Background: The purposes of this study were 1) to determine the intrarater and interrater reliability of the arch height index measurement system device, 2) to establish population normative values for the arch height index in recreational runners, and 3) to compare arch height index values between the right and left feet and between genders.
Methods: Eleven subjects were used to establish intrarater and interrater reliability of the arch height index measurement system. This system was then used to measure the arch height index of 100 recreational runners.
Results: Measurements taken with the arch height index measurement system device exhibited high intrarater and interrater reliability. The mean ± SD arch height index of the recreational runners was 0.340 ± 0.030. Men had larger feet than women, but the arch height index between genders was similar.
Conclusions: The arch height index measurement system device is reliable to use between testers while simplifying the measurement procedure for recording the arch height index. The arch height index may be helpful in identifying potential structural factors that predispose individuals to lower-extremity injuries. (J Am Podiatr Med Assoc 98(2): 102–106, 2008)
The arch height index measurement system (AHIMS) device has been found to be a reliable and valid instrument for measuring the arch height index (AHI) of the feet of individuals; however, normative data for the AHI are lacking for various populations. Therefore, the purposes of this study were to establish population normative AHI values for college-aged females and to compare the observed AHI data across right and left feet.
Seventy-nine college-aged females served as study participants, and both feet were measured using the AHIMS in the seated and standing positions. The AHI was calculated as the ratio of the dorsum height of the foot at half the total foot length to the length of the foot from the heel to the base of the first metatarsophalangeal joint.
The mean ± SD AHI values for the left and right feet in the seated position were 0.355 ± 0.031 and 0.369 ± 0.034, respectively. The mean ± SD AHI values for the left and right feet in the standing position were 0.338 ± 0.031 and 0.343 ± 0.033, respectively. There were significant differences observed between the left and right feet for the seated (P < .001) and standing (P = .003) positions.
Normative values were established for college-aged females for the AHI using the AHIMS. Differences were noted between the right and left feet of the participants sampled. Although normative values were obtained, we caution against using these values to classify foot arch types based solely on a sample of the population studied. (J Am Podiatr Med Assoc 103(3): 213–217, 2013)
BACKGROUND: Normative studies on the Arch Height Index (AHI), Arch Rigidity Index (ARI), and arch stiffness have primarily focused on healthy populations, with little consideration of pathology. The purpose of this study was to create a normative sample of the aforementioned measurements in a pathological sample and to identify relationships between arch structure measurements and pathology. METHODS: AHI was obtained bilaterally at 10% and 90% weightbearing conditions using the Arch Height Index Measurement System (AHIMS). ARI and arch stiffness were calculated using AHI measurements. Dependent t-tests compared right and left, dominant and non-dominant, and injured and non-injured limbs. Measurements of the dominant foot were compared between sexes using independent t-tests. Relationships between arch stiffness and age, sex, and AHI were examined using the coefficient of determination (R2). One-way ANOVAs were used to determine differences between arch structure measurements and number of pathologies or BMI. RESULTS: A total of 110 participants reported either one (n=55), two (n=38), or three or more (n=17) pathologies. Plantar fasciitis (n=31) and hallux valgus (n=28) were the most commonly reported primary concerns. AHI, ARI, and arch stiffness did not differ between limbs for any comparisons, nor between sexes. Between subgroups of BMI and number of pathologies, no differences exist in AHI or ARI; however, BMI was found to have an impact on AHI (10%WB) and arch stiffness (p<.05). Arch stiffness showed a weak relationship to AHI, where a higher AHI was associated with a stiffer arch (R2=0.06). CONCLUSIONS: Normative AHI, ARI and arch stiffness values were established in a pathological sample with a large incidence of plantar fasciitis and hallux valgus. Findings suggest relationships between arch stiffness and both BMI and arch height; however, few trends were noted in AHI and ARI. Determining relationships between arch structure and pathology is helpful for both clinicians and researchers.
Background: Foot anthropometry may be altered during pregnancy. Pregnant women often report lower-extremity pain that may be related to these alterations. The Arch Height Index Measurement System is a common method of foot arch assessment; however, the required calipers are costly and are not widely available. Thus, we compared the reliability of a digital photogrammetry method of arch height index (AHI) assessment with that of the Arch Height Index Measurement System.
Methods: Ten pregnant women (mean ± SD: age, 29 ± 4 years; height, 166.9 ± 6.8 cm; weight, 63.3 ± 8.8 kg) in their second trimester were recruited to participate, along with a control group of 10 nulliparous weight-matched women (mean ± SD: age, 22 ± 2 years; height, 164.6 ± 4.8 cm; weight, 61.5 ± 8.1 kg). During the second and third trimesters, and once postpartum, AHI was assessed using calipers and using digital photogrammetry. Mixed model absolute agreement type intraclass correlation coefficient (ICC) was used to determine correlation between the two methods for sitting and standing AHI.
Results: The ICC results for sitting AHI only (0.819–0.968) were reasonable for clinical measures; ICC values for standing AHI (0.674–0.789) did not reach values deemed reasonable for clinical use.
Conclusions: Caliper and digital photogrammetry methods of AHI assessment are correlated in pregnant women; however, for standing AHI, the correlation is not sufficient for clinical use. Photogrammetry may still be appropriate for clinical use, as long as values from this method are not substituted directly for results obtained from calipers.
Background: Studies of arch height index (AHI), arch rigidity index (ARI), and arch stiffness have primarily focused on healthy populations. Normative values of the aforementioned measurements in a pathologic sample may be useful in identifying relationships between arch structure and pathology.
Methods: AHI was obtained bilaterally at 10% and 90% weightbearing conditions using the AHI measurement system. ARI and arch stiffness were calculated using AHI measurements. Dependent t tests compared right and left, dominant and nondominant, and injured and noninjured limbs. Dominant feet were compared between sexes using independent t tests. Relationships between arch stiffness and subcategories were examined using the coefficient of determination (R2). One-way analyses of variance determined differences between arch structure and number of pathologies or body mass index (BMI).
Results: A total of 110 participants reported one (n = 55), two (n = 38), or three or more (n = 17) pathologies. Plantar fasciitis (n = 31) and hallux valgus (n = 28) were the most common. AHI, ARI, and arch stiffness did not differ between limbs or sexes for any comparisons. Between subgroups of BMI and number of pathologies, BMI influenced AHI (10% weightbearing) and arch stiffness (P < .05). Arch stiffness showed a weak relationship to AHI, where a higher AHI was associated with a stiffer arch (R2 = 0.06).
Conclusions: Normative arch structure values were established in a pathologic sample with a large incidence of plantar fasciitis and hallux valgus. Understanding relationships between arch structure and pathology is helpful for clinicians and researchers.
Background: Research addressing the effect of running shoe type on the low- or high-arched foot during gait is limited. We sought 1) to analyze mean plantar pressure and mean contact area differences between low- and high-arched feet across three test conditions, 2) to determine which regions of the foot (rearfoot, midfoot, and forefoot) contributed to potential differences in mean plantar pressure and mean contact area, and 3) to determine the association between the static arch height index and the dynamic modified arch index.
Methods: Plantar pressure distributions for 75 participants (40 low arched and 35 high arched) were analyzed across three conditions (nonshod, motion control running shoes, and cushioning running shoes) during treadmill walking.
Results: In the motion control and cushioning shoe conditions, mean plantar contact area increased in the midfoot (28% for low arched and 68% for high arched), whereas mean plantar pressure decreased by approximately 30% relative to the nonshod condition. There was moderate to good negative correlation between the arch height index and the modified arch index.
Conclusions: Cushioning and motion control running shoes tend to increase midfoot mean plantar contact area while decreasing mean plantar pressure across the low- or high-arched foot. (J Am Podiatr Med Assoc 99(4): 330–338, 2009)
Medial longitudinal arch integrity after prolonged running has yet to be well documented. We sought to quantify changes in medial longitudinal arch kinematics before and after a 45-min run in healthy recreational runners.
Thirty runners performed barefoot seated, standing, and running trials before and after a 45-min shod treadmill run. Navicular displacement, arch lengthening, and the arch height index were used to quantify arch deformation, and the arch rigidity index was used to quantify arch stiffness.
There were no statistically significant differences in mean (95% confidence interval) values for navicular displacement (5.6 mm [4.7–6.4 mm]), arch lengthening (3.2 mm [2.6–3.9 mm]), change in arch height index (0.015 [0.012–0.018]), or arch rigidity index (0.95 [0.94–0.96]) after the 45-min run (all multivariate analyses of variance P ≥ .065).
Because there were no statistically significant changes in arch deformation or rigidity, the structures of a healthy, intact medial longitudinal arch are capable of either adapting to cyclical loading or withstanding a 45-min run without compromise.
Measurement of the medial longitudinal foot arch in children is a controversial topic, as there are many different methods without a definite standard procedure. The purpose of this study was to 1) investigate intraday and interrater reliability regarding dynamic arch index and static arch height, 2) explore the correlation between both arch indices, and 3) examine the variation of the medial longitudinal arch at two different times of the day.
Eighty-six children (mean ± SD age, 8.9 ± 1.9 years) participated in the study. Dynamic footprint data were captured with a pedobarographic platform. For static arch measurements, a specially constructed caliper was used to assess heel-to-toe length and dorsum height. A mixed model was established to determine reliability and variation.
Reliability was found to be excellent for the static arch height index in sitting (intraday, 0.90; interrater, 0.80) and standing positions (0.88 and 0.85) and for the dynamic arch index (both 1.00). There was poor correlation between static and dynamic assessment of the medial longitudinal arch (standing dynamic arch index, r = –0.138; sitting dynamic arch index, r = –0.070). Static measurements were found to be significantly influenced by the time of day (P < .001), whereas the dynamic arch index was unchanged (P = .845). This study revealed some further important findings. The static arch height index is influenced by gender (P = .004), whereas dynamic arch index is influenced by side (P = .011) and body mass index (P < .001).
Dynamic and static foot measurements are reliable for medial longitudinal foot arch assessment in children. The variation of static arch measurements during the day has to be kept in mind. For clinical purposes, static and dynamic arch data should be interpreted separately.
The correlation between arch structure and injury may be related to the fact that foot structure influences foot function. Foot structure is often defined by arch height, although arch flexibility may be just as important to form a more complete description. We propose an arch flexibility classification system, analogous to arch height classification, and then use the classification system to examine the relationship between arch flexibility and arch height.
Arch height index was calculated in 1,124 incoming military cadets, of whom 1,056 had usable data. By measuring arch height during both sitting and standing, a measurement of arch flexibility could also be calculated. These values were used to create five arch flexibility categories: very stiff, stiff, neutral, flexible, and very flexible. The distribution of arch flexibility types among arch height categories was statistically compared.
The goodness of fit test showed a disproportionate number of each arch flexibility type in each of the arch height categories (P < .01). The largest proportion of cavus feet was very stiff and the smallest proportion was very flexible. Conversely, the largest proportion of planus feet was very flexible and the smallest proportion was very stiff.
The results of this research support the common belief that cavus feet tend to be very stiff and planus feet tend to be very flexible.
Anthropometric status can influence gait biomechanics, but there is relatively little published research regarding foot and ankle characteristics in the obese pediatric population. We sought to compare the structural and functional characteristics of the foot and ankle complex in obese and non-obese children.
Twenty healthy children (ten obese and ten normal weight) were recruited for a cross-sectional research study. Anthropometric parameters were measured to evaluate active ankle dorsiflexion, arch height (arch height index, arch rigidity index ratio, and arch drop), foot alignment (resting calcaneal stance position and forefoot-rearfoot alignment in unloaded and loaded positions), and foot type (malleolar valgus index). Independent t tests determined significant differences between groups for all assessed parameters. Statistical significance was set at P < .0125.
Compared with non-obese participants, obese participants had significantly greater arch drop (mean ± SD: 5.10 ± 2.13 mm versus 2.90 ± 1.20 mm; P =.011) and a trend toward lower arch rigidity index ratios (mean ± SD: 0.92 ± 0.03 versus 0.95 ± 0.02; P = .013). In addition, obese participants had significantly less active ankle dorsiflexion at 90° of knee flexion versus non-obese participants (mean ± SD: 19.57 ± 5.17 versus 29.07 ± 3.06; P < .001). No significant differences existed between groups for any other anthropometric measurements.
The decreased active ankle dorsiflexion in the obese group can increase foot contact for a longer period of the stance phase of gait. Obese participants also presented with a more flexible foot when bearing weight. (J Am Podiatr Med Assoc 102(1): 5–12, 2012)