Investigating of the Key Influencing Factors of Pre-Jump Height in Juvenile Trampoline Gymnasts Using Gray Relational Analysis

Hui Wang¹Su Zhang²Hanya Dai¹Mingxin Gong¹Ningxiang Zou¹Lejun Wang^1*

• ¹Tongji University, Shanghai, China
• ²Memorial Hall of the First CPC National Congress, Shanghai, China

Objective: Achieving greater pre-jump elevation has been shown to be essential for trampoline gymnasts to attain high-level competition performance. This study aimed to explore the key influencing factors of the pre-jump height in juvenile trampoline gymnasts, and thus to provide a rationale for training and talent selection of trampoline athletes. Methods: A mixed-methods approach was adopted. First, a comprehensive literature review, expert interviews, and theoretical analysis were conducted to establish preliminary indicators potentially influencing pre-jump height. Second, experimental tests were carried out on sixteen juvenile trampoline gymnasts to collect data on these indicators. Third, factor analysis was applied to refine the initial indicator system and develop a formal evaluation framework. Finally, gray relational analysis was used to quantify the relationships between each indicator and pre-jump height. Results: The final indicator system encompassed five dimensions and sixteen representative variables. Gray relational analysis revealed that ten indicatorsstanding long jump, height, leg length, shoulder width, arm hang angle, ratio of counter jump height to pre-jump height, 30-second hanging leg raise, BMI, hip joint angle at landing, and state anxiety level -showed strong correlations (gray relational coefficient > 0.9) with pre-jump height. Three additional indicatorstrampoline-induced acrophobia, daily acrophobia, and ankle joint cushioningdemonstrated moderate correlations (coefficient 0.8-0.9). In contrast, time perception (10 seconds), supine leg raise (45°), and self-rotation perception showed weaker correlations (coefficient < 0.8).This study has established the indicator system consisting of 16 items of pre-jump height influencing factors and has identified the importance ranking of each indicator through gray relational analysis for juvenile trampoline gymnasts. These findings may serve as a scientific basis for developing targeted training programs and objective talent selection criteria, while also advancing gymnastics research by highlighting the interaction of physical, technical, and psychological factors in specialized jumping performance.