Intellectual and developmental disability (IDD) is defined as a developmental disorder characterized by limitations in intellectual functioning and adaptive behavior, with an impact on conceptual, practical and social domains (Schalock et al., 2021). IDD manifests itself by the age of 22 and can vary in severity from mild to profound (Schalock et al., 2021). In addition, people with IDD tend to have difficulties in executive functioning (Rodrigues et al., 2019) and motor performance, namely mobility limitations (Cleaver et al., 2009) resulting from lower tonic and muscular performance, associated with sensory deficits and slower and more imprecise motor responses (Carmeli et al., 2008), which compromise their autonomy in activities of daily living and social participation (Enkelaar et al., 2013).

At the same time, there is a high prevalence of comorbidities such as overweight/obesity, type II diabetes, hypertension and cardiovascular diseases (Calders et al., 2011; O’Leary et al., 2018), resulting from risk behaviors such as a sedentary lifestyle (Bergström et al., 2013; O’Leary et al., 2018) and reduced physical activity (PA) (Bossink et al., 2017; Pierce and Maher, 2020). These behaviors contribute to low levels of physical fitness, namely reduced levels of strength, aerobic capacity, balance and flexibility (Wouters et al., 2017) with negative consequences for walking (Cleaver et al., 2009), postural control (Lahtinen et al., 2007), manipulation of objects (Enkelaar et al., 2013) and consequently success in performing activities of daily living (Oppewal et al., 2014). This decrease in muscle strength, especially in the lower limbs, is closely associated with a decline in physical and functional capacity (Mendonca et al., 2013).

Scientific evidence has highlighted the benefits of PA and physical exercise (PE) in the prevention and control of various chronic diseases (Calders et al., 2011), as well as in improving physical fitness, namely improvements in lower limb strength, cardiorespiratory fitness (Diz et al., 2021; Jacinto et al., 2023a; Jacinto et al., 2023b; Obrusnikova et al., 2021) and body composition, decreasing fat mass and increasing muscle mass (Jacinto et al., 2023a; Obrusnikova et al., 2021). Even though research into the practice of sports in this population is limited (Diz et al., 2024b), studies carried out with other populations (e.g., elderly; visually impaired) show similar benefits (Pedersen et al., 2017).

The low adherence of people with IDD to PA and PE programs is partly a consequence of the scarcity of programs adapted to the needs and interests of this population, as well as the absence of structured progression in activities (Obrusnikova et al., 2022) and the lack of guidance from qualified professionals with experience in the field (Jacinto et al., 2021a). In addition, the shortage of motivation for regular practice is also a major obstacle (Bossink et al., 2017), highlighting the need for more participant-centered approaches. The short duration of intervention programs and their discontinuity are also identified as barriers to participation and the effectiveness of interventions (Burns et al., 2024), which can compromise participants’ motivation and involvement. Scientific evidence suggests that longer-lasting and more structured interventions tend to promote greater adherence and be more successful (Burns et al., 2024). Additionally, participation in programs that include diverse components, such as games, can encourage the frequency of practice and physical fitness (Farías-Valenzuela et al., 2022). In the same way, programs that involve social involvement (peers and teams) are often more motivating and facilitate practice (Bossink et al., 2017; Jacinto et al., 2021b) also, participants who engaged in team sports reported higher satisfaction with their lives and greater appreciation of their living conditions (Moltó and Bruna, 2017). PA and PE programs have proven to be less motivating and interesting for people with IDD (Jacinto et al., 2023a; Jacinto et al., 2024). In this regard, and considering the points discussed above, exploring the practice of sports proved to be relevant.

Sports-based intervention programs that is structured, adapted to the characteristics and interests of the participants, respecting their needs, prioritizing progression that is in line with the participants abilities and led by professionals with specialized training and experience in the field of disability. This program seeks to respond to the barriers already identified, being a long-term program that prioritizes the participants’ preferences and needs, including their opinion on the sessions, with the aim of maintaining motivation and involvement over time.

The aim of this study is to evaluate the effect of a programs e based on the practice of sports (basketball, football, volleyball, and handball) once a week for 36 weeks on the body composition and functional physical fitness of people with IDD. Thus, the authors intend to verify the following hypotheses: (i) regular practice of sports improves body composition and physical fitness in people with IDD; (ii) these improvements are greater in the EG compared with the CG.

Table 3 shows the comparison between the CG and the EG at the pre-intervention moment. As can be seen, in the initial assessment, there are no statistically significant differences between the two groups.

Table 4 shows the comparison between the CG and the EG at the post-intervention moment. Analyzing it, it is possible to verify that in the post-intervention period, as happened in the pre-intervention period, there were no statistically significant differences in the comparison between the two groups.

The comparison between the pre-intervention (moment 0) and the post-intervention (moment 1) for the EG can be analyzed in Table 5.

When comparing the pre-intervention moment with the post-intervention moment in the EG, it is possible to verify that it presents significant improvements in the variables muscle mass (p < 0.01; r = 0.301), sit and stand test (p = 0.01; r = 0.324) and 6 min walk (p < 0.01; r = 0.399), all with a medium effect size. In the BMI variable, a significant difference is also noticeable (p = 0.01; r = 0.301), with a medium effect size, indicating that the variable under study did not undergo a positive change.

Table 6 represents the comparison between the pre-intervention (moment 0) and the post-intervention (moment 1) for the CG.

As can be seen in the table mentioned, when comparing the pre-intervention and post-intervention moments for the CG, statistically significant differences were observed in the handgrip test on the right hand (p = 0.02; r = 0.458), with a medium effect size, suggesting a decrease in performance.

Although the differences are not statistically significant, the comparison between the two moments reveals an increase in the median of the sit and stand test, suggesting a decrease in test performance. Similarly, it is possible to verify an increase in the median for the BMI and fat mass variables of body composition.

All GE participants evaluated the sessions, considering their level of satisfaction, and 94% of participants expressed high satisfaction with the sessions, 4% gave an intermediate evaluation and only 2% indicated that they did not enjoy the sessions.

The main aim of this study was to analyze the effect of a 36-week sports-based program on the body composition and functional fitness of people with IDD.

Considering the results obtained, when comparing the EG and CG at the post-intervention moment, no statistically significant differences were found between the groups. However, when comparing the pre- and post-intervention moments (moment 0 and moment 1) in the EG, it was possible to see that the participants showed significant improvements in the BMI and muscle mass variables relating to body composition and in the sit and stand and 6-min walk tests relating to functional physical fitness. Regarding the CG, there was a statistically significant difference in the comparison between the two moments (moment 0 and moment 1), specifically in the handgrip test, with the right hand showing a decrease in values.

These results seem to confirm the hypotheses initially established, showing that: (i) the sports participation improves body composition and physical fitness in people with IDD and (ii) these improvements are greater in the EG compared with the CG.

With regard to the body composition of the participants in the EG, it is possible to see a significant increase in muscle mass and a significant increase in BMI when comparing the time points, however, although the value is not significant, it is also possible to see a decrease in the participants’ fat mass. BMI is calculated using the formula weight divided by height squared, and can increase due to high amounts of muscle mass and/or fat mass. Therefore, an individual with high muscle mass can have a high BMI, even if their body fat is not excessive (Rezende et al., 2010). Thus, the values obtained seem to indicate that the increase in BMI can be justified by the increase in muscle mass, considering that it has increased, it is normal that the participants’ weight has also increased and, consequently, their BMI, despite the slight decrease in fat mass values.

One possible explanation for the lack of a statistically significant difference in the fat mass variable, which is part of body composition, could be related to the fact that variables such as diet were not controlled. Considering that previous studies report that the average calorific ingestion tends to be higher in the IDD population, this is a factor that could be considered relevant (Hoey et al., 2017).

The result achieved for the muscle mass variable seems to be corroborated by the study carried out by Tomé et al. (2024), where the authors found a statistically significant improvement in the muscle mass (p = 0.05) of the participants. The authors applied a physical exercise intervention program, using recreational games from team sports, once a week and lasting 60–90 min, to adults with IDD. Considering the type of intervention and the sample of the study carried out by Tomé et al. (2024), the results they obtained are of particular interest.

The statistically significant difference in the sit and stand test between moment 0 and moment 1 for the EG suggests that the intervention program contributed to an increase in lower limb strength and endurance. This result can be explained by the exercises carried out during the sessions, namely exercises that involve constant movement, rapid changes of direction and lower limb thrusting, as is the case with various exercises carried out in football, basketball, handball and volleyball. The results obtained are in line with those of the study carried out by Wang et al. (2022), in which the authors implemented a physical activity intervention program for 12 weeks, twice a week, using different aerobic games for children with IDD and found significant improvements in the sit and stand test (p = 0.001). The same occurred in the study carried out by Calders et al. (2011), where the authors found statistically significant differences in the strength and endurance of the lower limbs, using the sit and stand test (p = 0.03) after a combined intervention program of strength training and aerobic training, lasting 20 weeks, twice a week, in adults with IDD. In addition, Pedersen et al. (2017), when carrying out an intervention program based on team sports with an elderly population, found statistically significant differences in the sit and stand test (p < 0.05), suggesting that it contributed to improving the strength and endurance of the lower limbs.

Our results in the 6-min walk test also showed a statistically significant difference when comparing the two moments in the EG, suggesting that the intervention program contributed to improving the participants’ cardiorespiratory capacity. These results are in line with those presented by Wang et al. (2022), in which the authors found statistically significant improvements in the 6-min walk test, with an increase in the distance covered by children with IDD, after the implementation of a 24-session intervention program, carried out twice a week, using aerobic games (Wang et al., 2022). Also, in the study carried out by Diz et al. (2021) with adults with DID, the participants in the EG showed a statistically significant improvement in cardiorespiratory capacity after implementing a 12-week, twice-weekly adapted physical activity program. The same occurred in the study by Obrusnikova et al. (2021), where the authors evaluated the effect of a multicomponent resistance training intervention on the strength and functional performance of adults with IDD, and found a statistically significant improvement in the 6-min walk test (p < 0.05), suggesting an increase in cardiorespiratory capacity. Also, in the study by Kocić et al. (2017), the authors found that the EG showed a 10% increase in the distance covered in the 6-min walk test (p < 0.05), after the implementation of an adapted basketball intervention program in adolescents with IDD, lasting 8 weeks and 4 times a week.

As mentioned in the previous paragraph, the difference seen in the 6-min walk test seems to indicate that the intervention program contributed to an increase in the participants’ cardiorespiratory capacity. These results may be related to the fact that the participants tended to lead sedentary lifestyles, and that regular sports practice was included in their routine, since there is a continuous stimulus for developing this capacity. In addition, team sports, such as those practiced during the sessions, involve constant movement, changes of direction and moments of running, which promote cardiovascular and respiratory adaptations (Yue and Hong, 2023). It should also be noted that, as we have already seen, there was an improvement in the strength and endurance of the lower limbs, which may have contributed to the participants being able to cover a greater number of meters more efficiently and with less fatigue in the lower limbs.

This set of abilities, related to lower limb strength and endurance, as well as cardiorespiratory capacity, tends to contribute to daily functional performance, with positive repercussions on activities of daily living, sitting down and standing up from chairs, going up and down stairs, and reducing the risk of falls (Aslan et al., 2025; Calders et al., 2011; Delgado-Lobete et al., 2021; Obrusnikova et al., 2021).

Regarding the CG, it was possible to see a statistically significant difference when comparing the two moments in the handgrip test for the right hand. Since the CG participants maintained their usual daily activities, the reason for this difference is not obvious. However, we can say that the intervention program seems to have contributed to maintaining strength in the upper limbs of the EG, as there were no significant changes in the handgrip tests, unlike the CG.

One possible explanation for the lack of significant differences in the other physical fitness variables in the EG may be related to the weekly frequency of the sessions. Although one session a week is beneficial and has brought benefits in several of the variables under study, it may not have been enough to promote improvements in upper limb strength and agility, balance and speed. Although some of the sports worked on during the sessions included the use of the upper limbs (e.g., throwing in handball or basketball), the intensity, frequency and specificity of the stimulus may not have been sufficient to bring about measurable gains in handgrip strength. Increasing the weekly frequency could lead to improvements in these variables.

Despite the obvious difficulties in executing exercises orientated toward gripping balls, dribbling and throwing, it is worth highlighting the improvements seen over the course of the sessions, where a more efficient grip was visible, as well as more precise and controlled throws. Despite the limitations, these improvements were also seen in exercises where ball handling with the feet was prioritized, as in the case of football. Even though they are not quantifiable improvements, it is pertinent to mention them, especially as they are related to exercises that require the simultaneous performance of two or more tasks and this is a difficulty experienced by this population (Jankowicz-Szymanska et al., 2012; Martin et al., 2010).

As well as analyzing the effect of sports on the body composition and physical fitness of adults with IDD, the intervention program had the additional objectives of mitigating barriers to the practice of PA, PE and sports, as well as valuing the preferences and needs of the participants, including their opinion of the sessions. In this context, the evaluation of participant satisfaction revealed extremely positive feedback on the sessions (94.10%), suggesting that the intervention contributed to the motivation and ongoing involvement of the participants. This can be supported by the absence of dropouts attributed to the program itself, contrary to evidence presented by other studies, which report the low participation of people with IDD in PA and PE intervention programs (Gjestvang et al., 2020). Monitoring participants’ satisfaction allows PE technicians to understand which exercises, activities, games and modalities participants enjoy the most, analyze the sessions based on this feedback and make the necessary adjustments. These adjustments should preserve the fundamental components to be developed but seek to align with the interests and preferences of the participants, promoting their inclusion, active listening and motivation.

The high level of adherence to the program and the results achieved reinforce the importance of integrating this type of intervention into institutional and community contexts. It is therefore essential that exercise instructors, institutions and local authorities actively contribute to its implementation and, just as importantly, to its continuity over time.

In short, the results obtained suggest that the intervention program, based on the practice of sports, contributed to an improvement in the variables of muscle mass, strength and endurance of the lower limbs and cardiorespiratory capacity.

The 36-week weekly intervention showed statistically significant improvements in body composition, particularly muscle mass, as well as lower limb strength and endurance, cardiorespiratory capacity and functional physical fitness. These results are particularly relevant considering the motor and functional difficulties often associated with this population, thus reinforcing the role of sports as an asset for promoting health, physical fitness and quality of life.

The evaluation of the participants’ satisfaction indicated that the vast majority of the sessions were enjoyed, a factor that may have contributed to their increased motivation and, consequently, to the low drop-out rate. It should be noted that none of the participants left the intervention for reasons related to the program.

The results achieved and adherence to the program support the importance of including this type of intervention in institutional and community contexts. In this sense, it is important that PE technicians, institutions and local authorities reflect on the importance of these programs, recognize their value and contribute to their development.

In short, this study aims to contribute to the advancement of knowledge in the field of sports science by demonstrating that structured sports programs, implemented on a regular basis, with a focus on the individual, can bring benefits in terms of body composition and functional physical fitness for people with IDD, paving the way for future research and the implementation of more inclusive and effective policies.