# Trends in 4th−12th grade students' aerobic capacity and muscular strength and endurance: New York City public school students, 2006–2019

## TL;DR

This study tracks changes in aerobic capacity and muscular strength among NYC public school students from 2006 to 2019, showing overall improvements but persistent disparities.

## Contribution

The study provides the longest US-based longitudinal analysis of youth fitness trends using NYC FITNESSGRAM data.

## Key findings

- Aerobic capacity in healthy fitness zones increased by 44.1% from 2006/07 to 2018/19.
- Muscular endurance for push-ups and curl-ups also improved, but disparities persisted by sex, race, and socioeconomic status.
- Non-Hispanic White students outperformed non-Hispanic Black and Hispanic students over time.

## Abstract

Systematically monitoring youth fitness over time is critical for designing and implementing policies and interventions to maintain/increase youth fitness and reduce the burden of non-communicable disease. This study describes trends in student fitness over school years 2006/07–2018/19, the longest period for which US-based data are available.

This observational, longitudinal study uses 13 years of population-weighted data from the New York City (NYC) FITNESSGRAM from 2,272,575 unique students (8,523,877 student-year observations) in 4th−12th grades from 1,721 public schools. Sex-and age-specific performance was assessed using healthy fitness zones (HFZ), validated performance standards indicating whether individual fitness was sufficient for good overall health. Adjusted generalized estimating equations determined the prevalence of being in the HFZ for aerobic capacity, push-ups, and curl-ups for all students, and by student sex, grade level, race/ethnicity, and home neighborhood socioeconomic status (SES).

In 2006/07, 24.7% of students were in the HFZ for aerobic capacity, 55.3% for push-ups, and 65.0% for curl-ups. By 2018–19, 35.6% were in the HFZ for aerobic capacity (a relative increase of 44.1% from baseline; p < 0.001); 56.1% (SD = 0.56) for push-ups (1.4% relative increase; p < 0.001); and 70.5% (SD = 0.54) for curl-ups (8.5% relative increase; p < 0.001). Stratified models demonstrated persistent differences in the proportion of students in the HFZ by sex, school level, and home neighborhood SES. Gaps between non-Hispanic White compared to non-Hispanic Black and Hispanic students grew slightly.

Thirteen years of data from the largest school district in the nation demonstrate overall improvements in student fitness performance on all three tests, with the largest gains seen for aerobic capacity. However, continued work is necessary to address persistent disparities in NYC youth aerobic capacity and muscular strength and endurance by sex, grade level, race/ethnicity, and socioeconomic status.