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article 2025 9 pages

Technical classification of professional cycling stages using unsupervised learning: implications for performance variability

Igor Garcia-Atutxa, Ekaitz Dudagoitia Barrio, Francisca Villanueva-Flores

Journal
Frontiers in Sports and Active Living
DOI
10.3389/fspor.2025.1661456
Publication type
Original Research
Population
professional cycling
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Abstract

Introduction:

In professional cycling, the technical characteristics of race stages significantly influence group dynamics and performance variability among competitors. However, stage classifications have traditionally been subjective, lacking a robust empirical foundation. This study aimed to develop an objective, technical classification of professional cycling stages using unsupervised learning (KMeans) and analyze how these categories relate to collective performance variability, measured by the coefficient of variation (CV) of finish times.

Methods:

Technical data and official results from 439 international race stages conducted between 2017 and 2023 were analyzed. The technical variables included distance, total vertical gain, average relative elevation, and percentages of paved and unpaved surfaces.

Results:

Cluster validation via Bootstrap analysis demonstrated high stability (mean silhouette index = 0.62 ± 0.03), confirming six clearly distinct technical stage groups. Results indicated that stages characterized by higher relative elevation and greater proportions of unpaved surfaces exhibited higher performance variability (higher CV),whereas less technically demanding stages showed lower variability; relative elevation emerged as the strongest predictor of CV (β = 0.42, p  = 0.23,   = 0.18,   = 0.11,   = 0.315).

Description

The study develops a technical classification of cycling stages and analyzes its impact on performance variability.