# Investigating the key influencing factors of pre-jump height in juvenile trampoline gymnasts using grey relational analysis

## TL;DR

This study identifies key factors affecting pre-jump height in young trampoline gymnasts to improve training and talent selection.

## Contribution

A novel indicator system and grey relational analysis to rank factors influencing pre-jump height in juvenile gymnasts.

## Key findings

- Ten indicators showed strong correlations with pre-jump height, including physical and psychological factors.
- Three indicators showed moderate correlations, while others had weak relationships.
- The findings provide a scientific basis for training and talent selection in trampoline gymnastics.

## Abstract

Achieving greater pre-jump elevation is essential for trampoline gymnasts to attain high-level competition performance. This study aimed to explore the key influencing factors of pre-jump height in juvenile trampoline gymnasts, thereby providing a rationale for training programs and talent selection criteria.

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 16 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, grey relational analysis was used to quantify the relationships between each indicator and pre-jump height.

The final indicator system encompassed 5 dimensions and 16 representative variables. The grey relational analysis revealed that 10 indicators—standing long jump, height, leg length, shoulder width, arm hang angle, ratio of counter-jump height to pre-jump height, 30-s hanging leg raise, BMI, hip joint angle at landing, and state anxiety level—showed strong correlations (grey relational coefficient > 0.9) with pre-jump height. Furthermore, three additional indicators—trampoline-induced acrophobia, daily acrophobia, and ankle joint cushioning—demonstrated moderate correlations (coefficient 0.8–0.9). In contrast, time perception (10 s), supine leg raise (45°), and self-rotation perception showed weaker correlations (coefficient < 0.8).

This study established an indicator system consisting of 16 items of pre-jump height influencing factors and identified the importance ranking of each indicator using grey relational analysis in juvenile trampoline gymnasts. These findings may serve as a scientific basis for developing targeted training programs and objective talent selection criteria while advancing gymnastics research by highlighting the interaction of physical, technical, and psychological factors in specialized jumping performance.