# Temporal Trends of Linear Speed and Change of Direction Performance in Italian Children

## TL;DR

The study found that Italian children's ability to change direction declined over 25 years, while their linear speed stayed the same.

## Contribution

This is the first long-term analysis of linear speed and change of direction trends in Italian children, adjusted for BMI.

## Key findings

- Change of direction performance declined over 25 years in Italian children.
- Linear speed performance remained stable despite changes in body mass index.
- The decline in change of direction was consistent across genders and ages.

## Abstract

Children tend to enjoy high-intensity activities that involve both linear speed (LS) and change of direction (COD), essential for sports performance. However, the results of trends in LS and COD have not been consistent over time. Therefore, our study aimed to investigate the temporal trends in LS and COD performance among 11–13 year old Italian children/preadolescents over 25 years, while minimizing the effect of anthropometric characteristics. A total of 3884 students were recruited between 1990 and 2010 and performed 4 x 5-m shuttle run, 30-m sprint, and 60-m speed tests. A weighted linear regression was performed to analyze the overall temporal trends in BMI-adjusted speed tests. The results showed an increase in mean 4 x 5-m shuttle run time, indicating a decrease in COD ability, while LS performance remained relatively stable over time. These trends were consistent across genders and ages. Our study concludes that LS test performance remained steady over decades, while COD ability declined with sex-based variations despite participants' early age. Our results offer crucial data for interventions to improve children's physical fitness: in particular for COD performance. PE teachers and coaches should prioritize improving COD over LS to improve these abilities and prevent physical fitness decline.