Abstract
Background: Footwear, orthoses, and insoles have been shown to influence balance in older adults; however, it remains unclear which features, singular or in combination, are considered optimal. The aim of this scoping review was to identify and synthesise the current evidence regarding how footwear, orthoses, and insoles influence balance in older adults. Four electronic databases (MEDLINE, CINAHL, Embase, and AMED) were searched from inception to October 2023. Key terms such as “shoe*,” “orthoses,” “postural balance” and “older people” were employed in the search strategy. Studies meeting the following criteria were included: (i) participants had a minimum age ≥60 years, and were free of any neurological, musculoskeletal, and cardiovascular diseases; (ii) an active intervention consisting of footwear, foot orthoses, or insoles was evaluated; and (iii) at least one objective outcome measure of balance was reported. Summary: A total of 56 studies from 17 different countries were included. Three study designs were utilised (cross-sectional study, n = 44; randomised parallel group, n = 6; cohort study n = 6). The duration of studies varied considerably, with 41 studies evaluating immediate effects, 14 evaluating effects from 3 days to 12 weeks, and 1 study having a duration of 6 months. Seventeen different interventions were evaluated, including/consisting of textured insoles (n = 12), heel elevation (n = 8), non-specific standardised footwear and changes in sole thickness or hardness (n = 7 each), sole geometry or rocker soles, contoured or custom insoles and high collar height (n = 6 each), insole thickness or hardness and vibrating insoles (n = 5 each), outsole tread (n = 4), minimalist footwear and slippers (n = 3 each), balance-enhancing shoes, footwear fit, socks, and ankle-foot orthoses (n = 2 each), and eversion insoles, heel cups, and unstable footwear (n = 1 each). Twenty-three different outcomes were assessed, and postural sway was the most common (n = 20), followed by temporo-spatial gait parameters (n = 17). There was uncertainty regarding intervention effectiveness. Overall, features such as secure fixation, a textured insole, a medium-to-hard density midsole and a higher ankle collar, in isolation, were able to positively impact balance. Conversely, footwear with an elevated heel height and the use of socks and slippers impaired balance. Key Messages: There is a substantial body of literature exploring the effects of footwear, orthoses, and insoles on balance in older adults. However, considerable uncertainty exists regarding the efficacy of these interventions due to variability in methodological approaches. Further high-quality research is necessary to determine whether a singular intervention or a combination of interventions is most effective for enhancing balance in older adults.
Introduction
Falls in older adults are highly prevalent and are a leading cause of injury and injury related death [1, 2]. Estimates suggest that more than 420,000 fatal falls occur in older adults each year globally, with approximately one in three community dwelling older adults falling per annum [3, 4]. Furthermore, falls can have a significant negative impact on the quality of life in older adults, resulting in social isolation, anxiety, depression, and prolonged hospitalisation [5]. By 2050, it is projected that older adults will constitute 23% of Australia’s population, with a similar trend expected in other developed countries [6]. Given this projection, and the consistently high rate of falls, the burden on the broader healthcare system is likely to be substantial [7].
Numerous risk factors for falls in older adults have been identified, including medical conditions such as stroke and Parkinson’s disease, use of psychoactive medications, sensory and neuromuscular factors (reduced vision, peripheral sensory loss, and muscle weakness), and balance disturbances resulting from age-related decline [8]. Footwear, orthotic devices, and insoles are modifiable factors that have been shown to influence balance performance and gait patterns in older individuals [9‒11]. While certain footwear features, such as elevated heels have been shown to adversely affect balance [9], others, such as a high collar, lower heel height, thin and firm midsole, and slip resistant outer sole with tread, have been shown to be beneficial for improving balance [12]. Healthcare practitioners have been advised to promote the use of shoes that incorporate these balance-enhancing features. However, it is unclear whether these recommendations remain valid in light of recent research findings. Furthermore, there is also uncertainty regarding which of these shoe features, orthoses, and insoles, whether used in isolation or in combination, exert the most positive influence on balance in older adults.
Systematic reviews published previously have explored the effects of insoles alone or the effects of orthotics combined with specific shoe features on balance in older adults [11‒13]. However, more recent studies have been published, prompting the need for this updated review. Therefore, the aim of this scoping review was to identify and synthesise the current evidence examining the effects of footwear, orthoses, or insoles on balance in older adults, with a view to identifying which features, in isolation or in combination, exert the most positive impact.
Methods
Search Strategy
All review authors contributed to identifying key terms to identify the relevant literature. Four electronic databases were searched from inception to October 15, 2023. One review author (A.N.A.) developed the full search strategy for MEDLINE, CINAHL, Embase, and AMED in consultation with a university librarian. Search terms were categorised into three concepts and tailored for each database: (i) footwear/orthoses/insoles, (ii) balance/stability/postural sway, and (iii) older adults. For each database, search terms included keywords and mapped subject headings. Keywords used within each concept were combined with “OR” and between concept results were combined with “AND.” The full search strategy is provided in online supplementary file 1 (for all online suppl. material, see https://doi.org/10.1159/000539591). Screening of the titles and abstracts was completed by two independent reviewers (A.N.A. and H.B.M.) for eligibility against the inclusion/exclusion criteria for the review. Any conflicts regarding a study’s appropriateness were resolved at a consensus meeting between the original two reviewers.
Study Selection and Screening
To be included, studies needed to include participants aged 60 years or older who could ambulate independently without the use of a walking aid, evaluate at least one intervention pertaining to footwear, orthoses, or insoles, and report at least one objective measure of balance (e.g., Timed Up and Go Test, Functional Reach Test, or temporo-spatial measures). Publications were excluded if the studies included participants who had conditions which could impact balance (diabetes, Parkinson’s disease, or stroke); were published in a language other than English full text; were systematic reviews, scoping reviews, conference proceedings, or abstracts. Full-text screening was performed independently by two review authors (A.N.A. and H.B.M.). Disagreements regarding a study’s eligibility for the review were resolved at a consensus meeting between the two review authors.
Data Extraction
Data extraction was completed by one review author (A.N.A.) using a custom generated extraction template created in Covidence (Covidence, Melbourne, Australia), with another review author (H.B.M.) confirming the data extracted. Characteristics extracted using the custom template included lead author, country, study design, method of recruitment, number of participants, mean age of participants, reported outcome measures, interventions and active comparators, results from latest time point and summary of findings. After the initial data extraction was completed, A.N.A. and H.B.M. resolved any disagreements to finalise extraction for each study during an additional meeting. The full item extraction tool is provided in online supplementary file 2.
Results
The initial search across all four databases yielded 1,712 records. Duplicates were removed leaving 1,120 records for title and abstract screening. Following this, 1,019 records were excluded with an additional 45 articles excluded after full-text screening. A total of 56 studies were included in the review. Figure 1 depicts the PRISMA flowchart for the included studies.
Characteristics of Included Studies
Tabulated data of included study characteristics is shown in Table 1. Studies included in this review originated from 17 different countries: 13 (23.2%) studies originated from Australia [16‒28], 10 (17.9%) from the USA [29‒38], eight (14.3%) from China [39‒46], five (9%) from Canada [47‒51], three (5.4%) from Iran [52‒54], two each from the UK [55, 56] (3.6%), New Zealand [57, 58] (3.6%), Germany [59, 60] (3.6%) and Turkey [61, 62] (3.6%), one each from Japan [63] (1.8%), Brazil [64] (1.8%), Ireland [65] (1.8%), Belgium [66] (1.8%), Norway [67] (1.8%), Spain [68] (1.8%), France [69] (1.8%), Switzerland [70] (1.8%), and Thailand [71] (1.8%).
Study characteristics
| Characteristics | n (%) |
|---|---|
| Study design | |
| Cross-sectional study | 44 (78.6) |
| Cohort study | 6 (10.7) |
| Random parallel group | 6 (10.7) |
| Country | |
| Australia | 13 (23.2) |
| USA | 10 (17.9) |
| China | 8 (14.3) |
| Canada | 5 (9.0) |
| Iran | 3 (5.4) |
| UK | 2 (3.6) |
| New Zealand | 2 (3.6) |
| Germany | 2 (3.6) |
| Turkey | 2 (3.6) |
| Ireland | 1 (1.8) |
| Brazil | 1 (1.8) |
| Belgium | 1 (1.8) |
| Norway | 1 (1.8) |
| Thailand | 1 (1.8) |
| Spain | 1 (1.8) |
| Switzerland | 1 (1.8) |
| Japan | 1 (1.8) |
| France | 1 (1.8) |
| Duration of study | |
| Immediate effects (within session) | 41 (73.2) |
| Three to seven days | 3 (5.4) |
| Two weeks | 1 (1.8) |
| Three weeks | 1 (1.8) |
| Four weeks | 4 (7.1) |
| Five weeks | 1 (1.8) |
| Six weeks | 1 (1.8) |
| Eight weeks | 1 (1.8) |
| 12 weeks | 2 (3.6) |
| Six months | 1 (1.8) |
| Characteristics | n (%) |
|---|---|
| Study design | |
| Cross-sectional study | 44 (78.6) |
| Cohort study | 6 (10.7) |
| Random parallel group | 6 (10.7) |
| Country | |
| Australia | 13 (23.2) |
| USA | 10 (17.9) |
| China | 8 (14.3) |
| Canada | 5 (9.0) |
| Iran | 3 (5.4) |
| UK | 2 (3.6) |
| New Zealand | 2 (3.6) |
| Germany | 2 (3.6) |
| Turkey | 2 (3.6) |
| Ireland | 1 (1.8) |
| Brazil | 1 (1.8) |
| Belgium | 1 (1.8) |
| Norway | 1 (1.8) |
| Thailand | 1 (1.8) |
| Spain | 1 (1.8) |
| Switzerland | 1 (1.8) |
| Japan | 1 (1.8) |
| France | 1 (1.8) |
| Duration of study | |
| Immediate effects (within session) | 41 (73.2) |
| Three to seven days | 3 (5.4) |
| Two weeks | 1 (1.8) |
| Three weeks | 1 (1.8) |
| Four weeks | 4 (7.1) |
| Five weeks | 1 (1.8) |
| Six weeks | 1 (1.8) |
| Eight weeks | 1 (1.8) |
| 12 weeks | 2 (3.6) |
| Six months | 1 (1.8) |
The included studies utilised three primary study designs: cross-sectional study design was utilised in 44 different studies [16‒32, 35‒37, 39, 40, 42‒44, 46‒48, 50‒52, 54‒58, 60, 61, 63, 65‒69], randomised parallel group [38, 49, 53, 64, 70, 71] and cohort study designs [33, 34, 41, 45, 59, 62] were employed by six studies, respectively.
The studies also varied in their duration: 41 studies reported immediate effects (defined as within session) [16‒23, 25‒32, 35, 36, 39, 40, 42‒44, 46‒48, 50‒52, 54‒58, 60, 62, 63, 65‒67, 69], three studies reported effects over three to 7 days [37, 45, 68], one study reported effects over 2 weeks [24] and 3 weeks [61], respectively, four studies reported effects over a 4-week period [34, 53, 64, 71], one study was conducted 5 weeks [59], 6 weeks [33], and 8 weeks [41] each, two studies were completed over 12 weeks [49, 70], and one study extended to 6 months [38].
Interventions
Studies included in this scoping review utilised 17 different interventions. Textured insoles were the most commonly used intervention, reported in 12 studies [23, 39, 43, 44, 49, 51, 52, 54, 58, 64, 69, 70]. Eight studies included a form of heel elevation change to footwear [16, 18‒22, 59, 66], followed by non-specific standardised footwear [29, 30, 46, 57, 60, 65, 66], changes in sole thickness or hardness [17‒22, 48] (seven studies each), sole geometry or rocker soles [18‒21, 47, 56], contoured or custom insoles [33, 34, 39, 42, 45, 52], high collar height [17‒22] (six studies each), insole thickness or hardness [23, 39, 50, 61, 68], vibrating insoles [31, 32, 35, 37, 40] (five studies each), outsole tread (four studies [18‒21]), minimalist footwear [26, 55, 67] and slippers [25, 63, 66] (3 studies each), balance-enhancing shoes (defined as footwear that in cooperates features that have been previously shown to improve balance [26]) [26, 28], footwear fit [62, 63], socks [42, 71], and ankle-foot orthoses [36, 38] (two studies each), and eversion insoles (defined as a device which was designed to promote dorsiflexion and eversion through the ankle joint) [27], heel cups [41], and unstable footwear [53] (one study each). A table presenting the intervention(s) for each study can be found in online supplementary file 3.
Outcome Measures
Included studies utilised 23 different outcome measures, with some studies investigating multiple outcome measures. Postural sway was the most commonly reported outcome measure, reported in 20 studies [16, 17, 20, 23, 25, 26, 28, 31, 36‒44, 49, 54, 55, 57, 59, 61, 68, 69], closely followed by temporo-spatial gait parameters (e.g., speed, cadence, stance time, swing time), reported in 17 studies [18, 19, 21, 22, 24‒27, 32, 35, 37, 38, 43, 45‒47, 50, 53, 55, 56, 58‒60, 63, 66, 67, 69‒71]. Other reported outcome measures included the Timed Up and Go Test (nine studies [30, 33, 36, 37, 47, 54, 55, 62, 64]), minimum foot clearance (five studies [24, 27, 56, 60, 63]), the Berg balance scale (four studies [33, 62, 64, 65]), maximal balance range (three studies [16, 17, 20]), coordinated stability (three studies [16, 17, 20]), the star excursion balance test (two studies [52, 55]), one legged stance test (two studies [29, 34]) and the functional reach test (two studies [30, 36]). The 180° turn test [47], perturbation protocol [47], Mini-Balance Evaluation Systems Test [71], modified 30 s chair stand test [71], percentage of stepping reactions involving “extra” reactions (forward, backward, lateral, combined steps) [51], choice stepping reaction time [20], sharpened Romberg test [29], balance failure frequency [48], 10 m walk test [30], tandem gait test [34], tandem stance test [34], step test [34], and the Fullerton Advanced Balance Scale [53] were reported as an outcome measure in one study each. A summary of the outcome measure(s) for each study is reported in online supplementary file 3.
The primary findings from the included studies indicate that footwear characterised by secure fixation, a firm-to-hard midsole, and a high ankle collar, when used individually, positively impact balance performance in older adults. Devices such as textured and contouring insoles have also been shown to improve balance. However, shoes with elevated heels, socks, and slippers have a detrimental impact balance in older adult populations. Table 2 summarises the findings and implication for each intervention(s).
Findings and recommendations
| Intervention | Findings | Recommendations |
|---|---|---|
| Non-standardised footwear | Arnnadottir [30], Horgan [65], and Brenton-Rule [57] found wearing non-standardised footwear improved balance performance compared to barefoot conditions. De Mettelinge [66] found no differences between non-standardised footwear and other active comparators, although the barefoot condition was detrimental. Briggs [29] and Hollander [60] reported no differences between non-standardised footwear and barefoot conditions. Ren [46] found the barefoot condition to be superior compared to the footwear condition for perturbation-based performance | Due to differences in the type of footwear used in these studies, it is difficult to determine whether non-standardised footwear is beneficial or detrimental to balance in this population |
| Ankle-foot orthoses (AFOs) | Yalla [36] and Wang [38] reported that use of AFOs resulted in improved performance in postural sway in older adults. Wang [38] found that long-term use of AFOs reduces intrinsic fear of falling in older adults | AFOs have been found to improve balance in older adults, however due to the design of AFOs, some older adults may find the device too awkward and unappealing to use on a daily basis |
| Balancing-enhancing footwear | Menz [26] and Nor Azhar [28] found little to no difference in most of the outcome measures when compared to minimalist shoes and participants own footwear. However, Menz [26] reported the balance-enhancing footwear significantly reduced step width and end sway compared to the minimalist footwear condition | Further studies need to be undertaken to determine whether balance-enhancing shoes are preferable to minimalist shoes or participants’ own footwear, and whether function can be maintained while making the shoe more aesthetically pleasing |
| Footwear fit | Maden [62] and Hida [63] found balance performance increased when wearing appropriately fitting footwear compared to ill-fitting fitting footwear conditions. Hida [63] also found that ill-fitting footwear increases knee and ankle joint variability while walking in older adults which may be a risk factor for falls | Older people should wear shoes that fit appropriately, as ill-fitting shoes appear to pose an unnecessary balance hazard |
| Heel elevation | Lord [16] and Menant [18, 20] reported that footwear with an elevated heel (6 cm) impaired balance performance in older adults. Menant [19, 22] also found that older adults wearing higher heeled shoes employed a more conservative walking gait and also reported that pelvic acceleration in the mediolateral direction was reduced compared to other footwear conditions, suggesting a mechanical compensatory strategy to mitigate mediolateral instability from heel elevation. Menant [21] and de Mettelinge [66] reported footwear with elevated heels made no significant to walking stability performance. Lindemann [59] suggested that changes to heel height in different shoe conditions results in minimal differences if the heel elevation is below a critical value | Heel elevation in footwear can be detrimental to balance in older adults |
| Higher collar cut | Lord [17] and Menant [18, 20, 21] found higher collared footwear to be beneficial to balance in older adults. Menant [18, 21] also found higher collared footwear produced a significant reduction in total stopping time on wet surfaces and significant differences in toe clearance, double-support time and step width compared to the control condition. Two studies from Menant [19, 22] also reported that higher collared footwear did not change any temporo-spatial gait parameters during standing or walking compared to the control condition | Footwear with a higher collar may improve balance in older adults |
| Textured insoles | Qiu [23], Li [43], Huang [44], Perry, Maki [51], Kiaghadi [52], Asgari [54], de Morais Barbosa [64], and Palluel [69] all reported positive outcomes when older adult participants wore textured insoles compared to other conditions. Kiaghadi [52] concluded that older adults wearing textured insoles had a shorter reach length in three directions when completing the star excursion balance testa. Qu [39], Hatton [58], and Hartmann [70] however, found no difference in balance performance | While there appears to be some benefit in the addition of textured insoles, the optimum design and placement of the texture needs further study |
| Custom or contoured insoles | Mulford [33], Gross [34], Qu [39], Ma [42], Peng [45], and Kiaghadi [52] indicate that custom or contoured insoles are beneficial for balance when standing or walking. Kiaghadi [52] concluded that older adults wearing textured insoles had a shorter reach length in three directions when completing the star excursion balance testa | Custom or contoured insoles may improve balance in older adults |
| Vibrating insoles | Priplata [31], Galica [32], Stephen [35], Lipsitz [37], and Wang [40] found that insoles applying vibratory stimulation to the plantar surface of the foot in older adults increased balance performance | Vibrating insoles may improve balance performance in older adults, however, the issue of practicality of this intervention needs to be considered |
| Insole thickness or hardness | Qiu [23] and Iglesias [68] suggest that postural sway performance increased when wearing either hard or soft insoles compared to the barefoot condition. Buyukturan [61] reported that an insole with a thickness of 10 mm was optimal to improve static postural sway in older adults with a history of falls. Qu [39] found no evidence to suggest that either a soft or rigid insole improved balance performance in older adults, while Antontio [50] determined that changes to insole density did not significantly impact balance during stair-descent | Further research is required to understand which insole thickness and density is most beneficial to balance performance |
| Eversion insole | Nagano [27] found that insoles which promote dorsiflexion and eversion through the ankle joint can increase minimum foot clearance in older males, potentially reducing the risk of falls when compared to wearing no insoles | Due to limited research regarding eversion insoles, further research is required to determine the effect of this intervention on balance in older adults |
| Heel cups | Chen [41] reported that heel cups designed with an arch contouring device significantly improved standing balance performance in older adults. It is important to note, that this study did not have an active comparator and only assessed changes over time | Due to limited research involving heel cups, further research is required to determine the effect of this intervention on balance in older adults |
| Changes in midsole thickness or hardness | Menant [20] and Robbins [48] both noted that balance performance in older adults was improved when footwear incorporated a hard midsole (Shore A-58 and Shore A-50, respectively). Menant [18] reported footwear with a medium density midsole (Shore A-40) improved stability on various surfaces in older adults compared to the same shoe with various modifications (elevated heel, soft sole, hard sole, flared sole, bevelled heel, high collar, and tread outsole). Menant [18, 19, 21] and Robbins [48] found softer soles to be detrimental to balance performance compared to harder soled comparators. Menant [19] also reported minimal difference in balance performance between a medium density midsole shoe (Shore A-40), and a harder density midsole shoe (Shore A-58) over a range of surfaces. Lord [17] and Menant [22] saw no change in balance performance in older adults when changing the density of the midsole of footwear | A firm or hard midsole is beneficial for balance performance in older adults, while a softer density midsole may pose a risk for falls |
| Sole geometry or rocker soles | Takeshi [47] reported that increasing sole width of footwear improved lateral stability in older adults. Thies [56] found that by increasing the degree of the forefoot rocker, minimum toe clearance in older adult participants also increased. Menant [18, 20, 21] also found negligible differences in footwear that included either a flared or bevelled heel block compared to the control and other active comparator conditions | Further research is required to determine which modification to sole geometry is most effective |
| Outsole tread | Menant [18‒21] found that shoes with an outsole tread were neither beneficial nor detrimental to balance performance compared to the control conditions, suggesting that shoes with an outsole tread may be worthy of consideration as they do not seem to impair balance performance | Outsole tread did not impact balance, however it is likely to influence slipping in wet conditions [72‒74] and should therefore be a consideration in older adults |
| Minimalist footwear | Cudejko [55] reported that older adults with a history of falls had better performance in the Timed Up and Go and star excursion balance tests when in minimalist shoes compared to conventional footwear and barefoot condition, while Petersen [67] found minimalist shoes to increase local dynamic stability and reduce minimum toe clearance variability in older adults. However, Menz [26] found minimalist shoes to have no effects on temporo-spatial parameters in older women when compared to the control and comparator conditions | Minimalist footwear may improve balance performance on level surfaces in the short-term; however, for longer periods of time and on more challenging terrain, minimalist footwear may become uncomfortable for older adults |
| Slippers and socks | Hida [63] and de Mettelinge [66] found balance performance in older adults was not impacted by the use of slippers compared to other comparator conditions. However, Menz [25] found that slippers incorporating an enclosed heel and Velcro fixation enhanced balance performance in older women compared to slippers with an open-back heel. Pinvaninchkul [71] reported socks with a textured footbed was deemed to be beneficial for balance compared to a standard sock alone, while Ma [42] found postural sway performance was worse when older adults wore socks only, compared to barefoot and socks plus insole conditionsb | While slippers and socks are accessible options for older adults especially for indoor settings, older adults are more likely to fall indoors when wearing slippers or socks [75]. Therefore, it would be appropriate to advise older adults to wear shoes indoors |
| Unstable footwear | Sobhani [53] reported improved performance in the Fullarton Advanced Balance Scale, maximum and preferred gait speed in the unstable footwear condition compared to the stable footwear condition | Due to limited research involving unstable footwear, further research is required to determine the effect of this intervention on balance in older adults |
| Intervention | Findings | Recommendations |
|---|---|---|
| Non-standardised footwear | Arnnadottir [30], Horgan [65], and Brenton-Rule [57] found wearing non-standardised footwear improved balance performance compared to barefoot conditions. De Mettelinge [66] found no differences between non-standardised footwear and other active comparators, although the barefoot condition was detrimental. Briggs [29] and Hollander [60] reported no differences between non-standardised footwear and barefoot conditions. Ren [46] found the barefoot condition to be superior compared to the footwear condition for perturbation-based performance | Due to differences in the type of footwear used in these studies, it is difficult to determine whether non-standardised footwear is beneficial or detrimental to balance in this population |
| Ankle-foot orthoses (AFOs) | Yalla [36] and Wang [38] reported that use of AFOs resulted in improved performance in postural sway in older adults. Wang [38] found that long-term use of AFOs reduces intrinsic fear of falling in older adults | AFOs have been found to improve balance in older adults, however due to the design of AFOs, some older adults may find the device too awkward and unappealing to use on a daily basis |
| Balancing-enhancing footwear | Menz [26] and Nor Azhar [28] found little to no difference in most of the outcome measures when compared to minimalist shoes and participants own footwear. However, Menz [26] reported the balance-enhancing footwear significantly reduced step width and end sway compared to the minimalist footwear condition | Further studies need to be undertaken to determine whether balance-enhancing shoes are preferable to minimalist shoes or participants’ own footwear, and whether function can be maintained while making the shoe more aesthetically pleasing |
| Footwear fit | Maden [62] and Hida [63] found balance performance increased when wearing appropriately fitting footwear compared to ill-fitting fitting footwear conditions. Hida [63] also found that ill-fitting footwear increases knee and ankle joint variability while walking in older adults which may be a risk factor for falls | Older people should wear shoes that fit appropriately, as ill-fitting shoes appear to pose an unnecessary balance hazard |
| Heel elevation | Lord [16] and Menant [18, 20] reported that footwear with an elevated heel (6 cm) impaired balance performance in older adults. Menant [19, 22] also found that older adults wearing higher heeled shoes employed a more conservative walking gait and also reported that pelvic acceleration in the mediolateral direction was reduced compared to other footwear conditions, suggesting a mechanical compensatory strategy to mitigate mediolateral instability from heel elevation. Menant [21] and de Mettelinge [66] reported footwear with elevated heels made no significant to walking stability performance. Lindemann [59] suggested that changes to heel height in different shoe conditions results in minimal differences if the heel elevation is below a critical value | Heel elevation in footwear can be detrimental to balance in older adults |
| Higher collar cut | Lord [17] and Menant [18, 20, 21] found higher collared footwear to be beneficial to balance in older adults. Menant [18, 21] also found higher collared footwear produced a significant reduction in total stopping time on wet surfaces and significant differences in toe clearance, double-support time and step width compared to the control condition. Two studies from Menant [19, 22] also reported that higher collared footwear did not change any temporo-spatial gait parameters during standing or walking compared to the control condition | Footwear with a higher collar may improve balance in older adults |
| Textured insoles | Qiu [23], Li [43], Huang [44], Perry, Maki [51], Kiaghadi [52], Asgari [54], de Morais Barbosa [64], and Palluel [69] all reported positive outcomes when older adult participants wore textured insoles compared to other conditions. Kiaghadi [52] concluded that older adults wearing textured insoles had a shorter reach length in three directions when completing the star excursion balance testa. Qu [39], Hatton [58], and Hartmann [70] however, found no difference in balance performance | While there appears to be some benefit in the addition of textured insoles, the optimum design and placement of the texture needs further study |
| Custom or contoured insoles | Mulford [33], Gross [34], Qu [39], Ma [42], Peng [45], and Kiaghadi [52] indicate that custom or contoured insoles are beneficial for balance when standing or walking. Kiaghadi [52] concluded that older adults wearing textured insoles had a shorter reach length in three directions when completing the star excursion balance testa | Custom or contoured insoles may improve balance in older adults |
| Vibrating insoles | Priplata [31], Galica [32], Stephen [35], Lipsitz [37], and Wang [40] found that insoles applying vibratory stimulation to the plantar surface of the foot in older adults increased balance performance | Vibrating insoles may improve balance performance in older adults, however, the issue of practicality of this intervention needs to be considered |
| Insole thickness or hardness | Qiu [23] and Iglesias [68] suggest that postural sway performance increased when wearing either hard or soft insoles compared to the barefoot condition. Buyukturan [61] reported that an insole with a thickness of 10 mm was optimal to improve static postural sway in older adults with a history of falls. Qu [39] found no evidence to suggest that either a soft or rigid insole improved balance performance in older adults, while Antontio [50] determined that changes to insole density did not significantly impact balance during stair-descent | Further research is required to understand which insole thickness and density is most beneficial to balance performance |
| Eversion insole | Nagano [27] found that insoles which promote dorsiflexion and eversion through the ankle joint can increase minimum foot clearance in older males, potentially reducing the risk of falls when compared to wearing no insoles | Due to limited research regarding eversion insoles, further research is required to determine the effect of this intervention on balance in older adults |
| Heel cups | Chen [41] reported that heel cups designed with an arch contouring device significantly improved standing balance performance in older adults. It is important to note, that this study did not have an active comparator and only assessed changes over time | Due to limited research involving heel cups, further research is required to determine the effect of this intervention on balance in older adults |
| Changes in midsole thickness or hardness | Menant [20] and Robbins [48] both noted that balance performance in older adults was improved when footwear incorporated a hard midsole (Shore A-58 and Shore A-50, respectively). Menant [18] reported footwear with a medium density midsole (Shore A-40) improved stability on various surfaces in older adults compared to the same shoe with various modifications (elevated heel, soft sole, hard sole, flared sole, bevelled heel, high collar, and tread outsole). Menant [18, 19, 21] and Robbins [48] found softer soles to be detrimental to balance performance compared to harder soled comparators. Menant [19] also reported minimal difference in balance performance between a medium density midsole shoe (Shore A-40), and a harder density midsole shoe (Shore A-58) over a range of surfaces. Lord [17] and Menant [22] saw no change in balance performance in older adults when changing the density of the midsole of footwear | A firm or hard midsole is beneficial for balance performance in older adults, while a softer density midsole may pose a risk for falls |
| Sole geometry or rocker soles | Takeshi [47] reported that increasing sole width of footwear improved lateral stability in older adults. Thies [56] found that by increasing the degree of the forefoot rocker, minimum toe clearance in older adult participants also increased. Menant [18, 20, 21] also found negligible differences in footwear that included either a flared or bevelled heel block compared to the control and other active comparator conditions | Further research is required to determine which modification to sole geometry is most effective |
| Outsole tread | Menant [18‒21] found that shoes with an outsole tread were neither beneficial nor detrimental to balance performance compared to the control conditions, suggesting that shoes with an outsole tread may be worthy of consideration as they do not seem to impair balance performance | Outsole tread did not impact balance, however it is likely to influence slipping in wet conditions [72‒74] and should therefore be a consideration in older adults |
| Minimalist footwear | Cudejko [55] reported that older adults with a history of falls had better performance in the Timed Up and Go and star excursion balance tests when in minimalist shoes compared to conventional footwear and barefoot condition, while Petersen [67] found minimalist shoes to increase local dynamic stability and reduce minimum toe clearance variability in older adults. However, Menz [26] found minimalist shoes to have no effects on temporo-spatial parameters in older women when compared to the control and comparator conditions | Minimalist footwear may improve balance performance on level surfaces in the short-term; however, for longer periods of time and on more challenging terrain, minimalist footwear may become uncomfortable for older adults |
| Slippers and socks | Hida [63] and de Mettelinge [66] found balance performance in older adults was not impacted by the use of slippers compared to other comparator conditions. However, Menz [25] found that slippers incorporating an enclosed heel and Velcro fixation enhanced balance performance in older women compared to slippers with an open-back heel. Pinvaninchkul [71] reported socks with a textured footbed was deemed to be beneficial for balance compared to a standard sock alone, while Ma [42] found postural sway performance was worse when older adults wore socks only, compared to barefoot and socks plus insole conditionsb | While slippers and socks are accessible options for older adults especially for indoor settings, older adults are more likely to fall indoors when wearing slippers or socks [75]. Therefore, it would be appropriate to advise older adults to wear shoes indoors |
| Unstable footwear | Sobhani [53] reported improved performance in the Fullarton Advanced Balance Scale, maximum and preferred gait speed in the unstable footwear condition compared to the stable footwear condition | Due to limited research involving unstable footwear, further research is required to determine the effect of this intervention on balance in older adults |
Discussion
The aim of this scoping review was to identify and synthesise the current evidence examining the effects of footwear, orthoses, or insoles on balance in older adults, with a view to identifying which features, in isolation or in combination, exert the most positive impact. We included 56 studies originating from 17 countries that reported the effects of 17 different interventions using 23 different outcome measures with follow-up varying from immediate to 6 months. Most studies originated from Australia, the USA, and China, examined immediate effects using a cross-sectional design, assessed the effects of textured insoles, heel elevation, non-standardised footwear, and changes in sole thickness or hardness, and used postural sway and/or temporo-spatial parameters as outcomes of interest.
The variability in study designs, and interventions evaluated across the included studies, made a synthesis of the evidence challenging. Overall, the findings from this review indicate that footwear with high collars, textured insoles, custom or contoured insoles, firm-to-hard density midsoles, and adequate fixation are all features which have been demonstrated to be beneficial, while elevated heels, poor fit or fixation and soft midsoles impair balance performance. However, it remains unclear whether the shoe features and orthotic and insole designs described above are most effective when used individually or in combination, as this was not specifically evaluated in any of the included studies. Further, as the majority of the studies included in this scoping review were cross-sectional or cohort studies, as opposed to randomised trials, there is uncertainty regarding the magnitude of effects observed from the interventions.
Implications
The findings from this review support clinicians in advocating for the continued use of well-fixed, firm-to-hard-soled footwear with a textured insole and high ankle collar for the older adult population to reduce the risk of falls. Conversely, the use of footwear with elevated heels, poor fit or fixation, and soft midsoles should be discouraged as it may increase the risk of falls. However, our findings suggest that further research is necessary to evaluate the comparative efficacy of footwear and orthotic/insole interventions, whether used individually or in combination, on balancing performance. Future research should employ randomised trial study designs as they represent the gold standard for evaluating intervention efficacy. These trials should be designed to allow adequate habituation of the intervention(s) to occur.
Limitations
The findings of this scoping review should be interpreted in the context of its limitations. First, we did not include publications that were published in a language other than English, so it is possible that there were additional studies not included in this review. Second, we limited our studies to older “healthy” adults, as we did not include studies that included participants with conditions known to affect balance (e.g., diabetes, Parkinson’s disease, stroke). Therefore, the findings are not generalisable to these populations.
Conclusions
There is a substantial body of literature exploring the effects of footwear, orthoses, and insoles on balance on older adults. However, considerable uncertainty exists regarding the efficacy of these interventions due to variability in methodological approaches. Certain features, such as a textured insole, a medium-to-hard density midsole, and a higher ankle collar, when used in isolation, demonstrate favourable effects on balance. Further high-quality research is necessary to determine whether a singular intervention or a combination of interventions is most effective for enhancing balance in older adults.
Conflict of Interest Statement
The authors have no conflicts of interest to declare.
Funding Sources
A.N.A. is supported by an industry scholarship co-funded by La Trobe University and ecnalabs Pty Ltd.
Author Contributions
Ameer Nor Azhar, Shan M. Bergin, Shannon E. Munteanu, and Hylton B. Menz contributed equally.
