Gender Inequality and Sex Differences in 20 Meter Shuttle Run Test Performance across 45 Countries

PURPOSE: To determine if within-country sex differences in 20-meter shuttle run test (20mSRT) performance are related to global gender inequality indices. METHODS: A systematic review was carried out to identify studies that reported 20mSRT descriptive data on apparently healthy children and youth aged 9 to 17 years. Descriptive data were standardized to running speed (km/h) at the last completed stage. Within-country 20mSRT performance for girls and boys were calculated as population-weighted mean z-scores relative to children of the same age from all countries. Within-country population-weighted mean z-scores for girls and boys were subtracted to represent the mean z-score sex difference in 20mSRT performance for each country, described as Zdiff. Five gender inequality indices were identified as potentially relevant in describing sex differences in 20mSRT performance across countries (i.e., Gender Equity Index, Gender Empowerment Measure, Global Gender Gap Index, Gender Inequality Index, and Social Institutions and Gender Index). Pearson’s correlations were calculated to describe the associations between Zdiff and indices of gender inequality. RESULTS: Sex-specific z-scores were calculated from 1,141,514 children and youth (48% female). Within-country 20mSRT performance of girls and boys were very strongly correlated (r=0.92; 95%CI: 0.87, 0.96).The sex differences in performance (Zdiff) were calculated for 45 countries representing five continents. The mean Zdiff was 0.04 ± 0.23 with values ranging from -0.48 (girls had a better 20mSRT mean z-score relative to boys) to 0.67 (boys had a better 20mSRT mean z-score relative to girls) standardized units across the 45 country sample. Zdiff across countries were moderately and negatively correlated with the Global Gender Gap index (r=-0.42; 95%CI: -0.65, -0.12). Correlations across all other indices were of low-to-moderate strength, ranging from r=-0.23 (95%CI: -0.46, 0.11) to r=0.25 (95%CI: -0.05, 0.52). CONCLUSIONS: Although various indices measure gender inequality, it appears that the underlying constructs of these indices vary substantially. Furthermore, gender inequality does not fully explain sex differences in 20mSRT performance, and other broad country-level aspects may better explain the differences between boys and girls.