Eight week short-term effects of military training on foot structure and function in young adults.

Differences in foot pressures between Caucasians and Indians

INTRODUCTION AND OBJECTIVES: Healthy feet are important for overall health and well-being. Previous studies of older subjects showed that those with a lowered arch had an increased odds of having foot deformities, pain, and hyperpronation in gait. (1–3) No investigation to date has comprehensively characterized foot biomechanics in a large sample of healthy active young subjects. METHODS: Foot structure, function, and arch height flexibility (AHF) were measured in 1,052 incoming cadets to the United States Military Academy. Based on the previously established standing arch height index (AHI), 70% of subjects exhibited planus foot structures. (4,5) To examine the effects of AHF on dynamic barefoot plantar pressure, 1,414 planus feet were further categorized by AHF. Those that fell within the highest and the lowest quintiles were defined as flexible and stiff AHF, respectively, while the middle 3 quintiles were categorized as referent. RESULTS: Descriptive statistics and normality testing were performed using SPSS software version 22 (IBM, Chicago, IL, USA). A Generalized Linear Model with an identify link function was used to examine the effects of AHF category while accounting for potential dependence in bilateral data. The Wald Chi-square was calculated for each dependent variable with significance set at p < 0.05. Post hoc pairwise comparisons for all pairs were performed using the Generalized Chi Square test at P < 0.017. CONCLUSIONS: A significant difference was found in Center of Pressure Excursion Index (CPEI) and Peak Pressure (PP). Post hoc pairwise comparisons showed a significant difference between flexible versus stiff AHF: those with flexible AHF exhibited reduced CPEI (greater hyperpronation) while those with stiff AHF showed elevated PP. Results suggest that, in addition to AHI, the arch flexibility may affect dynamic foot function. This was a part of larger study. Additional studies are needed to examine the effects of AHI and AHF on regional plantar loading and overuse injuries.

Survival on controlled-release morphine versus controlled-release oxycodone in opioid-naïve patients with non-malignant pain: data from Danish national health registers

Song et al demonstrated that healthy subjects with planus and neutral foot type exhibited a distinguishable foot posture and dynamic foot function [1]. However, such a relationship has not been demonstrated in a large sample study. Foot structure was categorized into one of three foot types (cavus, neutral, and planus) based on the standing arch height index (AHI) in 1,054 incoming cadets at the US Military Academy (172 female, 18.5±1.1 years, 24.5±3.0 kg/m2) [2]. Five trials of barefoot dynamic planar pressure were obtained for each foot with the Novel emed-x (novel GmbH, Munich) using the two-step method for walking data acquisition. The Center of Pressure Excursion Index (CPEI, %) and the peak pressure (PP, in kiloPascal) were calculated for each trial. Analysis of Variance was performed across the foot type groups on the left foot. The cavus group exhibited the largest CPEI while the planus group demonstrated the smallest CPEI. The neutral group demonstrated the lowest peak pressure, which was significantly lower than the planus group. Results of this study provide additional evidence which support the link between the dynamic plantar pressure in gait and foot type biomechanics. Table 1 The mean Center of Pressure Excursion Index and the Peak Pressure are shown for three foot type groups. The analysis was limited to left foot only.

Static and dynamic effects of customized insoles on attenuating arch collapse with pregnancy: A randomized controlled trial

Objective: This study aims to investigate the patterns of plantar pressure distribution during running for patients with subtle cavus foot (SCF) and determine the impact of personalized orthopedic insoles with forefoot wedge on plantar pressure distribution in patients with SCF. Methods: Sixteen undergraduate participants (8 with SCF and 8 with normal arches) were recruited based on arch height index measurements. Two full-length insoles were personalized for each SCF based on plantar pressures during running, an arch support insole (ASI) and an arch support with forefoot wedge insole (AFI). Foot pressure data collected during different insole conditions in running, analyzing ten regions of footprints for peak pressure and pressure-time integral. Results: Higher peak pressures were observed in patients with SCF at the medial forefoot (p = 0.021), medial heel (p = 0.013), and lateral heel (p = 0.025), with a higher pressure-time integral also noted at the medial forefoot (p = 0.025), medial heel (p = 0.015), and lateral heel (p = 0.047) when compared to normal arches. Compared with without-insole, both the AFI and the ASI reduced peak pressure at the medial (AFI p = 0.011; ASI p = 0.024) and lateral heel (AFI p = 0.028; ASI p = 0.032). The AFI reduced peak pressure at the medial heel (p = 0.013) compared with the ASI. Both the AFI and the ASI reduced pressure-time integral at the medial forefoot (AFI p = 0.003; ASI p = 0.026), central forefoot (AFI p = 0.005; ASI p = 0.011), medial heel (AFI p = 0.017; ASI p = 0.005), and lateral heel (AFI p = 0.017; ASI p = 0.019). Additionally, the ASI reduced pressure-time integral at the big toe (p = 0.015) compared with the without-insole. Conclusion: These findings demonstrate that during running in patients with SCF, plantar pressures are concentrated in the forefoot and heel compared to the normal arch. The personalized orthotic insoles can be used to effectively redistribute plantar pressure in patients with SCF running. Incorporating a forefoot wedge to specifically address the biomechanical abnormalities associated with SCF may enhance the effectiveness of orthopedic insoles.

The average pressure distribution of the diabetic foot: Can it be used as a clinical diagnostic aid?

Comprehensive biomechanical characterization of feet in USMA cadets: Comparison across race, gender, arch flexibility, and foot types

Altering plantar load using foot orthoses (FOs) may alter the mechanical work required of internal structures and change the size of muscle and connective tissues. Skin sensitivity might also change as a result of altering mechanoreceptor stimulation. This study investigated the effects of FOs on foot soft tissue morphology and skin sensitivity over three months of use. Forty-one healthy participants wore prefabricated FOs (n = 23) or no insert (n = 18) for three months. The FOs were prescribed specific to each participant, using criteria of a change in peak pressure of 8% in the medial arch (pressure increase) and medial heel (pressure decrease). Ultrasound images were recorded pre- and post-FOs use to derive cross-sectional area and thickness of: abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and the Achilles tendon at the insertion and mid-portion. Plantar fascia thickness was measured at the insertion and midfoot. The minimal detectable difference was established in piloting (n = 7). Skin sensitivity was measured with monofilaments at the dorsum (between the hallux and second toe), medial and lateral heel, medial and lateral arch and the 1st metatarsal head. The FOs increased peak pressure by 15% in the medial arch and reduced it by 21% in the medial heel. None of the changes in soft tissue measurements was greater than the minimal detectable difference and there were no effects of group and time. Skin sensitivity decreased over time at the 1st metatarsal head for both groups, but there was no group effect. Using FOs over three months did not change the foot tissues nor skin sensitivity. This study challenges the notion that FOs make muscles smaller.

This study aimed to investigate the association of medial longitudinal arch (MLA) height and stiffness with lower extremity alignment, pain, and disease severity in patients with knee osteoarthritis (OA). This cross-sectional study included 90 patients (75 females, 15 males; mean age: 63.6±9.4 years; range, 50 to 90 years) diagnosed with knee OA according to the American College of Rheumatology criteria between December 2022 and June 2024. Medial longitudinal arch height and stiffness were assessed using the arch height index (AHI) method in both sitting and standing positions. The arch stiffness index (ASI) was calculated. The OA-related clinical outcomes included pain severity (numeric rating scale), Western Ontario and McMaster Universities Osteoarthritis Index scores, Kellgren-Lawrence grade, and tibiofemoral angles. Associations between MLA characteristics and OA parameters were examined. Low and high arch rates were 10% and 16%, respectively. No significant differences in OA clinical and radiological parameters were observed across different MLA types. Within-patient comparisons showed higher MLA height in the extremity with greater knee pain and more advanced OA. Correlation analyses indicated that increased ASI was associated with higher arch height and knee varus angles, suggesting a biomechanical interplay between MLA structure and knee joint alignment in advanced OA patients. In the early OA group, ASI was negatively correlated with knee pain severity. A higher medial arch and increased midfoot stiffness were associated with knee pain, radiological severity, and knee varus in patients with OA. These findings support the complex relationship between the foot arch structure and knee OA through the perspective of the lower extremity kinematic chain.

Physical skeletal loading can affect the bone mineral density (BMD). This study investigated the association between BMD and dynamic foot pressure during gait. A total of 104 patients (mean age, 62.6 ± 12.4 years; 23 male and 81 female) who underwent dual x-ray absorptiometry and pedobarography were included. BMD values of the lumbar spine, femoral neck, and total femur were assessed. The mean and maximum pressures were measured at the hallux, lesser toes, 1st metatarsal head, 2nd and 3rd metatarsal heads, 4th and 5th metatarsal heads, midfoot, medial heel, and lateral heel. Multivariable regression analysis was performed to identify factors significantly associated with BMD. The lumbar spine BMD was significantly associated with the mean pressure at the 4th and 5th metatarsal heads (p = 0.041, adjusted R 2 of model = 0.081). The femoral neck BMD was significantly associated with the maximum pressure at the 2nd and 3rd metatarsal heads (p = 0.002, adjusted R 2 = 0.213). The total femoral BMD also showed a significant association with the maximum pressure at the 2nd and 3rd metatarsal heads (p = 0.003, adjusted R 2 = 0.360). Foot plantar pressure during gait was significantly associated with BMD, and could potentially be used to predict the presence of osteoporosis. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Foot Type Biomechanics Part 2: Are structure and anthropometrics related to function?

Presentation 10: Evaluating Ankle-Foot Orthotics in Hemiplegic Stroke Patients Using Pedobarography

Women are disproportionately affected by musculoskeletal disorders. Parous women seem to be at a particularly elevated risk for structural and functional changes in the lower limbs. The combination of increased weight on the joints with potentially greater laxity during pregnancy could lead to permanent structural changes in the feet. Although arches may become lax during pregnancy, it is unknown whether the changes persist. The objective of this study was to determine whether arch height loss persists postpartum. Forty-nine women completed this longitudinal study. Static and dynamic arch measurements were collected in the first trimester and at 19 wks postpartum. Linear mixed models were used to determine whether outcome measures significantly changed overall or by parity. Arch height and rigidity indices significantly decreased, with concomitant increases in foot length and arch drop. The first pregnancy accounted for the reduction in arch rigidity and the increases in foot length and arch drop. No changes were detected in the center of pressure excursion index. Pregnancy seems to be associated with a permanent loss of arch height, and the first pregnancy may be the most significant. These changes in the feet could contribute to the increased risk for musculoskeletal disorders in women. Further research should assess the efficacy of rehabilitative interventions for prevention of pregnancy-related arch drop.

Effect of Gender and Load Conditions on Foot Arch Height Index and Flexibility in Japanese Youths