Problems with postural control cause difficulties in children's motor development, leading to significant structural and functional complications, including pelvic obliquity, scoliosis, and asymmetries in both active and passive ranges of motion. All these difficulties affecting posture control have a negative impact on children's functional autonomy and independent participation in their daily activities, as well as on their interaction with different environments, mainly family, social, and educational. In view of this situation, the 3D Adaptive Sitting System "SSAP3D", a 3D pelvic ser with a self-extracting abductor cushion, is proposed as an alternative.

The main objective is to develop and test a novel 3D-printed adaptive seating system, called SSAP3D, tailored to individual needs of children with Neuromotor Dysfunction, to assess whether it promotes the functional performance of children in their daily and meaningful activities.

A secondary objective is to analyze whether the use of SSAP3D promotes the children's participation in different environments compared to a conventional seated system.

The sample is estimated at 12 children, all of them were between 2-6 years old and with Neuromotor Dysfunction from early attention centers, as well as from private rehabilitation centers or associations.

The intervention program will be the same for each participant, but in different temporal order. 6 children will use during the first 6 weeks the 3D seat and the following 6 weeks their usual seating system; the others 6 children inverted order. The 3D seat will be made individually for each child. The device will be delivered 3 weeks after the scanning-data collection accompanied by guidelines for use. There will be 2 online follow-up sessions.

Hypothesis: the implementation of the SSAP3D allows to ensure the postural requirements of children with Neuromotor Dysfunction and to favor their functional performance in daily and meaningful activities at home, at school and in their community. In addition, it will have a positive impact on the quality of life perceived by the families related to the characteristics of the seat.

This project employs a pilot study of a crossover clinical trial with two groups with two deferent sequences: group 1 will perform the intervention following the sequence SSAP3D + conventional system and group 2 will perform the intervention with the opposite sequence, conventional system + SSAP3D.

Intervention Protocol:

At the beginning of the study, both groups will carry out a 30-minute evaluation session for taking body measurements and collecting data through the scanning of the participant.

Through these measures, the investigators will design a SSAP3D for the participant, an individual 3D printed seat. Three weeks after the data collection session, the SSAP3D will be delivered to the family with a basic guideline on the correct use of the seat.

The intervention, which consist in the use of the SSAP3D during the whole day by the child and the family for 6 weeks, will be controlled by two online follow-up sessions with the family.

Quantitative Data Collection Protocol:

The quantitative assessment will be carried out by two physiotherapists previously trained in the selected measurement tools and with extensive clinical experience in the field of neurorehabilitation. There will be an evaluation site, located at the facilities of the "Asociacion para la Investigación en Discapacidad Motriz" (AIDIMO), in Zaragoza. The evaluations will last approximately 90 minutes. The study will have 4 evaluation times: E1: assessment prior to the start of the study; E2: post-intervention assessment (SSAP3D in the case of group 1 and usual seated system in the case of group 2); E3: post-intervention assessment (usual seated system in the case of group 1 and SSAP3D in the case of group 2); ES1: follow-up assessment 3 months after the end of the study. Outcome measurement tolls 2 and 2 will be videotaped with audio for better analysis by the evaluators, and, in case of any doubt, to be able of consult this material to corroborate the results.

Data Analysis Approach:

Quantitative data will be analyzed using the statical program IBM SPSS Statics Version 29.0 (SPSS Inc., Chicago, Illinois, USA). The normality of distribution of quantitative variables will be verified using the Shapiro-Wilk test, which is suitable for small samples and provides an accurate assessment of normality, Descriptive statics will be presented as mean ± standard deviation or median [interquartile range] for continuous parameters, and as frequency (%) for categorical data. Baseline measurements will be compared between groups using Student's t-test for independent samples, the Mann-Whitney U test, and the chi-square test, as appropriate for the nature of the variable. An intergroup (between groups) and intragroup (within each group) analysis will be performed using a mixed model analysis of variance (ANOVA) one-way and for repeated measures with Bonferroni pairwise post hoc comparisons that adjusts the significance level for multiple comparisons. In case the distribution is not normal. A nonparametric analysis will be performed using the Mann-Whitney U test to compare at the intergroup level and Friedman's test with Tukey's post hoc test to identify differences at the intragroup level. In addition, effect size will be calculated using Cohen's d coefficient, which is interpreted as small (d=0.2), medium (d=0.5) or large (d>0.8). The significance level will be set at p<0.05.

Inclusion Criteria:

• Medical Situation of Neuromotor Disfunction
• Be user of some type of adapted seating system
• Age between 2-6 years
• Have head control levels of 3 to 8 on the Level of Sitting Scale (LSS)
• Be able to maintain a standing position for at least 10 seconds, with or without external assistance.

Exclusion Criteria:

• Presenting moderate or severe cognitive impairment, which generates significant difficulties in understanding the instructions given by the evaluator
• Having suffered a traumatic injury o surgical process in the 6 months prior to the start of the study or during the study