Mapping five decades of high-intensity interval training research (1977-2026): database sensitivity, intellectual structure, and thematic development

To characterize HIIT research while testing how database membership, document eligibility, and keyword metadata affect bibliometric representations of the field.

Archived Web of Science (WoS), Scopus, and PubMed exports were reconstructed through documented deduplication and retrospective computational metadata screening. The primary corpus comprised 7,141 research articles published from 1977 to the March 2026 snapshot. Analyses included database sensitivity, Bradford zones and cumulative-model fit, identifier-based Lotka estimation, source-specific citations, WoS reference co-citation, author-keyword mapping, volume-balanced thematic periods, and Scopus affiliation-country collaboration.

Of 18,578 record instances, 8,365 unique records remained after deduplication; 1,224 were excluded under the documented rules. Annual output increased from 80 articles in 2013 to 898 in 2025. Scopus membership covered 94.17% of the primary union, compared with 71.63% for WoS and 71.92% for PubMed. Top-20 keyword sets were similar across single-source subsets (Jaccard = 0.905-1.000), whereas keyword-field and network-size choices produced 3-8 themes. The 19 core journal identities contributed 33.61% of articles. Among 24,074 Scopus author identifiers, the estimated Lotka exponent was β = 2.447; both the fitted and classical full-range models failed bootstrap goodness-of-fit tests (p = 0.001). WoS co-citation identified four strongly interconnected reference communities, and the primary author-keyword map contained seven themes. Including reviews increased the corpus to 8,074 and the PubMed-only contribution from 166 to 876 records.

Broad topic visibility was comparatively stable, but database-specific contributions and thematic granularity depended on eligibility and metadata decisions. Source-resolved indicators and explicit sensitivity analyses provide a more defensible representation than an unqualified merged-data map. Findings describe bibliographic structure, not intervention effectiveness; historical search-date precision and independent screening agreement remain limitations.