Allometric Scaling of Left Heart Structure and Function in Elite Cyclists: Development of Sport-Specific Prediction Equations

Herrera-Leaño, N, Malhotra, A, Cooper, R ORCID: 0000-0001-7482-828X, Robinson, S ORCID: 0000-0001-9461-9389, Ramcharan, T, Maxwell, J, Place, F, George, K ORCID: 0000-0002-5119-6651, Jones, N, Khoury, P, Ashley, EA, Haddad, F and Oxborough, D ORCID: 0000-0002-1334-3286 (2026) Allometric Scaling of Left Heart Structure and Function in Elite Cyclists: Development of Sport-Specific Prediction Equations. Journal of the American Heart Association, 15 (20). ISSN 2047-9980

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Abstract

BACKGROUND: Elite athletes frequently exceed conventional left ventricular (LV) and left atrial thresholds when guideline-recommended linear scaling for body size is applied, prompting unnecessary investigation. Few athlete-specific allometric equations yield percentage predicted values or Z scores. We aimed to develop allometric equations for LV and left atrial structure and function in elite cyclists, accounting for body size, sex, discipline, and heart rate, and to compare these with body surface area (BSA) indexing. METHODS: We evaluated 181 elite cyclists (105 male, 76 female; age 22.7±5.5 years; 128 endurance, 53 sprint) with normal preparticipation cardiac screening. Weighted least squares allometric regression determined optimal scaling exponents for height, weight, and BSA, with models advancing in complexity only when prediction accuracy significantly improved. Equations were externally validated in 62 independent elite male endurance cyclists. RESULTS: Men had larger BSA-scaled LV and left atrial size than women (both P<0.001). Many cyclists exceeded conventional thresholds (American Society of Echocardiography 2015: LV end-diastolic volume indexed to BSA 69.6%, LV end-systolic volume indexed to BSA 62.9%; British Society of Echocardiography 2020: LV end-diastolic volume indexed to BSA 50.8%, left atrial volume indexed to BSA 28.7%). Height provided superior allometric fit versus weight or BSA. Height, sex, discipline, and RR interval were key determinants. On external validation, only 6.5% exceeded the Z score threshold for LV end-diastolic volume indexed to BSA, compared with 90.3% classified abnormal by ASE guidelines. CONCLUSIONS: Height-based allometric scaling outperformed weight or BSA for cardiac dimensions and function in elite cyclists. These sport-specific equations, validated in an independent cohort, provide clinically usable percentage predicted values and Z scores that permit quantitative assessment rather than binary thresholds and may reduce misclassification of physiological adaptation as disease in preparticipation cardiac screening programs.

Item Type:	Article
Uncontrolled Keywords:	allometric scaling; athlete's heart; echocardiography; preparticipation cardiac screening; Z score; Z score; allometric scaling; athlete's heart; echocardiography; preparticipation cardiac screening; Humans; Male; Female; Bicycling; Young Adult; Athletes; Body Surface Area; Adult; Ventricular Function, Left; Heart Atria; Heart Ventricles; Atrial Function, Left; Predictive Value of Tests; Heart Rate; Reproducibility of Results; Prediction Methods, Machine; 32 Biomedical and Clinical Sciences; 3202 Clinical Sciences; Cardiovascular; Women's Health; Heart Disease; 4.2 Evaluation of markers and technologies; Cardiovascular; Humans; Male; Female; Bicycling; Young Adult; Athletes; Body Surface Area; Adult; Ventricular Function, Left; Heart Atria; Heart Ventricles; Atrial Function, Left; Predictive Value of Tests; Heart Rate; Reproducibility of Results; Prediction Methods, Machine; 1102 Cardiorespiratory Medicine and Haematology; 3201 Cardiovascular medicine and haematology
Subjects:	R Medicine > RC Internal medicine R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport and Exercise Sciences
Publisher:	Wiley
Date of acceptance:	11 September 2026
Date of first compliant Open Access:	4 November 2026
Date Deposited:	04 Nov 2026 13:25
Last Modified:	04 Nov 2026 13:25
DOI or ID number:	10.1161/JAHA.126.050142
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29815

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