# Effects of a Daily Mile Program During Recess on Physical Fitness in Adolescents: A Comparative Pilot Study of Weekly Frequency and Gender Differences Among Students in a Region of Spain

## TL;DR

This study found that running a mile daily during recess can improve physical fitness in adolescents, with varying effects based on gender and how often the program is done.

## Contribution

The study provides new insights into how daily mile running during recess affects physical fitness in adolescents, considering gender and frequency differences.

## Key findings

- Daily mile running improved endurance and speed in adolescents, especially at higher frequencies.
- Gender differences in physical fitness were observed, with boys and girls showing distinct improvements.
- Lower limb strength and flexibility showed mixed or no significant changes after the program.

## Abstract

Background: Recess provides a valuable opportunity for physical activity for students at school. However, there is no clear evidence regarding the effects of running a mile daily on schoolchildren’s physical fitness. The objective of this study was to identify and evaluate the effects of running a mile daily during recess in a school setting over a 12-week period. Methods: The study included 68 students (39 boys and 29 girls) aged 13 to 16 years (14.45 ± 1.08) from secondary education (Spain). Participants were randomly assigned to one of three groups. Intervention Group 1 (IG1): one-mile run once per week (22 students). Intervention Group 2 (IG2): one-mile runs three times per week (21 students). Intervention Group 3 (IG3): one-mile runs five times per week (25 students). Physical fitness was assessed using the following tests: Broad jump (lower limb strength); Sit and Reach (lower limb flexibility); 4 × 10 m shuttle runs (speed, agility, and coordination); 10 × 5 m shuttle runs (displacement speed); 20 m shuttle run (Course Navette) (cardiorespiratory endurance). Results: Broad jump: No overall post-intervention differences were observed (p > 0.05), but there were pre-existing gender differences [boys outperform girls in IG2 and IG3 (p < 0.05)] that widened after the program, even appearing in IG1 (p = 0.031). Sit and Reach: No overall changes occurred (p > 0.05), but gender differences emerged in IG3 after the intervention [girls outperformed boys (p < 0.050)], and IG3 boys showed a decrease in flexibility after the program (p = 0.041). The 4 × 10 m shuttle runs: Initial differences between IG1 vs. IG3 disappeared after the intervention, with an overall increase in test time (p > 0.005). Pre-existing gender differences decreased, except in IG2 (boys remained faster; p < 0.001). The 10 × 5 m shuttle runs: Significant improvements were observed in all post-intervention groups (p = 0.003), with the greatest gains in IG3 boys (p < 0.001) and IG1 girls (p = 0.003). The 20 m shuttle run: Significant improvements occurred in IG1 and IG3 (p < 0.005), particularly in IG3 boys (p = 0.002) and IG1 girls (p = 0.019). Conclusions: Although effects varied by fitness component, intervention frequency, and gender, daily mile running was shown to be a viable strategy for improving aspects of fitness in adolescents, particularly endurance and speed, even at lower frequencies.