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: 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.
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.
Patellofemoral pain (PFP) is a common injury, particularly in females. Foot pronation may promote knee and hip transverse plane joint kinematics during gait thought to contribute to PFP. Greater knowledge of plantar loading characteristics in females with PFP may be valuable to provide a basis for clinical decisions regarding footwear and foot orthoses. The purpose of this study was to compare plantar loading distribution in females with and without PFP during gait.
Plantar pressure during walking was recorded from 19 females with PFP and 20 females without PFP. Contact area, peak force, and force-time integral were evaluated in ten plantar areas. Arch index was also calculated from contact area data during gait.
Contact area in females with PFP was 9% smaller in the first metatarsal region (P = .039) and 20% smaller in the midfoot region (P = .042) than in females without PFP. Peak force was 31% lower in the midfoot region for females with PFP (P = .027) and 13% lower in the first metatarsal region (P = .064). Force-time integral was 18% lower in the first metatarsal region in females with PFP (P = .024). Females with PFP demonstrated a lower arch index (suggesting a higher arch) (P = .028).
Decreased medial forefoot loading and decreased midfoot contact suggest decreased foot pronation during gait in females with PFP relative to females without PFP. Decreased foot pronation may foster increased patellofemoral joint loading rates. These data contribute to rationale for footwear modifications to modify plantar loading characteristics in people experiencing PFP.
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.
A study on the effect of sectioning the plantar fascia on the range of motion at the first metatarsophalangeal joint is presented. Dorsiflexion and plantarflexion range-of-motion data from 18 patients who had no first metatarsophalangeal joint pathology and had undergone an in-step plantar fasciotomy for recalcitrant plantar fasciitis were analyzed. The average increase in dorsiflexion of the first metatarsophalangeal joint after plantar fascia release was 9.8°, which represented a statistically significant increase using a paired t-test. Thus release of the plantar fascia can be considered a potential adjunct to hallux limitus surgery. (J Am Podiatr Med Assoc 92(10): 532-536, 2002)
Previous studies have reported conflicting results on whether different foot placements in standing can affect static measurements of foot posture. We sought to determine whether three measurements of static foot posture could be consistently measured in three different foot placements while standing.
Twenty individuals, 12 women and eight men, with a mean age of 24.8 years consented to participate. Two raters assessed the dorsal arch height, midfoot width, and heel width of each foot while the participant stood in the following three foot placements: a standardized placement, a participant-determined placement after marching in place, and a rater-determined foot placement based on observation of the participant's angle of gait and base of support while walking.
All three measurements of static foot posture were shown to have high levels of intrarater and interrater reliability. Significant differences in the measurements of dorsal arch height, midfoot width, and heel width were found among all three of the foot placements. There were no differences between the two raters for any of the three measurements of foot posture.
Based on these findings, we recommend that clinicians perform measurements of static foot posture using the same standing foot placement between sessions to ensure a high level of measurement consistency.
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.
In a previous pilot study of “cruisers” (nonindependent ambulation), “early walkers” (independent ambulation for 0–5 months), and “experienced walkers” (independent ambulation for 6–12 months), developmental age significantly affected the children’s stability when walking and performing functional activities. We sought to examine how shoe structural characteristics affect plantar pressure distribution in early walkers.
Torsional flexibility was evaluated in four shoe designs (UltraFlex, MedFlex, LowFlex, and Stiff based on decreasing relative flexibility) with a structural testing machine. Plantar pressures were recorded in 25 early walkers while barefoot and shod at self-selected walking speeds. Peak pressure was calculated over ten masked regions for the barefoot and shod conditions.
Torsional flexibility, the angular rotation divided by the applied moment about the long axis of the shoe, was different across the four shoe designs. As expected, UltraFlex was the most flexible and Stiff was the least flexible. As applied moment increased, torsional flexibility decreased in all footwear. When evaluating early walkers during gait, peak pressure was significantly different across shoe conditions for all of the masked regions. The stiffest shoe had the lowest peak pressures and the most flexible shoe had the highest.
It is likely that increased shoe flexibility promoted greater plantar loading. Plantar pressures while wearing the most flexible shoe are similar to those while barefoot. This mechanical feedback may enhance proprioception, which is a desirable attribute for children learning to walk. (J Am Podiatr Med Assoc 103(4): 297–305, 2013)
Plantar pressure measurement is effective for assessing plantar loading and can be applied to evaluating foot performance. We sought to explore the characteristics of plantar pressures in elite sprinters and recreational runners during static standing and walking.
Arch index (AI) values, regional plantar pressure distributions (PPDs), and footprint characteristics were examined in 80 elite sprinters and 90 recreational runners using an optical plantar pressure measurement system. Elite sprinters' pain profiles were examined to evaluate their most common pain areas.
In recreational runners, AI values in males were in the normal range and in females were high arch type. The AI values were significantly lower in elite sprinters than in recreational runners. In elite sprinters, particularly males, the static PPD of both feet was higher at the medial metatarsal bone and the lateral heel and lower at the medial and lateral longitudinal arches. Elite male sprinters' PPD of both feet was mainly transferred to the medial metatarsal bone and decreased at the lateral longitudinal arch and the medial heel during the midstance phase of walking. The lateral knee joint and biceps femoris were the most common sites of musculoskeletal pain in elite sprinters.
Elite sprinters' AI values could be classified as high arches, and their PPD tended to parallel the features of runners and high-arched runners. These findings correspond to the profile of patellofemoral pain syndrome (PFPS)–related plantar pressure. The pain profiles seemed to resonate with the symptoms of high-arched runners and PFPS. A possible link between high-arched runners and PFPS warrants further study.