Descriptive Study of the Influence of Foot Type on Physical Characteristics, Laxity, Strength and Baropodometry in Children Aged 5 to 10 Years

Abstract

Background: Foot morphology in children is a crucial factor influencing multiple aspects of their physical development. Between the ages of 5 and 10 years, the critical period of child development is when the movement and stability patterns are consolidated that can affect their long-term physical performance and quality of life. The aim of this study is to analyze how the type of foot influences different physical characteristics, laxity, strength, motor tests, and baropodometric variables in children aged 5 to 10 years. Methods: A cross-sectional study involving 196 children was conducted. Different physical characteristics, laxity, strength, motor tests, and baropodometric variables of the sample were analyzed for age and Foot Posture Index (FPI). Results: Differences in all variables were examined by age and FPI. Statistical analysis showed a moderate to high correlation (r > 0.6, p < 0.01) between FPI and the relaxed calcaneal stance position (RCSP) test. Some significant differences were also found in variables related to foot pronation and supination. These results provide valuable information for understanding differences in motor and functional development during childhood and pre-adolescence. Conclusions: The findings highlight the variability in physical and functional development between age and foot type groups, highlighting the importance of considering these differences in the assessment and management of foot-related conditions and biomechanics in childhood. Foot type significantly influences children’s growth and development.

1. Introduction

Childhood is a crucial stage in the physical and motor development of children, with each growth phase having significant implications for the health and overall well-being of this special population. One of the less studied but equally fundamental aspects is the type of foot. The type of foot a child has can significantly influence various physical and functional characteristics during growth [1]. As children develop their motor skills and their ability to interact with their environment, the type of foot—whether pronated, supinated, or neutral—can play a decisive role in their posture, gait, and stability [2]. Therefore, we find that the morphology of children’s feet is a crucial factor influencing multiple aspects of their physical development [3].

To evaluate foot type in childhood, there is a tool considered the “gold standard”, the Foot Posture Index (FPI). This is an effective, easy-to-use, and reliable clinical tool that has shown great consistency among different evaluators when applied to the assessment of children’s feet. This index quantifies the type of foot a child has, that is, whether it is pronated, supinated, or neutral [4].

Physical characteristics such as weight and gender, in addition to joint laxity, muscle strength, motor skills, and baropodometric characteristics, provide valuable information about a child’s motor development. These relationships are well-studied in the adult population [5], but not as well-studied in the pediatric population [6].

Regarding physical characteristics, variations in gender, age, and weight can influence foot size and posture, bone structure, as well as plantar pressures as the child grows [1,3].

Joint laxity, or flexibility of the joints, is a crucial aspect that can be influenced by foot structure [7]. Children with more flexible or stiffer feet may experience differences in their range of motion and comfort during daily activities [8]. Laxity can affect how a child walks, runs, or plays, which has implications for their motor development and participation in physical activities; it can also predispose them to future injuries [8]. Another critical dimension that can affect a child’s functional development and may be influenced by foot posture is muscle strength. Children with different foot types may exhibit variations in the strength of the intrinsic foot muscles, which can impact their performance in sports activities and their ability to maintain proper posture [9]. Foot muscles play a crucial role in stability and movement, and the influence of foot type on muscle strength can have significant effects on gait and the ability to maintain balance [7,8,9].

Regarding baropodometry, we also find that gait patterns are usually associated with different foot types, and these patterns can reveal a lot of information about pressure distribution and adaptation to different surfaces [10]. Possible movement misalignments could trigger postural or coordination problems [11]. A child’s ability to maintain balance and adapt to changes in the environment is fundamental for their safety and physical development, meaning that maintaining good balance is vital to prevent falls or avoid future injuries [12].

Considering all the aforementioned, it is observed that between the ages of 5 and 10, children experience significant changes in their body structure and motor skills, making the study of their foot type particularly relevant for approaches in clinical practice [13]. During this critical period of childhood development, movement and stability patterns are consolidated, which can affect their physical performance and quality of life in the long term [1,3]. Therefore, the main clinical implication is to determine whether the type of foot a child has can influence their proper development. Early detection, particularly of a supinated or pronated foot, would allow us to assess the most appropriate treatment or prevention strategy. In this context, understanding the influence of foot type on various physical characteristics, i.e., how the foot type interacts with the structure and function of the child, becomes fundamental to promoting healthy and balanced development.

Over the course of this year, several studies have been published that address how footwear [14,15], habits [16], and environmental factors [17] can influence the development of children’s feet, underlining the relevance and necessity of this work. It is crucial to investigate how foot type influences the key physical characteristics such as laxity, strength, and baropodometric variables in children aged 5–10 years, a crucial stage in their motor development. Although there are studies in the literature on the impact of environmental factors and footwear on children’s foot development [14,15,16,17], there is a lack of comprehensive studies analysing how different foot types affect specific physical characteristics such as strength and laxity, which are determinants of motor performance and overall locomotor health.

Therefore, this study aims to analyze in children aged 5 to 10 years (by age and FPI) how foot type influences different physical characteristics (gender, age, and BMI), laxity, strength, motor tests, and various baropodometric variables.

2. Materials and Methods

2.1. Design and Participants

This descriptive observational study was conducted with a total of 118 girls and 78 boys, making a total of 196 children. These children were evaluated in Murcia (Spain) during the year 2022. The sample size of 196 participants was determined by the statistical program EPITAD. The program was set to have a high effect size (i.e., detecting changes greater than 0.8) and an error rate of type I of 0.05 and a type II error rate of 0.2.

Since the main variable in this study was the FPI, the age range selected for this study was 5 to 10 years, a range that ensures the validity of the FPI [4]. This study was conducted following the principles of Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) [18] and the ethical principles established in the Declaration of Helsinki. Additionally, this study received approval from the Ethics Committee of the San Antonio de Murcia University (Ethics Committee Code: CE022205) and the ethical approval of the parents or legal guardians of the children, who signed an informed consent form.

Children aged between 5 and 10 years, without foot pain, and whose parents or guardians gave consent, were selected as the sample. Before participation, parents or guardians received information about this study and completed a questionnaire. Children with recent lower limb injuries, congenital structural alterations affecting the distal areas of the ankle joint, pathological flat foot (FF) caused by cerebral palsy, foot or lower limb surgeries, or genetic, neurological, or muscular pathologies were excluded from this study.

The evaluations were carried out at Colegio San Francisco de Asis, in Lorca (Murcia). Evaluations were conducted on each child in the morning according to a fixed schedule over five months. Before the tests, demographic and anthropometric data were collected from all the children. Each child was assigned a unique code to protect their privacy. During the examination, children were asked to remove their shoes and socks to be barefoot and to wear comfortable clothing, such as T-shirts and shorts. Two experienced podiatrists conducted the evaluations simultaneously. Although most tests showed high reliability in measurements, if the two podiatrists did not agree on a score, a third podiatrist was consulted to reach a consensus. An independent podiatrist, not involved in the evaluations, was responsible for data analysis.

Before starting the test, each test was explained and demonstrated to the children. Each test item had to be performed three times, and the average of the obtained measurements was calculated. Throughout the procedure, children received standardized verbal encouragement and support. If a child made an error in the procedure, the instructions and demonstrations were repeated, allowing the child to retry the test; each child could make up to 5 errors. If a child made more than five errors, they were excluded from the analysis. All examined children successfully completed all measurements, resulting in no missing data.

Given that this study involves the participation of minors, the ethical principles established for research involving children were strictly followed. Written informed consent was obtained from the parents or legal guardians of all participants, who were duly informed about the objectives, procedures, and possible risks of this study. In addition, the right of minors to withdraw from this study at any time without repercussions was ensured. In terms of data protection, the confidentiality and anonymity of the participants was guaranteed by encrypting the information collected, in compliance with current personal data protection regulations. The data were stored in secure systems and are accessible only to the research team.

2.2. Measurement of Variables

2.2.1. Physical Characteristics

Demographic data were collected, including gender, age, and Body Mass Index (BMI) (BMI = weight (kg)/height (m)²). Information on gender and date of birth was obtained from the parents, and weight was recorded using the calibrated digital scale “Digital Pegasus Scales” with a margin of error of 0.05 kg and height with a calibrated portable SECA 7710 stadiometer, equipped with a bubble level on the arm for improved accuracy. Children were asked to relax, and all demographic and joint mobility measurements were conducted without causing any discomfort or pain.

2.2.2. Type of Foot

To determine the type of foot each child had, the FPI-6 [4] was used. This was conducted with the children barefoot, standing, and relaxed. Six criteria were analyzed (through visual observation and manual manipulation), as follows:

• Palpation of the talar head;
• Supra and inframalleolar curvature;
• Calcaneal position in the frontal plane;
• Talonavicular prominence;
• Medial arch congruence;
• Forefoot abduction/adduction.

Each criterion was scored on a scale from +2 (pronation) to −2 (supination), with 0 indicating a neutral position. The scores for each criterion were summed to obtain a total value, which determined the categories of foot posture, ranging from very supinated to very pronated.

Interobserver reliability of the FPI in children aged 5 to 16 years is very high, with a consistent weighted Kappa coefficient of 0.86, in addition to excellent intraobserver reliability, with an intraclass correlation coefficient (ICC) between 0.93 and 0.94 [4].

2.2.3. Laxity

Lunge Test

This test measures the range of ankle dorsiflexion. It is measured with the child bearing weight and the knee flexed. The child stands on a solid, flat surface, facing a vertical wall. The foot to be evaluated is perpendicular to the wall, while the other foot is placed in a comfortable and stable position. The child pushes the knee forward while keeping the heel in contact with the ground. The maximum forward angle of the tibia relative to the vertical was measured as an indication of ankle dorsiflexion, using the digital inclinometer “Smart Tool™ Factory” (Istanbul, Turkey) applied to the anterior part of the tibia. Intratester intraclass correlation coefficients were 0.98, and intertester reliability reached an excellent weighted Kappa value (Kw = 0.97) [19]. Data provided were in degrees (°). A higher ° indicates a greater range of ankle dorsiflexion.

Rest Calcaneal Stance Position (RCSP)

This test measures the position of the calcaneus of each foot. During each measurement, the child was lying prone, with the ankle flexed at 90°, ensuring the heel was aligned perpendicularly with the leg in the sagittal plane. The back of the calcaneus of both feet was then marked with a fine marker. The angle between the bisected line of the calcaneus and the perpendicular to the ground was measured in °. Intraobserver reliability for the RCSP in the pediatric population showed a good weighted Kappa value (Kw = 0.61 to 0.90) [20]. A more negative RCSP value suggests a more pronounced calcaneal pronation.

Lower Limb Assessment Score (LLAS)

This scale evaluates the hypermobility of the lower limbs (LL). Each LL receives a maximum score of 12 points. A score of 7 out of 12 indicates joint hypermobility. The LLAS scale is reliable with an ICC of 0.84 [21].

2.2.4. Timed Motor Function Tests

The interpretation of the following two tests implies that the greater the distance covered in the 6 min Walking Test (6MWT) and the shorter the time in the Time to Run 10 m (10MRT), the better the motor performance.

MWT

This test was conducted in a covered corridor 30 m long, with marks every 2 m on a flat surface, where the child walked for 6 min, being able to rest during the test. The test was performed according to the recommendations of the American Thoracic Society [22]. Data obtained were expressed in meters (m).

10MRT

The time in seconds that the child needed to cover a distance of 10 m as quickly as possible was calculated. The test was conducted on a 30 m long surface. The stopwatch was started when the evaluator gave the signal “Go” and stopped when both of the child’s feet crossed the finish line [23]. This test was measured in seconds (sec).

2.2.5. Foot Strength

Isometric muscle strength was measured with a handheld dynamometer from the Lafayette Instrument Company, model 01160, Lafayette, IN, USA. This device is factory-calibrated with a sensitivity of 0.1 kg and a measurement range of 0 to 200 kg. Each child sat on an examination table with hips flexed, knees extended, and back supported. Isometric muscle strength for foot inversion and eversion, as well as ankle plantarflexion and dorsiflexion, was measured, taking data from both feet. Strength was measured in Newtons (N). Higher values indicate more strength. The position of the dynamometer for each of the evaluated foot movements was as follows:

-

Inversion: positioned medially over the base of the first metatarsal.

-

Eversion: positioned laterally over the base of the fifth metatarsal.

-

Ankle plantarflexion: positioned on the plantar part of the head of the 2nd and 3rd metatarsals.

-

Ankle dorsiflexion: positioned on the dorsal part of the head of the 2nd and 3rd metatarsals.

At the start of the test, the reference position was with the ankle and subtalar joint in neutral position. The “make” test method was used, where the operator’s hand kept the dynamometer fixed while the child exerted maximum force against it.

Three consecutive contractions lasting between 3 and 5 s were performed for each movement in a random order, and the average of these contractions was calculated. Additional repetitions were made if the evaluator considered the child’s effort to be below their capacity or if the movement was not performed correctly.

The ICC and the 95% confidence interval (CI) showed excellent results (ICC = 0.88 to 0.95, 95% CI = 0.75 to 0.98) for all muscle groups evaluated. The measurement error was low for all variables (SEM = 0.3 to 0.7 kg) [24].

2.2.6. Baropodometry

The RSscan Footscan^® 9 platform was used for baropodometric analysis. The platform measures 578 mm × 418 mm × 12 mm and has 4096 sensors arranged in a 64 × 64 matrix. Each sensor measures 7.62 mm × 5.08 mm, with an active area of 488 mm × 325 mm. The accuracy range is 1 to 127 N/cm², and the data acquisition frequency is 500 Hz with a resolution of 10 bits.

According to the manufacturer’s instructions, the platform was calibrated before each session. Before data collection, the children were given the opportunity to familiarize themselves with the platform to gain confidence. Additionally, for gait, familiarization tests were conducted to ensure that the children walked comfortably and naturally.

Three baropodometric measurements and three stabilometric measurements were performed in a standing position with eyes open, each lasting 60 s, for each child, with a one-minute rest between measurements. The children were asked to stand on the platform with a natural Fick angle, arms at their sides, feet aligned, and looking at a fixed point at eye level, 3.8 m away.

For dynamic gait measurements, the pressure platform was placed in the center of a 10 m long corridor, and the children were instructed to walk barefoot down the corridor ten times. To maintain a constant speed before stepping on the platform, the children had to step on it no earlier than their fourth step. Measurements were obtained by combining all tests for each foot, ensuring 8 to 10 valid footprints per child. Valid footprints were those in which the child had maintained balance while walking (1), was not distracted (such as looking around or talking) during walking (2), and when the entire plantar area was captured (3). The first two criteria were monitored during the scan, and the third criterion was visually evaluated later by the same researcher. To avoid issues with paired data, the plantar pressure results of the left and right feet were averaged into a single observation.

The reliability of the Footscan^® system (RSscan International, Olen, Belgium) has been confirmed in various studies, showing good to excellent ICC for intra- and inter-evaluator assessments (ICC from 0.81 to 0.86 and from 0.87 to 0.95, respectively) in plantar pressure variables [25]. The variables extracted from the baropodometry were as follows:

Dynamic 2D

Dynamic 2D analysis focuses on foot rocking movements and provides information about the subtalar joint angles and the flexibility of the left and right feet. The following measurements are expressed in °:

-

Fick Angle: The angle of the subtalar joint. It measures the rearfoot movement in the frontal plane relative to the ground during the initial contact phase. A higher value indicates a more pronated rearfoot.

-

Minimum–Maximum Pronation: Represents the flexibility of the subtalar joint (pronation excursion). The measurements indicate the maximum supination and pronation positions of the rearfoot relative to the ground during the initial contact phase.

During Stance Phase of Gait

Foot time analysis identifies different events and phases during foot movement for both the right and left feet. Each event and phase are expressed in milliseconds and as a percentage of the total movement time. The events and phases for both feet are as follows:

-

Forefoot Contact Phase (ms): duration of foot contact phase.

-

Foot Flat Phase (ms): the duration between the initial forefoot contact event and the heel-off event.

-

Forefoot Push Off Phase (ms): the duration between the heel-off event and the last foot contact event.

Stabilometric Variables (Static)

The following parameters were considered: Percentage of pressure distribution between the left and right legs, as well as between the forefoot and the rearfoot. The left forefoot (C1), right forefoot (C2), left rearfoot (C3), and right rearfoot (C4) were also evaluated.

Gravity Center Variables

The following data were also extracted from the center of gravity:

-

Minimum and maximum y-axis and x-axis: the minimum and maximum position, measured in mm for the x and y coordinates.

-

Distance traveled and right left foot: the length of the center of pressure line, measured in mm.

-

Ellipse area right and left: the area of the center of pressure ellipse, measured in mm².

-

Principal and second axis ellipse left and right: length of the major-minor axis of the center of pressure ellipse, measured in mm.

Stabilometric Variables of Each Foot

Finally, the maximum and minimum ° and mm of the center of pressures (CoP) were extracted.

2.3. Statistical Analyses

All variables were checked for homogeneity of variances and normal distribution using statistical and graphical procedures. Most of the variables showed significant differences (p < 0.05) in the K-S test and Levene’s test, so it could be confirmed that there was no normal distribution or homogeneity of variances, which resulted in performing non-parametric tests. Comparison of means of independent samples was performed using U of the Mann–Whitney test. For statistical analysis, the sample was grouped into 2 subgroups by age range (5 to 7 years and 8 to 10 years) and these subgroups were further subdivided based on the FPI variable into normal FPI, supinated FPI, and pronated FPI. These 2 groups were created to take into account those children who did not yet have a mature gait pattern and who had not yet completed the maturation process, from those who were, on the contrary, in the process of completing ossification and who already had a mature gait pattern. Additionally, a Pearson correlation test was conducted between the FPI and the rest of the variables studied. Likewise, Fisher’s exact corrections were performed to see if there were proportionality differences in the sample number between genders.

All analyses were performed using the SPSS software (IBM SPSS Statistics: V.24, Chicago, IL, USA) for Windows version 27.0.1. The level of significance was set at p < 0.05.

3. Results

Firstly, the average age of the participants was 7.6 years, with an age range between 5 and 10 years. Of the total participants, 60.2% were girls and 40.8% were boys. The average BMI of the children was 17.8 kg/cm².

In comparison of the means between the normal FPI group versus the pronated FPI group aged 8 to 10 years, significant differences were found in height (1.37 ± 0.07 vs. 1.34 ± 0.06; p = 0.039). That is, children with flat feet (FF) were shorter in height than children with neutral feet.

Although the other data are not statistically significant, it can be observed in the groups aged 5 to 7 years and 8 to 10 years that having a more pronated FPI is associated with a higher BMI compared to a more neutral foot.

In the age group of 5 to 7 years, there were a total of 39 children with FF and 74 with neutral feet. As the children grew older, the number decreased, with 29 children with FF and 51 children with normal feet observed. As for supinated feet, we found only one child with high arches aged 5 to 7 years and two children with supinated feet aged 8 to 10 years.

The results can be seen in

Table 1. Physical characteristics of the sample by age and FPI in children.

	5 to 7 Years					8 to 10 Years
Physical Characteristic Variables	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated
	n = 114	n = 74	n = 1	n = 39	p	n = 82	n = 51	n = 2	n = 29	p
	M/F	M/F	M/F	M/F		M/F	M/F	M/F	M/F
Age (years)	6.55 ± 0.75	6.48 ± 0.72	N/A	6.66 ± 0.79	0.561	9.13 ± 0.58	9.04 ± 0.59	8.75 ± 0.41	9.32 ± 0.54	0.221
Weight (kg)	24.52 ± 5.84	24.09 ± 4.93	N/A	25.3 ± 7.32	0.433	34.99 ± 7.81	34.47 ± 8.43	36.8 ± 9.76	35.79 ± 6.69	0.480
Height (m)	1.19 ± 0.06	1.19 ± 0.06	N/A	1.19 ± 0.07	0.482	1.36 ± 0.07	1.37 ± 0.07	1.46 ± 0.03	1.34 ± 0.06	0.039 *
BMI (kg·m−2)	17.08 ± 2.90	16.86 ± 2.41	N/A	17.53 ± 3.7	0.550	18.79 ± 3.45	18.28 ± 3.43	17.19 ± 3.91	19.8 ± 3.34	0.109
Gender, n (%)	55 M/59 F	35 M/39 F	0 M/1 F	20 M/19 F	N/A	23 M/59 F	14 M/37 F	1 M/1 F	8 M/21 F	N/A

BMI = body mass index; F = female; FPI = Foot Posture Index; Kg = kilograms; n = number of children; N/A = not applicable (with n < 2, descriptive statistics are meaningless); M = male; m = metres; * = p < 0.05.

.

Regarding laxity, when comparing the averages between the groups of children aged 5 to 7 years with a normal FPI and those with a pronated FPI, very significant differences were observed in the RCSP measurements for both the right foot (3.24 ± 1.89 vs. 6.64 ± 2.7; p = 0.000) and the left foot (3.38 ± 2.16 vs. 6.49 ± 2.43; p = 0.000). For the group of children aged 8 to 10 years, comparing the averages between those with a normal FPI and those with a pronated FPI, very significant differences were found in the RCSP measurements for both feet; right foot (3.9 ± 1.93 vs. 5.72 ± 2.15; p = 0.004) and left foot (3.78 ± 1.86 vs. 5.59 ± 2.41; p = 0.001). This means that children with a higher FPI, that is, with more pronated feet, have a greater RCSP.

Although we did not find significant differences, we can observe that more pronated feet have less dorsiflexion of the ankle in children aged 5 to 7 years, an aspect that reverses as the child grows. Similarly, regarding LL hyperlaxity, we observed that having a higher FPI tends to be associated with greater hyperlaxity, although not significantly.

These results can be seen in

Table 2. Laxity variables of the sample by age and FPI in children.

	5 to 7 Years					8 to 10 Years
Laxity Variables	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated
	n = 114	n = 74	n = 1	n = 39	p	n = 82	n = 51	n = 2	n = 29	p
Lunge test R (°)	52.25 ± 6.40	52.84 ± 5.99	N/A	51.05 ± 7.1	0.136	47.63 ± 5.91	48.06 ± 6.15	47 ± 0	46.93 ± 5.73	0.539
Lunge test L (°)	52.44 ± 5.85	52.89 ± 5.53	N/A	51.49 ± 6.42	0.189	47.57 ± 6.38	47.78 ± 6.82	48 ± 1.41	47.17 ± 5.85	0.935
RCSP R (º)	4.39 ± 2.72	3.24 ± 1.89	N/A	6.64 ± 2.7	0.000 **	4.45 ± 2.28	3.9 ± 1.93	0 ± 1.41	5.72 ± 2.15	0.004 **
RCSP L (°)	4.43 ± 2.70	3.38 ± 2.16	N/A	6.49 ± 2.43	0.000 **	4.33 ± 2.32	3.78 ± 1.86	0 ± 1.41	5.59 ± 2.41	0.001 **
LLAS R (Score)	6.16 ± 3.53	5.82 ± 3.46	N/A	6.74 ± 3.68	0.241	4.87 ± 3.5	4.16 ± 3.25	5 ± 7.07	6.1 ± 3.49	0.113
LLAS L (Score)	6.08 ± 3.54	5.77 ± 3.45	N/A	6.87 ± 3.61	0.277	4.9 ± 3.45	4.25 ± 3.2	5 ± 7.07	6.03 ± 3.51	0.150

° = degrees; FPI = Foot Posture Index; L = left; LLAS = Lower Limb Assessment Score; n = number of individuals; N/A = not applicable (with n < 2, descriptive statistics are meaningless); R = right; RCSP = relaxed calcaneal stance position; ** p < 0.01.

.

A moderate to high correlation was found between the FPI and the RCSP test, with correlation coefficients (r) above 0.6 and p-values less than 0.01, indicating a statistically significant relationship. This suggests that RCSP can serve as a reasonable substitute for the FPI. The rest of the variables did not show significant correlations (see Supplementary Table S1).

Regarding the motor function tests, the results obtained are very similar to each other. According to the statistical analysis conducted, no statistically significant differences were found in the motor function tests (p > 0.05). This means that having a pronated or supinated foot type does not imply changes in the child’s motor function.

The data can be seen in

Table 3. Timed motor function test of the sample by age and FPI in children.

	5 to 7 Years					8 to 10 Years
Timed Motor Function Tests Variables	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. pronated	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated
	n = 114	n = 74	n = 1	n = 39	p	n = 82	n = 51	n = 2	n = 29	p
6MWT (m)	456.65 ± 56.96	455.65 ± 53.49	N/A	458.72 ± 64.38	0.923	472.77 ± 52.37	474.02 ± 55.15	480 ± 0	470.07 ± 49.89	0.967
10MRT (seg)	3.37 ± 0.43	3.41 ± 0.45	N/A	3.31 ± 0.39	0.233	3.18 ± 0.48	3.16 ± 0.41	3.15 ± 0.18	3.23 ± 0.6	0.689

FPI = Foot Posture Index; L = left; n = number of individuals; N/A = not applicable (with n < 2, descriptive statistics are meaningless); m = metres; R = right; seg = seconds; 6MWT = 6 min Walking Test; 10MRT = Time to Run 10 m.

.

In the comparisons between the group with a normal FPI (aged 5 to 7 years) and those with a pronated FPI, significant differences were found in the plantar flexion strength of the left foot (10.28 ± 2.5 vs. 11.5 ± 3.56; p = 0.048). This means that children with a pronated FPI have greater plantar flexion strength than children with a neutral foot.

Other important observations, although not showing significant differences, are that a higher FPI corresponds to greater foot strength. Conversely, a lower FPI (the more supinated the foot is) corresponds to less foot strength in the child.

These data can be found in

Table 4. Strength variables of the sample by age and FPI in children.

	5 to 7 Years					8 to 10 Years
Foot Strength Variables	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated
	n = 114	n = 74	n = 1	n = 39	p	n = 82	n = 51	n = 2	n = 29	p
Eversion R (N)	7.5 ± 1.27	7.35 ± 1.1	N/A	7.78 ± 1.53	0.945	11.29 ± 2.22	11.16 ± 2.25	9.19 ± 1.11	11.68 ± 2.17	0.547
Eversion L (N)	6.66 ± 1.34	6.6 ± 1.19	N/A	6.8 ± 1.59	0.993	10.61 ± 2.14	10.47 ± 2.1	9.03 ± 1.27	10.96 ± 2.25	0.482
Inversion R (N)	6.52 ± 2.5	6.58 ± 2.95	N/A	6.45 ± 1.34	0.221	10.67 ± 2.63	10.52 ± 2.73	8.67 ± 2.26	11.08 ± 2.44	0.530
Inversion L (N)	5.95 ± 1.35	5.92 ± 1.41	N/A	6.03 ± 1.26	0.723	10.29 ± 2.64	10.24 ± 2.79	8.64 ± 2.5	10.47 ± 2.39	0.886
Plantarflexion R (N)	11.26 ± 3	10.87 ± 2.5	N/A	12.02 ± 3.73	0.230	22.3 ± 7.05	21.24 ± 7.04	17.17 ± 6.41	24.52 ± 6.69	0.081
Plantarflexion L (N)	10.68 ± 2.94	10.28 ± 2.5	N/A	11.5 ± 3.56	0.048 *	22.2 ± 7.07	20.96 ± 6.69	19.42 ± 9.92	24.57 ± 7.2	0.089
Dorsiflexion R (N)	6.67 ± 1.17	6.58 ± 1.19	N/A	6.83 ± 1.13	0.399	9.69 ± 1.7	9.54 ± 1.69	9.04 ± 2.31	10 ± 1.71	0.550
Dorsiflexion L (N)	6.57 ± 1.9	6.36 ± 1.15	N/A	7.02 ± 2.78	0.479	9.43 ± 1.79	9.3 ± 1.82	9.55 ± 2.23	9.66 ± 1.76	0.421

FPI = Foot Posture Index; L = left; N = Newton; n = number of individuals; N/A = not applicable (with n < 2, descriptive statistics are meaningless); R = right; * = p < 0.05.

.

Finally, regarding the baropodometric variables, comparisons of means between the normal FPI group and the pronated group (aged 5 to 7 years) found significant differences in the maximum supination of the right foot (9.53 ± 4.641 vs. 10.74 ± 5.38; p = 0.027). This indicates that children with a tendency towards greater pronation often compensate for this excessive pronation with more pronounced supination.

In the comparison of means between the normal FPI group and the pronated group (aged 8 to 10 years), very significant differences were found in the forefoot push-off phase (p < 0.01). Significant differences were also found (p < 0.05) in the full foot support phase. This means that children with FF spend more time in the second and third rocker phases of gait. These variations suggest that foot pronation significantly affects gait biomechanics.

Regarding all other baropodometric variables, both static and dynamic, we can observe that although the results are not statistically significant for most variables, a higher FPI (more pronated foot) corresponds to a greater Fick angle and longer times in each of the gait phases. In terms of stability, children aged 5 to 7 years with a more pronated FPI have less stability, which reverses in children aged 8 to 10 years, who have greater stability. Similarly, in children aged 8 to 10 years with a supinated foot, the gait phases are shorter, and stability worsens.

All these data can be found in

Table 5. Baropodometry variables of the sample by age and FPI in children.

	5 to 7 Years					8 to 10 Years
Baropodometry Variables	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated	Total	FPI Normal (0 to +5)	FPI Supinated (−1 to −12)	FPI Pronated (+5 to +12)	FPI Normal vs. Pronated
	n = 114	n = 74	n = 1	n = 39	p	n = 82	n = 51	n = 2	n = 29	p
Dynamic 2D (°)
Fick Angle R	4.33 ± 5.56	3.58 ± 5.7	N/A	4.3 ± 5.82	0.482	4.42 ± 5.73	4.73 ± 5.93	4.5 ± 1.98	3.89 ± 5.62	0.885
Fick Angle L	3.88 ± 5.72	3.97 ± 4.85	N/A	4.84 ± 6.71	0.554	6.12 ± 5.34	6.44 ± 5.71	7.05 ± 5.59	5.49 ± 4.75	0.869
Min pronation L	−2.96 ± 4.74	−3.08 ± 4.96	N/A	−2.67 ± 4.4	0.439	−3.39 ± 4.89	−3.14 ± 4.61	−12 ± 8.49	−3.24 ± 4.8	0.314
Min supination R	−4.42 ± 5.29	−4.22 ± 4.78	N/A	−4.79 ± 6.25	0.766	−3.85 ± 5.39	−4.16 ± 5.07	−4 ± 8.49	−3.31 ± 5.93	0.657
Max pronation L	10.52 ± 4.58	10.5 ± 4.75	N/A	10.41 ± 4.28	0.845	11.18 ± 5.87	11.66 ± 6	5.5 ± 2.12	10.74 ± 5.67	0.151
Max supination R	9.96 ± 4.9	9.53 ± 4.64	N/A	10.74 ± 5.38	0.027 *	9.95 ± 10.23	10.73 ± 12.15	7 ± 2.83	8.79 ± 5.97	0.409
During Stance Phase of Gait
Forefoot Contact Phase (ms)	38.18 ± 23.95	37.97 ± 25.84	N/A	39.23 ± 20.15	0.348	45.79 ± 23.94	46.84 ± 23.25	35 ± 21.21	44.69 ± 25.79	0.604
Foot Flat Phase (ms)	267.09 ± 92.38	272.5 ± 93.73	N/A	253.41 ± 88.22	0.921	324.7 ± 92.46	328.24 ± 89.87	361.5 ± 44.55	315.93 ± 100.17	0.031 *
Forefoot Push Off Phase (ms)	271.46 ± 108.39	274.38 ± 113.32	N/A	269.1 ± 99.18	0.676	268.3 ± 85.02	270.96 ± 73.46	278 ± 162.63	262.97 ± 101.4	0.006 **
Stabilometric variables (static) (%)
R stabilometric	52.82 ± 4.98	52.57 ± 4.26	N/A	53.21 ± 6.19	0.145	51.24 ± 5.14	51.55 ± 5	49.85 ± 0.92	50.78 ± 5.59	0.707
L stabilometric	47.18 ± 4.98	47.43 ± 4.26	N/A	46.79 ± 6.19	0.112	48.71 ± 5.16	48.37 ± 5.02	50.15 ± 0.92	49.21 ± 5.59	0.694
Forefoot stabilometric	39.51 ± 7.29	39.32 ± 6.94	N/A	40.16 ± 7.86	0.277	42.32 ± 6.88	41.71 ± 7.11	42.35 ± 3.61	43.39 ± 6.65	0.453
Rearfoot stabilometric	60.41 ± 7.32	60.68 ± 6.94	N/A	59.63 ± 7.91	0.473	57.68 ± 6.88	58.29 ± 7.11	57.65 ± 3.61	56.61 ± 6.65	0.453
C1 stabilometric	20.67 ± 4.73	20.55 ± 4.44	N/A	21.03 ± 5.27	0.609	21.7 ± 4.23	21.69 ± 4.22	19.4 ± 4.38	21.88 ± 4.35	0337
C2 stabilometric	18.87 ± 4.37	18.76 ± 4.03	N/A	19.22 ± 4.94	0.153	20.62 ± 4.07	20.02 ± 4.19	22.95 ± 0.78	21.52 ± 3.84	0.136
C3 stabilometric	32.15 ± 5.52	32.01 ± 4.61	N/A	32.19 ± 6.89	0.117	29.71 ± 5.6	29.92 ± 5.89	30.45 ± 5.3	29.28 ± 5.24	0.833
C4 stabilometric	28.31 ± 5.63	28.67 ± 5.43	N/A	27.57 ± 6.06	0.747	28.09 ± 5.53	28.36 ± 5.16	27.2 ± 1.7	27.68 ± 6.35	0.944
Stabilometric variables (gravity center) (mm)
Minimum x-axis L	−0.96 ± 2.55	−0.68 ± 2.46	N/A	−1.49 ± 2.69	0.642	−1.91 ± 3.45	−1.92 ± 3.6	−3.5 ± 0.71	−1.79 ± 3.32	0.893
Minimum y-axis L	61.73 ± 11.48	61.55 ± 10.2	N/A	62.36 ± 13.7	0.526	75.15 ± 12.26	74.82 ± 12	77.5 ± 4.95	75.55 ± 13.25	0.774
Minimum x-axis R	−1.33 ± 3.18	−0.65 ± 2.64	N/A	−2.62 ± 3.75	0.787	−1.24 ± 2.75	−0.86 ± 3.02	−0.5 ± 6.36	−1.97 ± 1.82	0.288
Minimum y-axis R	62.04 ± 11.25	61.55 ± 10.78	N/A	63.15 ± 12.23	0.644	74.91 ± 13.26	73.18 ± 12.46	78.5 ± 9.19	77.72 ± 14.61	0.450
Maximum x-axis L	0.62 ± 2.61	0.69 ± 2.44	N/A	0.51 ± 2.95	0.542	−0.39 ± 3.55	−0.2 ± 3.71	−1.5 ± 0.71	−0.66 ± 3.4	0.803
Maximum y-axis L	71.95 ± 10.89	71.41 ± 9.9	N/A	73.41 ± 12.41	0.384	91.1 ± 65.67	94.88 ± 82.66	84.5 ± 6.36	84.9 ± 14.27	0.851
Maximum x-axis R	0.53 ± 2.91	0.81 ± 2.55	N/A	0.05 ± 3.47	0.549	0.22 ± 3.13	0.71 ± 3.4	1 ± 5.66	−0.69 ± 2.3	0.226
Maximum y-axis R	74.66 ± 12.54	73.38 ± 10.66	N/A	77.38 ± 15.33	0.565	85.37 ± 13.81	83.18 ± 11.9	92 ± 0	88.76 ± 16.59	0.352
Distance traveled L foot	34.73 ± 21.62	34.64 ± 20.3	N/A	35.44 ± 24.21	0.111	27.4 ± 15.75	27.76 ± 17.75	20 ± 5.66	27.28 ± 12.22	0.326
Distance traveled R foot	44.42 ± 32.86	40.84 ± 21.8	N/A	51.67 ± 47.03	0.711	33.17 ± 19.72	31.18 ± 18.17	40.5 ± 34.65	36.17 ± 21.71	0.874
Ellipse area L (mm2)	2.84 ± 5.11	2.5 ± 3.6	N/A	3.54 ± 7.21	0.173	1.87 ± 2.38	2.08 ± 2.73	2 ± 2.83	1.48 ± 1.57	0.549
Ellipse area R (mm2)	5.08 ± 10.59	3.36 ± 4.79	N/A	8.44 ± 16.49	0.835	2.57 ± 3.39	2.39 ± 3.04	2 ± 2.83	2.93 ± 4.03	0.920
Principal axis ellipse L	5.03 ± 3.14	4.84 ± 2.75	N/A	5.44 ± 3.8	0.251	4.11 ± 2.63	3.9 ± 2.33	2.5 ± 0.71	4.59 ± 3.13	0.286
Principal axis ellipse R	6.13 ± 3.67	5.88 ± 3.16	N/A	6.67 ± 4.5	0.926	5.22 ± 3.44	4.82 ± 3.36	6.5 ± 3.54	5.83 ± 3.59	0.206
Second axis ellipse L	0.48 ± 0.72	0.46 ± 0.65	N/A	0.54 ± 0.85	0.862	0.48 ± 0.71	0.57 ± 0.78	0.5 ± 0.71	0.31 ± 0.54	0.329
Second axis ellipse R	0.66 ± 1.07	0.53 ± 0.73	N/A	0.92 ± 1.51	0.773	0.46 ± 0.67	0.49 ± 0.67	0.5 ± 0.71	0.41 ± 0.68	0.507
Stabilometric variables of each foot
Min CoP (°)	−3.29 ± 5.91	−3.93 ± 5.23	N/A	−2.24 ± 6.97	0.645	−3.72 ± 6.25	−4.7 ± 6.2	−0.5 ± 10.18	−2.22 ± 5.97	0.233
Max COP (°)	3.97 ± 6.04	2.8 ± 3.32	N/A	6.13 ± 8.92	0.963	2.85 ± 4.23	2.49 ± 3.85	5.85 ± 8.27	3.27 ± 4.65	0.779
Min distance CoP (mm)	132.6 ± 35.97	132.55 ± 34.75	N/A	132.13 ± 38.93	0.978	140.89 ± 36.1	140.22 ± 39.46	178 ± 43.84	139.52 ± 28.62	0.088
Max distance CoP (mm)	136.84 ± 36.37	136.28 ± 34.41	N/A	137.38 ± 40.6	0.978	144.43 ± 36.8	143.57 ± 40.1	184 ± 48.08	143.21 ± 29.13	0.089

C1 = left forefoot load; C2 = right forefoot load; C3 = left hindfoot load; C4 = right hindfoot load; CoP = centre of pressure; ° = degrees; FPI = Foot Posture Index; L = left; n = number of individuals; N/A = not applicable (with n < 2, descriptive statistics are meaningless); m = metres; mm = millimetres; Max = maximum; Min = minimum; ms = milliseconds; R = right; seg = seconds; ** p < 0.01, * p < 0.05.

.

Fisher’s exact corrections have been checked to see if there are proportionality differences in the sample number between genders and the results show that there are no such proportionality differences. That is, there are no significant differences in the ratio of boys to girls in any age group.

4. Discussion

The purpose of this study was to analyze how foot type influences various physical characteristics (gender, age, and BMI), laxity, strength, motor tests, and different baropodometric variables in children aged 5 to 10 years (categorized by age and FPI).

The main finding of this study reveals a strong correlation between FPI and the RCSP test. These results align with previous studies that correlate FPI with RCSP [26,27]. Previous research [26,28] has found a high correlation between RCSP and calcaneal valgus. This finding is significant as it highlights that RCSP can be used as an effective tool for detecting foot type since it is quicker, easier to use, and more reliable than FPI [20,26]. We can say that RCSP could be a substitute for FPI.

Based on our results, it can be observed that children with a higher FPI (more pronated foot) have a higher RCSP. This result aligns with the main finding of this study (correlation between FPI and RCSP). Thus, we can speculate that by taking a single measurement, it is possible to predict the type of foot a child has, instead of performing the six measurements required for FPI [4].

Our data analysis also found several notable differences in foot dynamics between age groups based on FPI. Children aged 5 to 7 years with a more pronated FPI showed greater maximum supination during gait and increased strength, particularly in plantar flexion. This suggests that children with a tendency towards greater pronation compensate for this excessive pronation with more pronounced supination and increased plantar flexion strength. This behavior could be related to compensatory mechanisms that help stabilize the foot and maintain functional gait, which is crucial for children in this developmental stage as their musculoskeletal system is still maturing [29].

On the other hand, children aged 8 to 10 years with a higher FPI tend to exhibit greater supination and spend more time in the forefoot push-off phase and the flat foot phase. This may indicate that children with a higher FPI tend to keep their foot in the push-off phase longer and spend more time in the second rocker phase during gait. This pattern may be related to the need to adapt foot mechanics to manage increased stiffness or excessive pronation, influencing the time spent in different gait phases [30]. These findings suggest that differences in FPI affect foot dynamics differently across age groups. While younger children with a more pronated FPI may compensate with greater supination and strength, older children with a higher FPI tend to adjust their gait pattern with changes in the duration of the push-off and flat foot phases. Understanding this can be crucial for developing personalized intervention strategies that address the specific needs of each age group.

Regarding the relationship between flat feet and higher BMI, we found similarities [31,32] and discrepancies [13,33] in our results compared to the previous literature. Although our results are not statistically significant, our children with pronated feet tend to have a higher BMI than those with neutral feet. It is important to note that the association between BMI and FPI is unclear, and more studies are showing insufficient evidence to link a higher FPI with increased BMI [13,33,34]. Although the trend observed in our study suggests a possible relationship between flat feet and elevated BMI, the lack of statistical significance and discrepancies with the existing literature highlight the need for further research to clarify this association.

Regarding laxity and strength, we observed that a higher FPI score is associated with a tendency towards greater hyperlaxity in the LL and greater foot strength. Children with pronated feet (higher FPI) tend to have greater joint flexibility and increased strength to stabilize the foot. Greater foot pronation could be associated with stretching and overloading of soft tissues and joints, contributing to increased hyperlaxity [35]. In contrast, children with supinated feet (lower FPI) show less foot strength. A possible explanation for our results could be the proposal by McBride et al. that supinated feet may have a lower impact absorption capacity and functional demand compared to pronated feet, resulting in a lower need for muscular strength to maintain control during gait [36]. These findings suggest that foot biomechanics and functional adaptations vary with alignment type, highlighting the importance of adjusting interventions and evaluations based on the specific foot profile to improve function and prevent future problems.

The absence of significant differences in motor function tests according to the foot type presented by the children is an unexpected finding, as notable variations were anticipated based on foot type. This result suggests that the impact of foot type on motor function may be less pronounced than expected. This could be due to compensatory mechanisms developed by the children, individual variability in motor skills, or the limited sensitivity of the tests used [37]. The lack of significant findings underscores the need to consider other factors affecting motor function and suggests that future studies could explore more specific tests and a more comprehensive approach to better understand the relationship between foot type and motor function.

In the literature, baropodometric analysis in the pediatric population has been under-researched. In our analysis of baropodometric variables, both static and dynamic, we found interesting patterns although not statistically significant for most variables. A higher FPI is associated with an increase in the Fick angle and prolonged times in each gait phase. This finding suggests that more pronated feet may experience greater range of motion and longer times in each gait phase due to necessary adaptations to control pronation [38]. In terms of stability, we observed that children aged 5 to 7 years with more pronated feet have less stability, reflecting the difficulty in maintaining balance in a more pronated posture. However, this trend reverses in children aged 8 to 10 years with greater pronation, who show greater stability. This could indicate that, over time, children develop compensatory skills that improve their stability despite continued pronation. Conversely, in children aged 8 to 10 years with supinated feet, the gait phases are shorter, and stability decreases. This may suggest that increased foot supination leads to less efficient weight distribution and a more rigid gait pattern, negatively affecting stability. Following the line of other published articles [39,40], although the results are not statistically significant, the observed patterns suggest that foot type (pronated or supinated) and age can influence gait dynamics and stability.

Finally, our study found a prevalence of FF of 29.9%, using a cut-off point of 6 in the RCSP [20]. This finding reveals that although flat feet tend to correct with age, there is still a significant proportion of children aged 7 to 10 years with this condition. This situation is concerning because if flat feet are not properly treated during childhood, it could lead to a series of orthopedic and functional problems in adulthood [41,42]. It is important to address this issue, as it is known that untreated flat feet can result in problems such as foot pain, malformations in other parts of the body, and gait alterations that can affect quality of life over time [43]. The persistence of a considerable percentage of children with flat feet suggests that current strategies for preventing and treating flat feet may not be sufficiently effective. This result highlights a deficiency in current prevention and treatment methods for flat feet. Despite advances in detection and diagnosis, it seems that enough measures have not yet been implemented to reduce the prevalence of this condition in the pediatric population. It is essential to develop and implement more effective strategies to prevent and treat flat feet from an early age to minimize its potential long-term negative effects and improve the health and well-being of affected children. Lastly, we can observe that in our study the sample of supinated FPI is very small, this is in line with the literature [4,5,13], which informs us that cavus foot or supinated feet are the least common feet. Even so, these data should not be underestimated, as the supinated foot or cavus foot requires the same attention and analysis as the pronated foot or flat foot, mainly because the supinated foot does not change over time [13].

4.1. Limitation and Strengths of the Study

This study has several limitations that need to be mentioned. First, the age of the participants, which only included children aged 5 to 10 years, excluding those up to 14 years old when foot bone development is complete. Additionally, it should be noted that there was a small number of 10-year-old participants. The reason for this age range was that in Spain, children transition from primary education to secondary school during this stage, and this study was conducted in a school, so we could not access older children. Furthermore, our study was based on the observation of a large, multicentric, and homogeneous sample, although limited to a single country, with the participants’ ethnicity being primarily Caucasian, which prevents extrapolation of the results to other ethnicities. Moreover, although the RSscan Footscan^® 9 (RSscan International, Olen, Belgium) pressure platform has demonstrated good intra-evaluator and inter-evaluator reliability [25], it only measures forces perpendicular to the ground, without considering forces in other planes. Finally, the fact that the children felt observed while walking could have altered their usual gait patterns. Lastly, another limitation is the low number of children with supine FPI. This meant that no significant differences or associations could be detected. Even so, these data should not be underestimated, as it may be overlooked in larger studies because it is not as common.

Despite the limitations, this study also has significant strengths. Firstly, the evaluation of plantar pressure during dynamic movements has been established as a reliable method for analyzing foot structure and function. Secondly, it covered a broad spectrum of ages in children. Thirdly, the measurement instruments used are commonly employed in both clinical practice and research. Additionally, the data obtained and our conclusions may have significant implications for both clinical practice and public health. Finally, and to our knowledge, no studies have linked FPI with as many variables as the present study, making this the first study to analyze numerous morphofunctional variables in this population and link them with foot type.

4.2. Relevance to Clinical Practice

The main clinical implication derived from this study is the potential to replace FPI, which focuses on the three-dimensional evaluation of the foot rather than just gait patterns, with RCSP as a tool for assessing foot type. This allows for the incorporation of this simple tool into public health settings and its use as part of basic triage for evaluating pediatric feet. These results are in line with the studies of Cho et al. [26] and Martinez-Sebastian et al. [44]. They point out that the RCSP is a simple, accessible, and quick screening test mainly for paediatric flatfoot. This makes the RCSP particularly valuable for health professionals who do not have a specialization in podiatry or pediatric gait, using it as a substitute for FPI.

It should be noted that although the number of children with pronated feet decreases with age, in the 8–10-year age group (when the internal longitudinal arch should almost be formed) we found 29 children with pronated FPI out of a total of 82 children. This figure is very high and worrying, because although there is still a lot of confusion about whether or not flat feet need to be treated [41], we found several studies that tell us that if flat feet are left untreated in the long run, they could cause problems [45]. It is also known that the sooner this flatfoot is treated, the more likely we are to find success in the treatment and remission of this condition [46]. Thus, these results should alarm us and we should try to screen before children have completed their development and it is too late to intervene.

Further research is needed to better understand the complex relationships between foot structure and child development, and also to provide a solid foundation for future research and clinical practices. The information obtained can guide health professionals, educators, and parents in the early detection of problems and the implementation of strategies to promote healthy and balanced development during the formative years. This knowledge can contribute to improving evaluation and treatment approaches and designing intervention programs that support optimal motor development and the overall well-being of children during their growth years. Future research of this kind, including equally large samples and a broader age range (encompassing various ethnic groups and geographic regions), could provide greater precision in understanding the influence of foot type and associated characteristics during childhood and adolescence, thereby improving our understanding of foot development throughout growth.

5. Conclusions

This study demonstrates that foot type significantly influences various physical characteristics (such as gender, age, and BMI), laxity, strength, motor tests, and baropodometric variables in children aged 5–10 years. Significant differences between age and gender groups are observed, highlighting the need for personalized assessment and management of foot-related conditions at this stage of development. In addition, the RCSP is presented as a useful tool for health professionals without podiatric specialization, allowing efficient assessment as a surrogate for the FPI in pediatric clinical settings.