Tag Archives: high heeled footwear

Does Wearing High-heeled Shoe Cause Hallux Valgus? A Survey of 1,056 Chinese Females

by Daniel Wu, MD1  , Lobo Louie, DPE2  

The Foot and Ankle Online Journal 3 (5): 3

Objective: To determine the prevalence of hallux valgus and its relationship to wearing high-heel shoes in Chinese females.
Methods: A total of 1,056 healthy females between the ages of 18 and 65 responded to the self-reported questionnaires. Photographs of each classified hallux valgus condition were given as references and each respondent was asked to rate her foot condition as well as completing a questionnaire. The study took place between June and August 2008 in Hong Kong.
Data analysis: Cross-tabulation and frequencies commands were used to compute the incidences of hallux valgus with regard to age, severity of illness, complaints and actions taken by the respondents. A chi-square statistic was used to compare the frequencies of occurrences between younger and older respondents. The relative risk (RR) was calculated in order to understand the probability of having hallux valgus in relation to wearing high-heels and family history.
Results: Of the 1,056 respondents, 36.5% indicated having various degree of hallux valgus. 29.5% (n=312) had ‘mild’ condition, 4.8% (n=50) had ‘moderate’ and only 2.2% (n=24) reported ‘severe’ hallux valgus. No ‘extreme’ case was reported. Subjects over aged 40 had higher injury prevalence (chi-square=34.4; p<.01) than the young counterparts. 88.8% of those having hallux valgus reported that their family members had history of hallux valgus. 73.2% of them who did not wear high-heels regularly but with family history also had hallux valgus. For those with no family history but often wore high-heels, only 2.8% had hallux valgus. Subjects with family history of hallux valgus would be 26 times (RR=26) as likely as those without family history and often wore high-heeled shoes to develop hallux valgus.
Conclusion: Hallux valgus is prevalent in the Chinese females. Wearing high-heels seemed to not be a predisposing factor of hallux valgus in Chinese females; however a family history was a major concern.

Key words: Hallux valgus, bunion, hallux abductovalgus, High-heeled shoe, Chinese females.

ISSN 1941-6806
doi: 10.3827/faoj.2010.0305.0003


Hallux valgus is a chronic condition with deformity of the first metatarsophalangeal joint. It is characterized by lateral drift of the great toe in association with joint subluxation. The occurrence rates for hallux valgus varied depending on the age of the subjects involved. [1]

It was reported that the frequency rates of hallux valgus in the adult wearing population were about 33%. [2] Another study indicated that the standardized prevalence of hallux valgus was 28.4% based upon a large sample of 4,249 respondents in a primary care population. [3] It was found that this deformity was associated with age, female sex, and components of generalized osteoarthritis, such as knee pain and big toe pain. However, hallux valgus was found as high as 64.7% in rural Korean women with age between 40 and 69, but it did not significantly correlate with age. [4]

In a study done by Coughlin and Jones, [5] they collected data from patients treated for a hallux valgus deformity and found that 83% of patients had a positive family history for hallux valgus deformities. Constricting shoes and occupation were implicated by 34% patients as a cause.

A recent study found that the prevalence of hallux valgus was associated with body mass index and high-heel use during ages between 20 and 64. [6] They also reported that women, who wore regularly high-heeled shoes increased likelihood of hallux valgus. It is widely believed that dancers may put a great deal of stress through the first metatarsophalangeal joint which caused hallux valgus, but research did not support this assumption. [7,8]

Although the literature pertaining to the etiology of hallux valgus tends to be varied, there would appear predominantly on female population. The purpose of this study was to focus on evaluating the prevalence of hallux valgus and its relationship to wearing high- heeled shoes in Chinese females.

Methods

A user-friendly self-report instrument containing photos of different degrees of hallux valgus were utilized (Fig. 1). Such classifications obtained high reliability and validity and this non-invasive method of assessing the severity of hallux valgus deformity was suggested for clinical and research purposes. [9,10] In addition, data collected also included demographic information, wearing high-heeled shoes habit, family history, pain and symptoms, influence on daily life, diagnosis and treatment. Convenience sample method was used but the age of the respondents must be between 18 and 65 years. Questionnaires were delivered to the potential respondents in the community centers located in various districts in Hong Kong. In order to minimize the sample selection bias, the researcher distributed the questionnaires to the potential respondents in a random order. The researcher did not know whether the respondents had hallux valgus or not prior to distributing the questionnaires. Each respondent was asked to rate her own foot condition according to the given photos as well as filling out a questionnaire. The study took place between June and August 2008 in Hong Kong. Ethical approval was obtained.

Figure 1 Self-rated hallux valgus conditions by the respondents. Characterized as normal foot (A), mild bunion (B), moderate bunion (C), severe bunion (D) and extreme bunion (E).

Data Analysis

Data were analyzed utilizing the Statistical Package for Social Sciences (SPSS version 16.0). Cross-tabulation technique was used to compute the incidences of hallux valgus between younger and older age groups, and across various severity of illness. In addition, frequencies command was employed to compute the descriptive statistics for the complaints and related actions taken by the respondents with hallux valgus. A chi-square statistic was utilized to compare the frequencies of occurrences between the younger (age 18-40 years) and older (age 41-65 years) groups. In an attempt to understand the probability of having hallux valgus in relation to family history and wearing high-heels, the relative risk (RR) was calculated by dividing the number of hallux valgus cases who did not wear high-heels but with family history by those wore high-heels with no family history. In order to facilitate data interpretation, percentage scores were utilized. Significance level was less than 0.05.

Results

In total, 1,080 Chinese females responded to the survey. Twenty-four data entries were dropped due to incomplete information and thus 1,056 usable data were input for analysis (a return rate of 98.0%). The demographic characteristics of the respondents indicated that they were from different socio-economic backgrounds, including clerical workers (29.7%), salespersons (4.4%), flight attendants (6.2%), service workers (4.5%), teachers (12%), discipline force (6.8%), health care (6.4%), and housewives (30.1%).

Of the 1056 respondents, 36.5% indicated having various degree of hallux valgus. It was reported that 29.5% (n=312) had a ‘mild’ condition, 4.8% (n=50) had ‘moderate’ and only 2.2% (n=24) noted ‘severe’ hallux valgus. The findings also noted that 34.3% and 41.4% of the subjects with aged 18 – 40 and 41 – 65 years had hallux valgus, respectively. (Table 1) Respondents over aged 40 had significantly (chi-square = 34.4; p < 0.01) higher injury prevalence than their young counterparts.

Table 1 Age difference in the prevalence of hallux valgus.

Of the total respondents, 226 (21.4%) indicated that they always wore high-heeled shoes and 453 (42.9%) sometimes wore them. The average year of wearing high-heels was 9.4 years (minimum =0.5 years; maximum =38 years). Similar average year (10.0 years) of wearing high-heels was also found in the hallux valgus group. Table 2 showed the frequent complaints reported by the respondents with hallux valgus. Some actions taken by the respondents with hallux valgus were presented in Table 3.

Table 2 Frequent Complaints by the respondents with hallux valgus.

Table 3 Actions taken by the respondents with hallux valgus.

Eighty eight percent of respondents who had hallux valgus reported that their family members also had some forms of hallux valgus. However, it was found that 73.2% of them did not wear high-heels regularly but all had family history of hallux valgus. On the other hand, for those respondents without family history but often wore high heels, hallux valgus was found only in 2.8% of the total cases. It was estimated that subjects with family history of hallux valgus would be 26 times (rr = 26) as likely as those without family history and often wore high-heeled shoes to develop hallux valgus. A summary showing the prevalence of hallux valgus between high- heels and family history was shown in Table 4.

Table 4  A summary showing the prevalence of hallux valgus between wearing high-heels and family history.

Discussion

Occurrence rates for hallux valgus reported in the literatures varied from 33% and 70%.2,11,12 The present finding (36.5%) on the prevalence of hallux valgus in Chinese females was in line with previous data from other populations. [4,6]

Some people blame the causes of hallux valgus may be due to high heels. Wearing high-heels can be fashionable. Some people believe that high-heels can empower women at work and help women look and feel confident. Although wearing high-heels can cause several deleterious effects, such as putting too much force on the feet, ankles, knees, and lumbar, [13,14,15] high-heels are welcome by women around the world. While wearing high-heels the feet are in plantarflexed position, which in turn significantly increases pressure on the plantar of the forefoot.

The pressure increases as the height of the shoe heel increases. Wearing a 3 1/4 inch heel increases the pressure on the bottom of the forefoot by 76%. The increased pressure may lead to pain or foot deformities.

Conversely, previous literature reviewed that constricting footwear was only found in about one-quarter of the hallux valgus patients. [16] In the present study, for those with no family history but often wore high-heels, only 2.8% of them developed hallux valgus. Apparently, the present finding did not agree with the cause of hallux valgus was due to wearing high-heels. Yet there is still insufficient evidence to conclude that wearing high-heeled shoe is an etiological factor in the development of hallux valgus. [17]

Almost 90% of respondents who had hallux valgus indicating that their family members also had some forms of hallux valgus. Such prevalence of hallux valgus was in line with the study conducted by Coughlin and Jones, [5] 83% of hallux valgus patients had a positive family history. Recent study also showed that 90% of hallux valgus patients had at least one family member affected by the presence of hallux valgus and it might affect some family members across three generations. [18] Interestingly, the present survey reported that a majority of the hallux valgus respondents (73.2%) had family history of hallux valgus but they did not wear high-heels. This is exactly in line with Coughlin and Jones [5] who reported that a positive family history is the underlying factor for hallux valgus deformities.

Conclusion

Hallux valgus is considered by many to be a prevalent condition in the females. This present study found that wearing high-heels is not a predisposing factor to hallux valgus. Instead, a family history appeared to be a major concern for developing hallux valgus in Chinese females.

Disclosure

No conflict of interest is reported by the authors.

References

1. Gilheany MF, Landorf KB, Robinson P. Hallux valgus and hallux rigidus: A comparison of impact on health-related quality of life in patients presenting to foot surgeons in Australia. J Foot Ankle Res 2008 1: 14.
2. Mann RR, Coughlin MJ. Adult hallux valgus. St Louis: Mosby 1993.
3. Roddy E, Zhang W, Doherty M. Prevalence and associations of hallux valgus in a primary care population. Arthritis Rheum 2008 59(6): 857-862.
4. Cho NH, Kim S, Kwon DJ, Kim HA. The prevalence of hallux valgus and its association with foot pain and function in a rural Korean community. JBJS 2009 91B (4): 494-498.
5. Coughlin MJ, Jones CP. Hallux valgus: demographics, etiology, and radiographic assessment. Foot Ankle Int 2007 28(7): 759-777.
6. Nguyen US, Hillstrom HJ, Li W, Dufour AB, Kiel DP, Procter-Gray E, Gagnon MM, Hannan MT. Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston study. Osteoarthritis Cartilage 2010 18(1): 41-46.
7. Kennedy JG, Collumbier JA. Bunions in dancers. Clin Sports Med. 2008 27(2): 321-328.
8. Einarsdóttir H, Troell S, Wykman A. Hallux valgus in ballet dancers: a myth? Foot Ankle Int. 1995 16(2): 92-94.
9. Roddy E, Zhang W, Doherty M. Validation of a self-report instrument for assessment of hallux valgus. Osteoarthritis and Cartilage 2007 15: 1008-1012.
10. Garrow AP, Papageorgiou A, Silman AJ, Thomas E, Jayson MI, Macfarlane GJ. The grading of hallux valgus: the Manchester scale. JAPMA 2001 91(2): 74-78.
11. Dawson J, Thorogood M, Marks SA, Juszczak E, Dodd C, Lavis G, Fitzpatrick R. The prevalence of foot problems in older women: a cause for concern. J Public Health Med 2002 24(2): 77-84.
12. Menz HB, Lord SR. Gait instability in older people with hallux valgus. Foot Ankle Int 2005 26(6): 483-489.
13. Lee CM, Jeong EH, Freivalds A. Biomechanical effects of wearing high-heeled shoes. Int J Ind Ergo 2001 28: 321-326.
14. Mandato MG, Nester E. The effects of increasing heel height on forefoot peak pressure. JAPMA 1999 89(2): 75-80.
15. Kerrigan DC, Todd MK, Riley PO. Knee osteoarthritis and high-heeled shoes. Lancet 1998 351(9113): 1399-401.
16. Coughlin MJ. Juvenile hallux valgus: etiology and treatment. Foot Ankle Int 1995 16(11): 682-697.
17. Easley ME, Trnka HJ. Current concepts review: Hallux valgus part 1: pathomechanics, clinical assessment, and nonoperative management. Foot Ankle Int 2007 28(5): 654-659.
18. Piqué-Vidal C, Solé MT, Antich J. Hallux valgus inheritance: pedigree research in 350 patients with bunion deformity. J Foot Ankle Surg 2007 46(3): 149-154.


Address correspondence to: Stephen Hui Research Centre for Physical Recreation & Wellness, Hong Kong Baptist University, Kowloon, Hong Kong. (852)3411-5631 Email: s62591@hkbu.edu.hk

Department of Orthopaedics and Sports Injury, Hong Kong Adventist Hospital, Hong Kong. (852)2525-5035.
Stephen Hui Research Centre for Physical Recreation & Wellness, Hong Kong Baptist University, Kowloon, Hong Kong. (852)3411-5631.

© The Foot and Ankle Online Journal, 2010

Influence of High Heeled Footwear and Pre-fabricated Foot Orthoses on Energy Efficiency in Ambulation

by Sarah A. Curran PhD, BSc(Hons)1 , Joanna L. Holliday BSc(Hons)1, Laura Watkeys BSc(Hons)2

The Foot and Ankle Online Journal 3 (3): 1

Background: Although changes in kinematics and repetitive impact forces produced by high heeled footwear can be minimized by pre-fabricated foot orthoses, their effects on energy efficiency and comfort are less understood. The purpose of this study was to investigate if an increase in high heeled footwear and selected pre-fabricated foot orthoses altered energy consumption and improved comfort.
Materials and Method: Ten healthy females (age range 21 – 34 years) who were regular high heel wearers volunteered for the study. Five footwear conditions were randomly assigned: heel height of 15mm (flat), 45mm (low), 70mm (high), high with McConnell® orthosis and high with Insolia® orthosis. Heart rate (HR), volume of oxygen consumed in liters per kilogram (VO2/kg), respiration exchange ratio (RER), physiological cost index (PCI) and the number of steps (NoS) were monitored whilst walking on a treadmill at a speed of 4.2km/hour and 0% incline for 10 minutes. The Footwear Comfort Scale was also completed following each condition.
Results: HR, VO2/kg, RER, PCI and NoS were significantly increased for the high (p<0.001) condition compared to the flat and low conditions. Significant differences (p<0.001) were also noted between the high and high with McConnell® and Insolia® conditions with a reduced HR, VO2/kg, RER, NoS and PCI. A significantly improved overall Footwear Comfort Scale was also noted between the high, McConnell® and Insolia® conditions (p<0.001).
Conclusions: This study supports previous work that wearing high heels are less energy efficient than flat shoes. It also suggests that selected pre-fabricated foot orthoses in high heeled footwear may improve energy efficiency and perceived comfort to wearing high heels alone. These combined benefits and the specific design of biomechanical interventions of orthoses for high heeled footwear should be explored further.

Key words: High heeled footwear, Energy, Physiological cost index, Pre-fabricated orthosis, Comfort.

Accepted: February, 2010
Published: March, 2010

ISSN 1941-6806
doi: 10.3827/faoj.2010.0303.0001


Modern day fashion trends continue to promote the design and popularity of high heeled footwear. Surveys have shown that up to 59%of American women [1] and 78% of British women [2] wear high heels on a daily basis.

The reasons for wearing this style of footwear vary greatly with many women stating that they feel more confident and glamorous from the extra height gained. [1,3] A further attraction relates to the appearance of a shorter foot, which is achieved by increasing arch height. [4,5] This is also supported by Frey et, al., [6] who found that 86% of American women wore high heeled footwear that was too small for their feet.

Whilst elegance is perceived as a key characteristic, by its very nature the design of high heeled footwear can be considered as having a profound impact on gait and posture, and in particular lower limb function.

Efficient walking is achieved by forward transmission of one limb to the next using the least amount of energy. [7] Footwear with a low heel is thought to conserve energy by providing a normal heel strike and smooth forward transmission of the limb. In contrast, high heeled footwear can result in an early heel strike and increased rearfoot inversion. [8-11] Other alterations are a plantarflexed ankle throughout stance, which produces postural changes causing the hip and knee to flex. [9,12-14] The plantarflexed foot position increases loading to the forefoot and in particular the first and second metatarsal heads. [8,15-21] During swing phase, hip flexion is thought to be reduced, and whilst cadence may not be affected by high heels, stride length and velocity are decreased. [12] Muscle function is also altered during high heeled walking [8,22-26] with constant contraction of the lateral head of the gastrocnemius25 and an increase in activity of tibialis anterior [23,26] and rectus femoris. [26]

As a consequence to these changes, high heeled footwear is frequently linked as a cause or aggravating factor of pain and symptoms in the lower back, hip, knee, ankle and foot. [15,27,28] In particular, evidence suggests that individuals who wear a high heel take a longer period of time to reach maximum knee flexion which disrupting the screw home mechanism of the knee and thus predisposes the joint to injury. Moreover, Stefenyshyn, et al., [29] showed that compared to barefoot, high heeled footwear increased concentric knee extensor activity. These findings are also supported by Kerrigan, et al., [30-32] who found that high heels increase peak varus torque by up to 26% when compared to barefoot. As a result, these factors are thought to produce abnormal forces at the tibiofemoral and patellofemoral joint which in turn predisposes the knee to injury and degeneration.

Foot orthoses are considered to be beneficial in reducing the repetitive impacts and changes in kinematics produced by high heeled footwear. In particular, they aim to improve weight distribution, comfort and stability. A previous study by Yung-Hui and Wei-Hsien [15] showed that custom made foot orthoses can reduce impact forces; heel and medial forefoot pressures, and improve perceived comfort compared to no insert. In particular, the total contact insole (TCI) showed the largest reduction in impact force (33.2%) and medial forefoot pressure (24%), and the highest perceived comfort compared to no insert. This study addressed kinetics and comfort of custom made orthoses. The contributions of alterations to energy consumption and perceived comfort to an increased heel height have not been investigated using pre-fabricated foot orthoses.

Whilst it is clear that a number of studies have explored the effects of high heeled footwear on lower limb function and loading, only a few have reported their effects on energy consumption. Mathews and Wooten [33] noted an increase in energy expenditure in 10 females who walked on a treadmill wearing high heeled footwear. Ebbeling, et al., [28] also showed an increase in expenditure in heel heights of 50.8mm and above.

Energy consumption or expenditure is commonly recorded by directly measuring the volume of oxygen an individual has consumed. This approach however, is frequently restricted to a laboratory setting and has led to the introduction of proxy measures such as the ‘physiological cost index’. (PCI) [34] This simple measure determines walking efficiency [35] which has proven to be valid and reliable in a variety of health disciplines. [36] It is also able to discriminate between various treatment interventions and walking devices. [37-39] Nonetheless, to date the ability of the PCI to respond to changes in heel height is currently unknown and therefore requires investigation.

Investigating the impact of high heeled footwear and the effects of foot orthoses on energy consumption and comfort can provide the basis for improving the design of an orthosis and how to minimize pain and discomfort. The aim of this study was to examine if an increase in high heeled footwear and selected pre-fabricated foot orthoses changed energy consumption and improved perceived comfort. A secondary aim was to determine if the PCI, a proxy measure of energy consumption could be used as an indicator for monitoring the amount of energy used when wearing high heeled footwear.

Methods

Participants and materials

Ten female university students volunteered to take part in the study. The participants had a mean age of 26.3 years (standard deviation [SD] 5.4, range 21 – 34 years), mean weight of 61.4kg (SD 7.9, range 51 – 73.9kg), and mean height of 160.5cm (SD 4.4, 153 – 167cm). All participants met the following inclusion criteria: no cardiovascular or neuromusculoskeletal conditions that might influence their walking pattern; currently wear footwear (size 5 [38] – 6 [39]) with a heel 2 – 5 times a week for at least 1 year. Ethical approval was sought from the School of Health Sciences Ethics Committee, University of Wales Institute, Cardiff before the study began. The study’s purpose and procedures was fully explained to each participant. Informed consent was obtained from all participants before taking part.

The footwear used in this study was commercially available (Clarks© Ltd, UK) and were selected based on the similarity of construction such as forefoot width (D fitting) with a strap style and foot contact points. The key difference among this footwear was the height of the heel: a flat (15mm), a low (45mm) and a high heel (70mm) (Fig. 1 A – C). The foot orthoses used were commercially available pre-fabricated products: Insolia® (Insolia®, Salem, New Hampshire, USA) (Fig. 2 A and C) and Vasyli McConnell® Extended slim fit (Vasyli® International, Australia) (Fig. 2 B, D – E). To prevent slippage within the shoe, a new piece of double sided adhesive tape was applied to each prefabricated insert before each trial. Each participant was randomly assigned five conditions: (1) flat only (15mm); (2) medium only (45mm); (3) high only (70mm); (4) McConnell® (with high, 70mm); (5) Insolia® (with high, 70mm).

  

Figure 1 Footwear used for study (Clarkes© Ltd, UK).  (A = high, B = medium, C = flat)

Figure 2 Pre-fabricated orthotic inserts. A) and C) Insolia®  – the medial and lateral aspect of the insert are symmetrical.  B), D) and E) McConnell® – an increased in height of medial aspect of the insert is noted (D) compared to the lateral (E).

Equipment

A Woodway (Desmo, Germany) treadmill was used for each of the 5 experimental conditions. Volume of oxygen consumed in litres per kilogram (VO2/kg) and respiration exchange ratio (RER) were collected and calculated at one minute intervals using a Metalyzer 3B-R2 (Cortex, Germany).

The RER is the carbon dioxide (CO2) divided with O2 consumption. Heart rate (HR) was monitored using a VFIT monitor (Polarexpress Ltd, London), which was attached to the participant’s chest by a strap. This telemetry system records the electrical signals generated from the heart by the transmitter worn on the chest and displayed on a wristwatch receiver. A pedometer was used to record the number of steps (NoS) taken (WSG™ Digital Pedometer). The sensitivity of the pedometer was determined using the ‘shake test’ as described by Vincent and Sidman40 before data collection began. The pedometer was found to be within 3% of the actual number of shakes. The pedometer was positioned according to manufacturer’s instructions, and before data began the step number was cleared.

Footwear Comfort Scale

Following each walking trial the Footwear Comfort Scale [41] was used to determine the perceived comfort for the 5 conditions. The scale has been used by a number of authors [15,42] and consists of 8 questions (i.e. overall comfort, forefoot cushioning). Perceived comfort is rated using a 15mm visual analogue scale (VAS), with 0 (= 0 comfort point) labeled as ‘not comfortable at all’ and 15 as ‘the most comfortable condition imaginable’ (= 15 comfort points). For consistency, each participant was advised not to take into account the style and cosmetics of the footwear during comfort rating.

Procedures

Data was collected in a quiet physiology laboratory over 2 sessions, at the same time of day for approximately 1 hour. Prior to testing, the order for each experimental condition was randomly assigned to the participant to eliminate order effects. Before data collection began, each participant was given a 5 minute acclimatization period on the treadmill for each experimental condition. The speed of walking was standardized to 4.2km/hour at a 0% incline. This speed was chosen because it falls within the mean comfortable speed. [8,11,15,43]

Following acclimatization, data were collected over a further 5 minutes at the same standardized speed. To minimize fatigue, each participant was allowed a 20 minute rest between each experimental condition and/or until their HR returned to its resting value. Each participant was instructed to look straight ahead whilst walking on the treadmill. The procedure was terminated if the participant felt uncomfortable, showed an unsteady gait, signaled to stop or when the walking period was completed.

Data and statistical analysis

The mean, SD and range were calculated for all of the measures investigated. The PCI was calculated using the following equation: Walking heart rate – resting heart rate divided by speed (m/min). [34] A series of Kolmogorov-Smirnov tests were performed and showed all data to have a normal distribution p<0.001. A one-way analysis of variance (ANOVA) was performed to investigate the differences between each of the five conditions, whilst Tukey’s post hoc analysis was used to identify where the differences occurred. All data were analyzed using the software package SPSS® (version 15.0, London, UK) and a significance level set a p<0.05.

Results

Differences: Metabolic variables and efficiency

The mean, SD and range for HR, VO2/kg, RER, NoS and PCI for each of the experimental condition are summarized in table 1. The one-way ANOVA showed significant differences between the five conditions for HR (F = 3.522, df 4, p=0.014). RER (F = 14.418, df 4, p<0.001); VO2/kg (F = 7.391, df 4, p<0.001); NoS (F = 14.190, df 4, p<0.001), and PCI (F = 12.532, df 4, p<0.001).

Table 1 Mean, SD and range of each condition and variable measured (*significant differences p<0.001, one-way ANOVA).

Tukey’s post hoc analysis for HR only revealed significant differences (p<0.001) between flat and high condition, with a 23.5% increase in HR noted for the high condition. Post hoc analysis for VO2/kg demonstrated a series of significance differences (p<0.001) between the flat and medium, flat and high conditions. An increase in VO2/kg of 22.4% was noted for the high condition and slightly lower value of 15.5% observed for the medium condition.

Further differences were demonstrated between the high and McConnell® and Insolia® conditions. The VO2/kg was reduced by 22.2% for the McConnell® and 26.5% for the Insolia® condition.

Tukey’s post hoc comparisons revealed differences between the flat and high condition for the RER with a 25% (0.21) increase noted for the high condition. Significance differences were also noted between the high, the McConnell® and Insolia® conditions. The RER was noted to be reduced by 18% (0.15) and 25% respectively (0.21) compared to the high condition.

Post hoc analysis for the PCI revealed significant differences between the flat and medium, and flat and high conditions. A lower PCI of 58% (0.237) and 72% for the flat condition was noted when compared to the medium and high conditions respectively. Tukey’s analysis also demonstrated significant differences between the high and McConnell® and Insolia® conditions (p<0.001). The PCI was reduced by 49% and 41% for the McConnell® and Insolia® condition when compared to the high heel conditions.

Post hoc analysis demonstrated significant differences for NoS between all three height conditions (i.e. flat, medium and high) with more steps taken for the medium (13.6%) and high (17.8%) conditions.

Post hoc analysis also showed significant differences between the high and McConnell®, and high and Insolia® conditions. Fewer steps were taken with McConnell® (10.8%) and Insolia® (13.7%) conditions.

Differences: Footwear Comfort Scale

The one-way ANOVA indicated significant differences between the five conditions for overall comfort (F = 4.213, df 4, p=0.06), heel cushioning (F = 5.108, df 4, p=0.002), forefoot cushioning (F = 5.571, df 4, p<0.001) and heel cup fit (F= 8.308, df 4, p<0.001). No significant differences were noted between the five conditions for the medio-lateral control (F = 8.470, df 4, p=0.269), arch height (F = 1.387, df 4, p= 0.254); shoe heel width 7.802, df 4, p=0.063), and shoe length (F = .783, df 4, p=0.542). Fig. 3 illustrates the comparison of perceived ratings for the five conditions.

Figure 3  Eight questions of the Footwear Comfort Scale and the 15mm VAS line.

Compared to the high condition (mean 7.8, SD 2.8) tukey’s post hoc analysis showed a significantly higher overall comfort rating for the McConnell® (mean 11.8, SD 1.6) and Insolia® conditions (mean 11.1, SD 1.4), with a 34% and 30% increase respectively. Post hoc analysis using Tukey’s revealed significant differences between the high and McConnell® (p=0.018) and the medium and McConnell® (p=0.002) conditions for heel cushioning. The mean rating of 12.9 (SD 1.5) was noted for the McConnell® condition, and was increased by 29% (mean 9.2, SD 2.7) and 35% (mean 8.4, SD 3.9) compared to the high and medium conditions.

Post hoc analysis demonstrated significant difference between the flat and high condition (p=0.017) for forefoot cushioning. It was noted that the flat condition had a mean rating of 9.2 (SD 2.8), whilst the high condition had a reduced rating of 6 (SD 1.2) producing a mean difference of 35%.

Further significant differences were noted between the high and McConnell® (p=0.034) and Insolia® (p<0.001) conditions for forefoot cushioning. The McConnell® condition had a higher mean rating of 9.4 (SD 1.5), whilst a rating of 11 (SD 1.2) was noted for the Insolia® condition. Compared to the high condition, this produced a mean difference of 36.5% and 46% for the McConnell® and Insolia® condition respectively.

Post hoc analysis also showed significant differences for heel cup fit between the flat and medium (p<0.001); flat and high (p<0.001); medium and McConnell® (p=0.035); and high and McConnell® (p=0.022) conditions. The flat condition had a higher mean rating of 11.4 (SD 2.5) compared to the medium and high conditions which had ratings of 6.2 (SD 2.9) and 6 (1.2) respectively. This produced a mean difference of 46% for the medium and 47% for the high condition. The McConnell condition had a mean heel cup fit rating of 9.6 (SD 2.2), which was 35.5% and 38% higher compared to the medium and high conditions. Figure 4 illustrates the mean values for each sub-section of the Footwear Comfort Scale and the significant differences between conditions.

Figure 4 Footwear Comfort Scale results for all five conditions. (  ———   = p<0.05 significant differences between conditions) (McCon® = McConnell®; Insol® = Insolia®)

Discussion

This study sought to establish the influence of high heeled footwear and pre-fabricated foot orthoses on gait efficiency and perceived comfort. A further aim investigated if a proxy measure, the PCI could be used as an indicator for assessing energy expenditure whilst wearing high heeled footwear. The results of this study demonstrated clear links between an increase in energy and a reduction in perceived comfort as heel height increased. This link was reduced (reversed) upon the implementation of 2 types of pre-fabricated foot orthoses (McConnell® and Insolia®) which showed an improved efficiency and perceived comfort.

In this study, energy efficiency was derived from a series of measures which included HR, RER, VO2/kg and PCI. Although HR only showed a significantly higher increase of 23.5% for the high condition compared to the low, this finding is consistent with previous studies.28,43 Significant differences were noted between all five conditions for RER, VO2/kg and PCI. It was noted that the largest increase occurred between the flat and high conditions for the RER and VO2/kg, which again supports previous literature. [28]

The data for the RER was at its highest (0.85) for the high condition which suggests that both fat and carbohydrates were the fuel source. Whilst the RER for the medium condition was at 0.79 (approaching a mixed source fuel), it was noted that that the use of the McConnell® and Insolia® orthoses significantly reduced the RER to 0.70 and 0.64. This may indicate that the amount of energy (i.e. fat) used was reduced thus increasing overall efficiency. However, it could be argued that the RER results presented here seem a little high, which could be attributed to a small sample size. Therefore, further research involving a longer period of walking would be useful to gain a clearer picture of this parameter in high heel walking.

The PCI showed similar trends, but most notable were the significant differences observed between the high and McConnell® and Insolia® conditions. Here the values for the PCI were reduced to 49% (McConnell®) and 41% (Insolia®) and whilst these values were not as low as flat condition, the results do suggest that the use of pre-fabricated foot orthoses can reduce the amount of energy consumed. Since no previous data exists for the PCI in relation to high heeled footwear and pre-fabricated foot orthoses, direct comparisons are limited.

It is known that at a set speed, the most economical stride length and NoS are chosen. For this study, a pedometer was used to measure the naturalistic activity of the NoS for each condition whilst walking at a standardized speed of 4.2km/hour.

There was an increase in the NoS taken during the medium (13.6%) and high (17.8%) conditions compared to the flat condition. The increased use of energy whilst walking in high heels can be explained by the changes in lower limb biomechanics and stride pattern. An increase in heel height is considered to plantarflex the foot, and flexes the hip and knee. These angular changes therefore result in a shorter stride length. [8,9,12,15,19,28,44] Since the speed was kept constant throughout all of the conditions, the NoS during the high condition had to increase, which in turn, used more energy. Comparisons between the high and orthoses condition also showed significant differences with fewer NoS taken for the McConnell® (10.8%) and Insolia® (13.7%) conditions. Taking larger and fewer steps however may be a negative factor since less steps may result in higher sagittal and varus knee torques30-32 which in turn leads to joint damage (i.e. degenerative changes of the tibiofemoral and patellofemoral joints). Moreover, longer activation times of the rectus femoris16 and co-contraction of other lower limb muscles may also be linked to longer stride patterns which warrants further exploration.

While the findings presented in this study cannot suggest a dramatic angular change within the lower limb, it could be assumed that the pre-fabricated orthoses discreetly altered lower limb function. This assumption relates to a new paradigm advocated by Nigg which suggests that orthoses can filter the impact forces placed upon the foot and adjust muscular response to allow the individual to sustain their ‘preferred movement pathway.’ [45] Although it can be stated that wearing high heels will always influence lower limb function, adaptability to the condition and cushioning via foot orthoses are likely to have contributed to these changes. Moreover, all participants who took part in this study were experienced heel wearers and are likely to have already undergone soft tissue adaptation in the form of Davis’s law. [46]

Whilst kinetic analysis was beyond the scope of this present study, it could be assumed that the elastic (pressure) and viscosity (impact force) properties of the orthosis material could provide a number of benefits. For example, as well as providing cushioning they may have enhanced the capability of energy absorption and potential kinetic energy the lower limb body already processed. This may be particularly relevant for the McConnell® orthosis during heel impact, since it appeared to provide more cushioning. The Insolia® product however, is devised on the principle that weight is shifted posterior to the rearfoot, minimizing pressure and force within the forefoot. By controlling this pathway of progression during walking it could be suggested that less energy is used and stored, thus creating improved efficiency whilst walking in high heels.

Perceived comfort was influenced by heel height and the use of the orthoses (McConnell® and Insolia®). Four out of the eight sections of the Footwear Comfort Scale (overall comfort, heel cushioning, forefoot cushioning and heel cup fit) were significantly different between the five conditions. The mean overall comfort rating was 11 for the flat condition but reduced to 7.8 for the high heel condition. This value however, improved with the use of the McConnell® (mean 11.8) and Insolia® (mean 11.0) orthoses. These findings support previous work 3,15 and suggest that higher heels are uncomfortable, but the use of pre-fabricated foot orthoses can provide an improved comfort which is similar to that of flat footwear. Whilst the McConnell® and Insolia® conditions showed significantly improved ratings compared to the high condition (mean 9.2) for heel cushioning, it was noted that the McConnell® orthosis had a higher comfort score. This however, was not significant, but may indicate better shock absorbing properties of the McConnell® orthosis.

As with previous subsections of the footwear scale, the mean forefoot comfort score for the flat foot was higher at 9.2 and reduced to 6 for the high condition.

This was the lowest comfort score out of the 8 conditions; however the use of pre-fabricated foot orthoses significantly improved comfort with a mean of 11.7 noted for the McConnell® and 12.9 for the Insolia® orthosis. The lower value noted for the McConnell® orthosis can be attributed to impingement under the first metatarsal head that was stated by 7 out of the 10 participants. Furthermore, the improved comfort experienced during the Insolia® condition could be due to the reduced pressures at the forefoot as the orthosis shifts the weight from the forefoot to the midfoot and rearfoot.

A number of limitations are acknowledged in this study. Firstly, the study may have been limited to the immediate effects of orthoses and the various heel heights on gait efficiency and perceived comfort. Secondly the sample size was small and did not include a wide age range. Thirdly, data collection was limited to a laboratory setting and required participants to walk at a standardized speed in a straight line over a short period of time.

This approach can be considered as unrealistic since it fails to capture the everyday setting such as the required multi-directional changes in walking pattern and fatigue often experienced by women at the end of a day. In spite of these limitations, the inclusion of the PCI in this study has shown that it responds to an increase in heel height. The measure is appealing, since it is a simple and cost effective tool that can be used outside of the laboratory. Future research should focus on a larger and more diverse sample population that should include data collection at the beginning and end of the day to establish the role of fatigue. Multi-directional walking patterns such as the ‘figure of 8’ method36 could also be used. Information gained from additional studies can help to document the effects of high heeled footwear and to optimize the design and selection of pre-fabricated orthoses.

Clinical significance

The findings of this study should be viewed in terms of clinical context and significance. The wearing of high heeled footwear is discouraged by health care professionals with an interest in lower limb function and care. However, products such as the McConnell® and Insolia® (as well as others) have been produced in an attempt aid comfort and reduce the damaging impacts associated with wearing high heels. Whilst this study suggests some benefits of pre-fabricated foot orthoses when wearing high heels, further research is required. This should involve kinetic, kinematic and electromyography to determine the effects of these pre-fabricated orthoses over a set period of time (i.e. to establish fatigue patterns).

Conclusion

The present results provide further information of the influence of high heeled footwear on energy efficiency and perceived comfort. The use of 2 pre- fabricated orthoses; the McConnell® and Insolia® have been shown to reduce the amount of energy used, as well as improve comfort whilst wearing footwear with a 75mm heel. The PCI represents a useful measure for documenting walking efficiency in high heeled footwear. Future research should be undertaken to determine how well the results generalize to more realistic walking patterns (multi-directional) and longer periods of wear to establish fatigue.

Acknowledgements

The authors would like to thank Mr Bob Hardy (Clarks, UK) for providing the footwear used in the study. We would also like to thank Mr Steve Sheldon (Canonbury Healthcare, UK) for supplying the pre-fabricated orthoses.

Conflicts of Interest

There are no conflicts of interest.

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16. Hwang YT, Pascoe DD, Kim CK, Xu D. Force patterns of heel strike and toe off on different heel heights in normal walking. Foot Ankle Int 2001 22 (6): 486-492.

Volume 3, No. 3, March 2010 Curran, Holliday, Watkeys________________________________________

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Address correspondence to: Sarah A. Curran PhD, BSc(Hons)
Senior Lecturer, Wales Centre for Podiatric Studies, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK. Email: scurran@uwic.ac.uk; Phone +44 (0) 29 2041 7221.

1   Wales Centre for Podiatric Studies, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK..
2  Centre for Biomedical Sciences, University of Wales Institute, Cardiff, Western Avenue, Cardiff, CF5 2YB, UK.

© The Foot and Ankle Online Journal, 2010