Author(s): KLAVINA, A., STRAZDINA, N., GALEJA, Z. , Institution: LATVIAN ACADEMY OF SPORT EDUCATION, Country: LATVIA, Abstract-ID: 599

INTRODUCTION:
Physical fitness is an important marker of health in adolescents; however, youth with intellectual disability (ID) are often described as a homogeneous group with low fitness. Evidence on fitness profiles, interrelationships among fitness components, and within-group heterogeneity in adolescents with ID remains limited. Identifying fitness-based phenotypes independent of disability status may support individually tailored exercise interventions
METHODS:
This study involved 165 adolescents aged 12–18 years (94 with moderate ID and 71 typically developing) from seven educational institutions. The Eurofit physical fitness battery was used to obtained fitness scores. Composite z-scores were calculated for combined strength, combined speed, and local muscular endurance, as well as an overall fitness score. Group differences and associations among fitness components were examined using ANOVA, correlation, and regression analyses. In addition, hierarchical cluster analysis (Ward’s method, squared Euclidean distance) followed by k-means clustering was performed to identify fitness phenotypes independent of disability status.
RESULTS:
Adolescents with ID demonstrated significantly lower performance than typically developing peers in dynamic and speed-based tasks (p < .001–.005), while no significant group differences were observed for flexibility, handgrip strength, static balance, or bent-arm hang performance in girls. Age was strongly associated with cardiorespiratory endurance and combined strength in boys from both groups. Combined strength emerged as the strongest predictor of overall fitness in adolescents with and without ID. Cluster analysis identified three distinct fitness phenotypes: a low-fitness cluster (n = 90), a moderate profile characterised by higher strength and speed but lower endurance (n = 46), and a high-fitness cluster (n = 29). Large between-cluster differences were observed across all fitness components (η² = 0.33–0.68; p < .001). Although cluster membership was associated with disability status (p < .001), adolescents with ID were represented across all clusters.
CONCLUSION:
Adolescents exhibit distinct fitness profiles that are not fully explained by disability status. These findings highlight substantial within-group heterogeneity and support fitness-based profiling to develop individually targeted exercise interventions for both adolescents with ID and typically developing peers.

The study was financed by “Innovations, methodologies and recommendations for the development and management of the sports sector in Latvia” (Nr.VPP-IZM-Sports-2023/1-0001)