Gender Differences, Motor Skills and Physical Fitness Heterogeneity in Adults with Down's Syndrome

Abstract

Background-Adults with Down's syndrome (DS) present lower physical fitness associated with heightened sedentary behaviors and motor skills impairments. Their etiologies and determinants seem to be heterogeneous. This study aims to evaluate physical fitness in adults with DS and to identify specific physical fitness profiles depending on gender and physical activity levels. Methods-Forty adults with DS (16 women, 24 men, 29.7 ± 7.5 years) performed six tests from the EUROFIT Battery and Motor Assessment Battery for Children (MAB-C). Their maximal aerobic capacity was assessed using an incremental treadmill test to assess (VO_2peak). Ecological, physical activity, and sedentary levels were evaluated subjectively (Global Physical Activity Questionnaire) and objectively using an Actigraph GT9X^® accelerometer over a seven-day period. Results-VO_2peak and isometric strength were significantly lower for women (p < 0.01), whereas men had significantly lower flexibility than women (p < 0.05). Using a principal component analysis and an agglomerative hierarchical analysis, we identified three clusters. Cluster 1 (n = 14; 50% men; Body Mass index = 28.3 ± 4.3) was characterized by significantly poorer physical fitness variables (VO_2peak (p < 0.01), strength (p < 0.01) and balance (p < 0.05)) compared to Clusters 2 and 3. Cluster 2 (n = 19; 58% men; Body Mass index = 22.9 ± 2.0) and Cluster 3 (n = 19; 58% men; BMI = 22.9 ± 1.9) were characterized by subjects with comparable physical fitness profiles, except for the balance capacities, which were significantly lower in Cluster 3 (p < 0.05). Conclusions-DS subjects exhibited high heterogeneity in terms of physical fitness, PA, and sedentary levels, with a significant gender effect. The present findings are important to identify subjects at higher risk of sedentary behaviors and impaired motor capacities to develop personalized PA programs.

Keywords: Down’s syndrome; cluster analysis; motor skills; physical activity; physical fitness.

Figure 1

Principal component analysis biplot. Participants with DS are represented from 1 to 24 for men and 25 to 40 for women. Each point represents a subject and the color its membership in the cluster. On this graph, two diametrically opposed vectors are negatively correlated, two vectors forming an acute angle are positively correlated, two vectors forming a 90° angle are independent of each other. The greater the distance between the vectors, the closer their relationship is to the significant threshold. A subject near a vector reveals a high score for this variable, a subject diametrically opposed to a vector reveals a low score for this value. A: gender, B: VO_2peak, C: Flexibility, D: isometric strength, E: explosive strength, F: dynamic balance, G: BMI, H: static balance factor.

Figure 2

Factor map obtained by agglomerative hierarchical cluster analysis. Cluster 1 (orange) included 7 males and 7 females with the highest age and BMI and the lowest physical fitness and physical activity level. They were characterized by an effort limitation (%VO_2predicted < 77%); Cluster 2 (blue, 12 males and 7 females) and Cluster 3 (red, 5 males and 2 females) were characterized by normal BMI and very good VO_2peak values. Participants in Cluster 2 had the highest static and dynamic balance score. Participants in Cluster 3 had the highest flexibility, explosive and isometric strength.