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, though persistent disparities by sex, grade level, race/ethnicity, and socioeconomic status remain.
Key Findings
Results
Aerobic capacity in the healthy fitness zone increased substantially over the study period.
In 2006/07, 24.7% of students were in the HFZ for aerobic capacity.
By 2018/19, 35.6% of students were in the HFZ for aerobic capacity.
This represents a relative increase of 44.1% from baseline (p < 0.001).
Aerobic capacity showed the largest gains of the three fitness measures assessed.
Results
Push-up performance in the healthy fitness zone showed a small but statistically significant increase over the study period.
In 2006/07, 55.3% of students were in the HFZ for push-ups.
By 2018/19, 56.1% (SD = 0.56) of students were in the HFZ for push-ups.
This represents a relative increase of 1.4% from baseline (p < 0.001).
Push-ups showed the smallest relative improvement of the three fitness measures.
Results
Curl-up performance in the healthy fitness zone increased moderately over the study period.
In 2006/07, 65.0% of students were in the HFZ for curl-ups.
By 2018/19, 70.5% (SD = 0.54) of students were in the HFZ for curl-ups.
This represents a relative increase of 8.5% from baseline (p < 0.001).
Methods
The study utilized a large, longitudinal, population-level dataset spanning 13 years from New York City public schools.
The dataset included 2,272,575 unique students and 8,523,877 student-year observations.
Data were drawn from 1,721 public schools across grades 4 through 12.
The study period covered school years 2006/07 through 2018/19, described as the longest period for which US-based data are available.
Adjusted generalized estimating equations were used to determine the prevalence of being in the HFZ.
Performance was assessed using healthy fitness zones (HFZ), described as 'validated performance standards indicating whether individual fitness was sufficient for good overall health.'
Results
Persistent disparities in fitness were observed by sex, grade level, race/ethnicity, and home neighborhood socioeconomic status throughout the study period.
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 students compared to non-Hispanic Black and Hispanic students grew slightly over the study period.
Disparities persisted across all three fitness measures: aerobic capacity, push-ups, and curl-ups.
Day S, Nguyen C, Argenio K, Konty K, Dougan S, D'Agostino E, et al.. (2026). Trends in 4th-12th grade students' aerobic capacity and muscular strength and endurance: New York City public school students, 2006-2019.. Frontiers in public health. https://doi.org/10.3389/fpubh.2026.1682913