is the net location of the resultant foot-ground reaction forces on the horizontal plane.

[0078] Stance foot is the foot in contact with the walking surface.

[0079] Swing foot is the foot off the walking surface and travelling forward during normal gait cycle.

DETAILED DESCRIPTION

[0080] The present invention provides a footwear-insole for reducing injuries that may occur when walking, the footwear-insole is configured to extend under a user's foot and provide a range of dorsiflexion (greater than 0 to 5.0°) and eversion support (greater than 0 to 5.0°). The ankle joint supporting functions of dorsiflexion and eversion support for improved gait due to reduced risk of falls and greater mechanical energy efficiency have not been previously applied or tested into footwear-insoles. An insole having both dorsiflexion and eversion support according to the present invention is the first to examine the effects of inclination of the insole interface on optimum gait control.

[0081] A footwear-insole 100, in this case a right foot's insole according to one embodiment of the present invention, is illustrated in FIG. 1. The insole 100 comprises a generally foot shaped element having a planar base 102 and a top surface 104. The top surface 104 is inclined relative to the base 102 to provide the required dorsiflexion support and eversion support. The base 102 provides a flat bottom surface for the insole 100 and the top surface 104 provides an inclined surface on which a user's foot rests and is then angled to provide the requisite dorsiflexion support and eversion support. The insole 100 of the present invention therefore provides a specific incline on the footwear-insole interface to modify ankle joint orientation inside the footwear (for example a shoe). Gait can therefore be controlled in a way that can reduce the risk of tripping and falling.

[0082] Whilst not essential, it is preferred for the inclination of the top surface 104 relative to the base 102 providing the dorsiflexion support and eversion support is substantially constant across the top surface 104 of the insole 100. However it should be appreciated that the dorsiflexion and the eversion angles on the insole 100 surface may vary to slightly to some part of the insole 100 due to such factors as individual-specific foot moulding, arch support, comfort, foot shapes, conditions or the like.

[0083] As shown in FIG. 1, the top surface 104 provides inclination from the inner heel part toward the outer toe to support dorsiflexion and eversion of up to 5 degrees, depending on a wearer's foot condition, comfort and preference. The baseline height at the inner heel varies from 0.1 cm to 3 cm.

[0084] This inclination can be measured relative to specific locations on the insole 100. In the insole 100 shown in FIG. 1 the marked reference locations are: [0085] A=the most inner medial part of the insole 100 within one fifth of the posterior part of the insole 100, [0086] B=the most inner medial part of the insole 100 within one-fifth of the anterior part of the insole 100, [0087] C=the most outer lateral part of the insole within one-fifth of the posterior part of the insole 100, [0088] D=the most outer lateral part of the insole 100 within one-fifth of the anterior part of the insole 100, [0089] P=the most posterior part of the insole 100 top surface 104, [0090] F=the most frontal (anterior) part of the insole 100 top surface 104.

[0091] Both dorsiflexion (α) and eversion (β) angles are in the range, greater than 0° and less than 5°. Dorsiflexion angle (α) of A-B is approximately equal to the angle of C-D; eversion angle (β) of A-C is approximately equal to the angle of B-D. While the same inclination is applied to the entire top surface 104 relative to the base 102, dorsiflexion and eversion angles on the top surface 104 may vary to slightly to some part of the insole 100 due to such factors as individual-specific foot moulding, comfort, foot shapes and conditions.

[0092] The insole 100 may be configured for placement in footwear such as a shoe, boot, or the like as needed (not illustrated). It should be appreciated that the sizing of the insole 100 may vary according to the shape and length of the subject's foot. Furthermore, the appropriate thickness of insole 100 may involve considerations of the footwear type and configuration, activity application (walking, running, sports or the like), patient's age, weight, condition of the knee, ankle, hip and the like. Whilst this should not be considered as being limiting to the present invention, it is noted that in some cases insoles 100 having greater thickness may be desired when participating in sporting activities resulting in higher loads on the body.

[0093] The material of the footwear-insole 100 of the present invention can influence properties of the insole 100 such as elasticity, density, or resilience to maintain the inclination and functions. The insole 100 is therefore preferably formed of a viscoelastic material, preferably a viscoelastic foam. The viscoelastic material can be made at least in part from of any suitable cushioning material with the described properties and characteristics. That is, while the material provides a cushioning it also must retain a wedged shape, even when compressed. Preferably, the material has sufficient durometer (hardness) and possesses a physical memory, meaning that it returns to its original shape after the forces of compression are removed, readying it to accept the impact of the patient's next step and provide cushioning. The viscoelastic material enables the insole 100 to partially collapse under compressive forces and rebound when the compressive forces are removed.

[0094] An example of one suitable viscoelastic material is ethylene vinyl acetate (EVA) foam with its density varying depending on its location under the foot. In preferred embodiments the viscoelastic material is EVA foam or modification thereof. EVA foam provides a plurality of encapsulated gas pockets in the form of closed cells, which when surrounded by the EVA can mimic fatty globules surrounded by fibrous tissue found in the foot. As such, it has been found that EVA foam can be used to mimic the natural anatomical protective structures of the foot. There is a soft thin material covering the surface for comfort and security.

[0095] Moulding technology, or more cost-effective semi-moulding technology can maximise the foot contact area with the interface (e.g. arch-support), and thus foot pressure can be more widely distributed on the insole 100. Various custom-moulding methods can be applied to the top surface of the insole 100 to produce customised fit and support (for example arch support) to the feet of each individual user. This produces an individually moulded insole surface which takes into account each individual's foot shapes including arch-support.

[0096] It should be appreciated that the effects of custom-moulding technology for optimum foot pressure distribution is widely accepted in the art, while dorsiflexion support by orthotics has been also proven to offload the concentration of plantar pressure (for example, Bus, S. A., Ulbrecht, J. S., & Cavanagh, P. R. (2004). Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity. Clinical Biomechanics, 19: 629-638).

[0097] A large number of custom moulding methods are known in the art, including plaster casting or other casting technique, 3D foot scanning, self-moulding methods or the like. It should be appreciated that any number of these well known methods could be used in conjunction with the present invention.

[0098] For example, FIG. 2 illustrates an example of a simple self-moulding method which takes into account an individual's arch-support. Self-moulding materials comprise a shape conforming material such as a thermo-moulding foam or another mouldable material the like, which moulds to a foot shape when pressure and/or heat is applied to an insole 200, for example as shown in FIG. 2(A) which shows the moulding technique. The resulting top surface 204 forms with matching contours to the foot applied to that insole 200, for example as shown in FIG. 2(B) which shows the resulting moulded insole top surface 204.

[0099] Other semi-custom moulding technology can alternatively be used based on a combination of heat-moulding and cryogenic freezing for polymer foams. Moulding can be performed when the material is at a lower density and higher temperature followed by sudden freezing, for example, using liquid nitrogen to fixate the moulded shape semi-permanently, for example as taught in Crabtree, P., Dhokia, V. G., Newman, S. T., & Ansell, M. P. (2009). Manufacturing methodology for personalised symptom-specific sports insoles. Robotics and Computer-Integrated Manufacturing, 25: 972-979.

[0100] As previously noted, the top surface of the insole 100 (foot to insole interface) can be textured to provide a greater tactile sensation and thus enhance reaction speed/feedback to user. Use of a textured surface on the footwear-insoles 100 can stimulate cutaneous receptors on the bottom of the foot and may improve movement control. It should be appreciated that texture installation on the CoP path has been previously reported to effectively enhance afferent feedback by providing greater tactile sensation for cutaneous receptors that are aligned on the typical CoP path (for example Nurse, M. A., & Nigg, B. M. (2001). The effect of changes in foot sensation on plantar pressure and muscle activity. Clinical Biomechanics, 16: 719-727).

[0101] FIG. 3 provides four examples of texture installation 310A, 310B, 310C and 310D applied to an insole 300A, 300B, 300C 300D of the present invention for enhanced reaction speed. As shown in FIG. 3A, each texture installation 310A, 310B, 310C and 310D comprises multiply arranged texture elements 312 which comprise a circular area of textured material. Each texture element 312 has a texture specification based on height (1 mm to 20 mm) and diameter (5 mm to 30 mm). As should be appreciated, the exact specification would be selected to suit an individual's foot condition and the level of sensation to be produced. Similarly, the number of texture elements 312 used, spacing between multiple texture elements 312 and diameter or material of a texture element 312 determines the level of tactile sensation required for different individuals. As is understood in the art, various plastic, rubber and/or wooden materials could be used to enhance or maintain the functionality of a texture element 312. The fundamental concept is to stimulate cutaneous receptors to promote afferent feedback for quicker reaction. The illustrated texture installation 310A, 310B, 310C and 310D in FIG. 3 are as follows:

[0102] FIG. 3A shows texture installation 310A (Version 1) comprising an orthodox type with multiple texture elements 312 installed or mounted along with the CoP path 314.

[0103] FIG. 3B shows texture installation 310B (Version 2) comprising a dual installation (two parallel spaced apart lines of multiply aligned texture elements 312) extending along with the CoP path 314. The dual installation texture elements 312 strengthen the response sensation to a user.

[0104] FIG. 3C shows texture installation 310C (Version 3) comprising multiple texture elements 312 installed or mounted along with the CoP path 314 with a concentration of texture elements 312 in the Metatarsal region 315 of the insole. This texture installation 310C accentuates tactile sensation at metatarsal region 315 in case dorsiflexion support reduces sufficient afferent feedback.

[0105] FIG. 3D shows texture installation 310D (Version 4) comprising multiple texture elements 312 installed or mounted in an array 316 on one lateral side of the CoP path 314. This texture installation 310D is advantageous for lateral balance loss prevention to activate greater cutaneous sensation when CoP is dislocated more laterally. Version 4 aims to activate tactile sensation when CoP is laterally deviated designed particularly for prevention of sideway balance disturbance.

[0106] It should be appreciated that the texture installation on an insole 100, 200, 300A to 300D may differ between the two feet depending on tactile sensitivity. Thus, the present invention can be used to overcome any unwanted asymmetry by adopting different modifications on each side of footwear-insole 100, 200, 300A to 300D.

[0107] Examples of some of the various applications and functions of the insole of the present invention will now be discussed:

Prevention of Tripping Risk at Minimum Foot Clearance (MFC) by Dorsiflexion Support

[0108] The insole of the present invention can reduce the occurrence of tripping, particularly tripping risks at minimum foot clearance (MFC).

[0109] FIG. 4 provides three FIGS. 4A to 4C) which demonstrate how dorsiflexion support of the insole of the present invention reduces tripping risks at minimum foot clearance (MFC). FIG. 4(A) shows an illustration of the movement of the MFC: the local minimum of vertical swing foot displacement at mid-swing. As illustrated, tripping is defined as an unexpected contact of a swing foot with a walking surface or an obstacle on it with the sufficient force that destabilises a walker. Minimum foot clearance (MFC) is a crucial part of a walking cycle with very low vertical clearance (˜1 to 2 cm). To prevent tripping, higher swing foot clearance is critical, and ankle dorsiflexion has been identified as the most effective primary lower limb joint motion that increases swing foot clearance at MFC. As shown in FIG. 4(C), dorsiflexion support provided by an insole of the present invention can increase swing foot clearance.

Improvement of Sideways Balance

[0110] The insole of the present invention can improve sideways balance of a user when walking.

[0111] As illustrated in FIG. 5, lateral balance loss can be measured by recording the CoM movement lateral to the foot in contact with the walking surface (i.e., support foot boundary). In this Figure, AP=anterior-posterior; ML=medio-lateral. MLM=minimum medio-lateral distance between the Centre of Mass (CoM) and stance foot toe-heel line during the walking cycle. Minimum lateral margin (MLM) is defined when the CoM reaches the lateral safety boundary, defined by the line between the stance foot's toe and heel (for example as discussed in Nagano, H., Begg, R., and Sparrow, W. A. 2013. Ageing effects on medio-lateral balance during walking with increased and decreased step width. In proceedings of the 35th International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS), IEEE. Osaka, Japan, 3-7 Jul. 2013). Sideways balance loss is defined when MLM is less than 0.

[0112] Eversion support of the insole of the present invention can assist CoM redirection away from the lateral safety boundary toward the opposite foot thereby increasing MLM to minimise sideways balance loss.

Centre of Pressure (COP) Control by Eversion Support

[0113] The insole of the present invention can improve center of pressure control of a user when walking.

[0114] As illustrated in FIG. 6A an ankle inversion sprain 420 can lead to severe acute injuries such as ruptures of joint ligaments and it also can cause loss of sideways balance. This occurs when the foot's CoP displacement deviates excessively to the lateral direction. FIG. 6B shows related eversion ankle motion.

[0115] Eversion support of the insole of the present invention can help to regulate lateral CoP displacement, and control the CoP path 412 of a user's foot 400 as shown in FIG. 6C.

Greater Mechanical Energy Efficiency During Loading Response

[0116] The insole of the present invention can improve mechanical energy efficiency, which may be useful for relieving conditions such as lower limb joint osteoarthritis.

[0117] Impact generated by foot strike can be partially oscillated to the opposite foot and can be utilised for the opposite foot's toe-off. The percentage of mechanical energy oscillation can be described by an established computational method to calculate recovery rate as indicated below. A more efficient loading response accompanies reduced impact transferred to lower limb joints.

Recovery rate (%)=100*[ΔKE+ΔPE−Δ(TEc)]/(ΔKE+ΔPE)

where ΔPE/ΔKE/ΔTEc indicate positive increase in mechanical energy of CoM during double support phase of gait cycle; PE is potential energy, KE is kinetic energy, TEc is the sum of KE and PE.

[0118] A dorsiflexed ankle at heel contact can stretch the Achilles tendon and absorb impact as elastic energy, which is later released toward opposite toe-off for maximum mechanical energy efficiency. More dorsiflexed heel contact, as provided by the insole of the present invention, also prolongs time to foot flat, which is biomechanically advantageous in dissipating peak force over longer period of time. Eversion support from the insole of the present invention can also facilitate the natural loading of a foot immediately following heel contact.

Foot Pressure Distribution

[0119] The insole of the present invention can modify and/or improve foot pressure distribution of a user when walking.

[0120] Foot pressure distribution is possible by (semi) moulding of the insole surface to maximise the contact area with the foot (e.g., arch-support), as for example described above for the insole of the present invention. Dorsiflexion support provided by the insole of the present invention can also shift the concentration of foot pressure to the posterior direction, to move the pressure away from the common site of ulcer development.

Other Effects of Dorsiflexion and Eversion on Walking Patterns

[0121] Ankle joint motions supported by footwear-insole intervention will not change walking patterns to the extent where other associated gait problems may arise. In other words, the insole of the present invention is to control fine-ankle joint movement only by a small amount (i.e., less than 1 cm increase in MFC) without making any dramatic changes to natural walking patterns. Addition of dorsiflexion up to 5° has been reported to cause no substantial effects on joint moments and fundamental step cycle spatio-temporal gait parameters.

EXAMPLES

[0122] A combination of dorsiflexion and eversion has been applied to an experimental/test insole 500 (FIG. 7) to examine effects of combined joint motions on minimising tripping and lateral balance loss risks and enhanced stance foot loading and reduced impact transferred to the knees. The insole effects were also examined to confirm these ankle joint modifications would not cause fundamental changes to the gait patterns.

[0123] The experimental footwear-insole 500 is illustrated in FIG. 7. The experimental/tested footwear-insoles 500 were designed to support 2.2° dorsiflexion and 4.5° eversion at the static standing position provided by an incline between a planar base 502 and planar top surface 504 of the insole 500.

[0124] The exact dimensions of each experimental insole 500 varied in accordance with the size of the test subject's feet. The insole 500 was sized to fit the general shoe size of each test subject's feet. In an example of the 26 cm footwear-insole (FIG. 7), relative to the baseline height at the inner heel=0 cm (point A in FIG. 7), the most outer heel edge (point C in FIG. 7) was 0.5 cm higher and this eversion angle was applied across the entire insole surface. The most anterior inner surface, the inner toe (point B in FIG. 7) was elevated relative to the inner heel by 1.0 cm and the highest section was, accordingly, the most lateral and anterior toe section (point D in FIG. 7) at 1.5 cm higher to maintain the ankle joint angles.

[0125] A total of 30 young (18 to 35 yrs.) and 26 healthy older adults (>65 yrs.) participated in gait testing wearing both the flat shoe insole and the experimental insole 500, both the dominant and non-dominant limbs were tested separately. A total of 60 to 90 gait cycles were collected from both lower limbs of every participant per insole condition.

[0126] The results of the investigation is summarised in subsections below. All the noted differences were qualified as statistically significant.

Tripping Risk Minimisation

[0127] The tested insoles with 2.2° dorsiflexion and 4.5° eversion support at static standing increased dorsiflexion by 0.7° at MFC (FIG. 8) and elevated swing foot clearance by 0.36 cm (FIG. 9), a remarkable increase in swing foot clearance for tripping risk minimisation.

Improving Sideways Balance

[0128] In combination with dorsiflexion, 4.5° eversion support regulated lateral movement of the CoM and reduced MLM by 0.75 cm (FIG. 10).

Prevention of Inversion Sprain

[0129] CoP lateral displacement was reduced by 0.63 cm wearing the tested insoles, therefore lower risks of inversion sprain and associated lateral balance loss (FIG. 10).

Energy Efficient Loading Response and Reduced Risks of Knee Osteoarthritis

[0130] A combination of dorsiflexion and eversion enhanced mechanical energy efficiency at heel contact, confirmed by 2% increase in recovery rate (FIG. 11). In addition, the insole increased foot contact angle especially for the older adults by greater than 2° (FIG. 12) and time to foot flat from heel contact was prolonged by 0.015 s (FIG. 11). A combination of these effects reduced impact transferred to lower limb joints, reflected in more than 20% reduction in knee adduction moment (FIG. 11).

Gait Patterns not Affected by the Tested Insole

[0131] The tested insole did not change step velocity, length and double support time (FIG. 13). The tested insole did not have any effects on shank-floor contact angles (FIG. 14), an implication for not negatively increasing slipping risks.

[0132] It should be appreciated that the application of all the biomechanical modifications of the present invention on footwear-insoles is the standard recommendation to maximise the benefits. Inclination angles of the footwear-insole interface due to dorsiflexion and eversion can vary. The insole of the present invention may therefore include some but not all of the features discussed above. For example, the discussed moulding or semi-moulding and various sizes, number, diameters and materials of textures are optional features which can be included where considered useful or advantageous. For example, texture installation is to be avoided in the presence of, for example, foot ulcer. Arch-support is not applicable for a foot without an arch.

[0133] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention.

[0134] Where the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other feature, integer, step, component or group thereof.