# Seasonal Comparison of Pre-Adolescent Soccer Players’ Physical Performance Using an Objective Physical Test Battery

## TL;DR

This study tracks physical improvements in young male soccer players over a season using objective tests and wearable sensors.

## Contribution

The study introduces an objective test battery and sensor-based metrics to evaluate seasonal physical performance changes in pre-adolescent soccer players.

## Key findings

- Significant improvements were observed in quick feet (19.7%), stability (10.9%), and countermovement jumps (9.6%).
- Four principal components—strength-power, balance, speed-agility, and stiffness—explained over 80% of the variance in performance data.

## Abstract

Background/Objective: Soccer is a multifactorial sport, requiring physical, psychological, technical, and tactical skills to succeed. Monitoring and comparing physical characteristics over time is essential to assess players’ development, customize training, and prevent injury. The use of wearable sensors is essential to provide accurate and objective physical data. Methods: In this longitudinal study, 128 male adolescent soccer players (from Under 12 to Under 19) were evaluated at two time points (pre- and post-season). Participants completed the Euleria Lab test battery, including stability, countermovement and consecutive jumps, agility, and quick feet tests. A single Inertial Measurement Unit sensor provided quantitative data on fifteen performance metrics. Percentage changes were compared to the Smallest Worthwhile Changes to assess significant changes over time. Results: The results showed significant improvements in most variables, including a 19.7% increase in quick feet, 10.9% in stability, and 9.6% in countermovement jumps. In principal component analysis, we identified four principal components—strength-power, balance, speed-agility, and stiffness—that explained over 80% of the variance. Conclusions: These findings align with previous studies assessing seasonal changes in adolescent soccer players, showing that the proposed test battery seems to be adequate to highlight physical performance changes and provide coaches with meaningful data to customize training and reduce injury rates.