Stature is the key: A systematic review and meta-analysis on the role of stature and body mass in physical fitness through allometric modeling.

OBJECTIVES

To evaluate how stature and body mass influence youth physical fitness performance across different test modalities using allometric modeling, and to quantify domain-specific allometric exponents for stature and body mass.

DESIGN

Systematic review and meta-analysis.

METHODS

A comprehensive literature search was conducted in PubMed and Web of Science (July 2024;CRD420251030848). Sixteen cross-sectional studies involving youth populations (aged 7-19 years) met inclusion criteria. Extracted allometric exponents for stature and body mass were synthesized across four fitness domains: cardiorespiratory fitness, upper-limb strength, lower-limb explosive strength, and speed-agility. Random-effects meta-analyses were performed using Restricted Maximum Likelihood estimation. Heterogeneity was assessed via I2 and Cochran's Q.

RESULTS

Stature showed a consistently positive association with performance across all domains, with allometric exponents ranging from 0.40 to 1.39 (p < 0.001). Body mass demonstrated divergent patterns: negative exponents for cardiorespiratory fitness (boys: -0.24; girls: -0.22), explosive strength, and speed-agility; but positive associations for upper limb strength (boys: 0.31; girls: 0.30). All models showed high heterogeneity; moderation and sensitivity analyses confirmed test-type-independent results.

CONCLUSIONS

Stature shows a consistent positive association with physical fitness independently of test modalities, whereas body mass exponents are domain-specific, negative in weight-bearing tasks and positive in upper-limb strength. These pooled estimates suggest clear trends in size-performance scaling, though substantial heterogeneity and the absence of independent model validation limit their generalizability. Allometric modeling remains a useful approach to reduce size-related bias when applied alongside sport-specific and developmental considerations.