Exploring Energetic and Anthropometric Determinants of Front Crawl Technique in Young Swimmers Using IMU Sensors: A Preliminary Study

The study investigated how hand movement patterns affect overall kinematic indicators of front-crawl sprint technique in boys aged 12–14, while considering the influence of the morpho-functional profile. The sample consisted of 47 participants. Data were collected from anthropometric measurements (8 variables), a 20-s arm-cranking test (6 variables), and a 25-m front crawl trial. Swimming motion was characterized using IMU sensors (BlueTrident) and Artificial Intelligence (8 variables). Video analysis was used to determine swimming velocity (v), stroke rate (SR), stroke length (SL), and stroke index (SI). PCA analysis identified five components: Large Body Size (LBS), Low Fat (LF), Enormous Power (EP), Dynamism (D), and High Angular Velocity (HAV). Pearson correlation analysis revealed strong associations between LBS and EP (r = 0.85), as well as between D and EP (r = 0.51) and D and LBS (r = 0.34). Velocity was related to LBS, EP, D, and LF (r = 0.38–0.56). SR showed strong associations with D (r = 0.76) and EP (r = 0.35), whereas SL was negatively associated with D (r = − 0.44). SI was related to LBS, LF, and EP (r = 0.38–0.49). Overall kinematic indicators are influenced by hand acceleration and angular velocity, and IMU-based technique assessment supports evaluation of how effectively young swimmers utilize their anthropometric–energetic potential.