Isometric Strength, Joint Mobility, and Muscle Strength Ratios Among Female Artistic Swimmers from the Spanish National Artistic Swimming Team: A Cross-Sectional Study Across Age Categories

Background and Objectives: Artistic swimming demands high levels of strength, joint mobility, and body control; however, the physical profiles of elite athletes in this sport remain insufficiently characterized. This study aimed to characterize and compare isometric strength, joint mobility, inter-limb differences, and muscle strength ratios across the Youth, Junior, and Senior age categories of the Spanish National Artistic Swimming Team. Methods: This cross-sectional observational study included 36 elite female artistic swimmers, defined by their selection for the Spanish National Artistic Swimming Team: 11 Youth, 12 Junior, and 13 Senior athletes. Anthropometric characteristics, shoulder and hip ranges of motion assessed using photographic goniometry, upper- and lower-limb isometric strength, handgrip strength, and countermovement jump height were evaluated. Age categories were compared using the Kruskal–Wallis test, followed by Dunn’s post hoc comparisons with Holm correction. Inter-limb differences were analyzed using the Wilcoxon test. Results: Senior athletes generally exhibited greater isometric strength than younger age categories. Among the main between-category differences, Senior athletes showed greater normalized shoulder internal-rotation strength than Youth athletes (1.56 vs. 0.95 N/kg; group-specific 95% CIs around the means: 1.43–1.69 and 0.80–1.11, respectively) and greater hip-abduction strength (2.34 vs. 1.71 N/kg; group-specific 95% CIs around the means: 2.07–2.60 and 1.51–1.93, respectively). The corresponding omnibus Kruskal–Wallis effect sizes were η2 = 0.40 and η2 = 0.32, respectively. Differences were observed in CMJ height and absolute right handgrip strength. No significant differences were observed after normalizing handgrip strength to body mass. Between-category differences were observed in certain measures of hip mobility but not in shoulder mobility. Inter-limb differences were limited to specific variables. Conclusions: These findings provide a preliminary descriptive characterization of elite female artistic swimmers and reveal differences between age categories, primarily in specific strength variables. These cross-sectional differences between age categories should not be interpreted as evidence of developmental adaptations or training-induced changes. Given the cross-sectional design and small group sizes, the application of these findings to athlete monitoring, training, or the interpretation of inter-limb differences requires confirmation in longitudinal studies.