{ "abstract": "Background\n\nInspiratory muscle training (IMT) and plyometric exercise are established conditioning modalities that elicit distinct physiological adaptations, yet their comparative effects on respiratory function and autonomic regulation in youth athletes remain unclear. The pupillary light reflex (PLR) provides a non-invasive index of autonomic activity and may offer new insight into training-induced adaptations. This study examined the effects of a 12-week IMT versus plyometric training program on pulmonary function and PLR dynamics in youth middle-distance runners.Methods\n\nNinety youth middle-distance runners (aged 14-18 years) were randomly assigned to an IMT group (n = 30), a plyometric training group (n = 30), or a control group (n = 30). The prespecified primary outcome was forced expiratory volume in 1 second (FEV₁); secondary outcomes included other spirometry parameters (forced expiratory volume [FEV₁], forced vital capacity [FVC], forced expiratory volume/forced vital capacity [FEV₁/FVC] ratio, peak expiratory flow [PEF], and maximal inspiratory pressure [MIP]) and PLR metrics (initial diameter, constriction velocity, maximum constriction, re-dilation velocity) served as secondary/exploratory outcomes. Assessments were conducted at baseline and 12 weeks (no interim timepoint was assessed). Of 90 randomized participants, 86 (95.6%) completed the study and were included in the complete-case primary analysis.Results\n\nIMT led to marked gains in FEV₁ (4.12 ± 0.23 to 4.45 ± 0.25 L, p < 0.001), FVC (4.89 ± 0.31 to 5.28 ± 0.33 L, p < 0.001), and PEF (628 ± 45 to 672 ± 48 L/min, p < 0.001). PLR constriction velocity also improved significantly (5.2 ± 0.8 to 6.1 ± 0.9 mm/s, p < 0.01). In comparison, plyometric training yielded modest but significant improvements in FEV₁ (4.08 ± 0.26 to 4.25 ± 0.28 L, p < 0.05) and increased PLR re-dilation velocity (3.1 ± 0.6 to 3.8 ± 0.7 mm/s, p < 0.05). No significant changes were observed in the control group.Conclusion\n\nIn this complete-case analysis, IMT produced greater adjusted improvements in pulmonary function than plyometric training in youth middle-distance runners, while both modalities were associated with distinct changes in pupillary light reflex indices (constriction velocity with IMT; re-dilation velocity with plyometric training) that may reflect differential autonomic adaptation. As running performance was not assessed, these findings should be interpreted as physiological rather than performance evidence, and the potential value of combining both modalities warrants prospective testing.", "abstract_shown": true, "affiliations": [ "Department of Physical Education & Sports, Pondicherry University, Puducherry, India.", "Symbiosis School of Sports Sciences, Symbiosis International (Deemed University), Pune, Maharashtra, India.", "Department of Physical Education Pedagogy, Lakshmibai National Institute of Physical Education, Gwalior, India.", "Faculty of Sport and Exercise Science, UCLan University of Cyprus, Pyla, Cyprus.", "Montenergin Sports Academy, Podgorica, Montenegro.", "Department of Physical Education and Sport, Faculty of Physical Education and Sport, Aurel Vlaicu University of Arad, Arad, Romania.", "Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.", "Department of Sports, Recreation and Wellness, Symbiosis International (Deemed University), Hyderabad Campus, Modallaguda (V), Nandigama (M), Rangareddy, Telangana, India." ], "article_type": "research article", "arxiv": null, "author_total": 10, "authors": [ { "affs": [ 0 ], "name": "Vinu W" }, { "affs": [ 1 ], "name": "Josyula Tejaswi" }, { "affs": [ 0 ], "name": "Dilshith Azeezul Kabeer" }, { "affs": [ 2 ], "name": "Debajit Karmakar" }, { "affs": [ 0 ], "name": "Ibnu Noufal Kambitta Valappil" }, { "affs": [ 3 ], "name": "Koulla Parpa" }, { "affs": [ 4 ], "name": "Borko Katanic" }, { "affs": [ 5 ], "name": "Vlad Adrian Geantă" }, { "affs": [ 6 ], "name": "Jolita Vveinhardt" }, { "affs": [ 1, 7 ], "name": "Karuppasamy Govindasamy" } ], "bibtex": "https://research.draconitic.com/paper/4wfdj537k1tdq.bib", "cited_by": 0, "doi": "10.3389/fphys.2026.1781766", "fulltext_url": "https://europepmc.org/articles/PMC13713271", "id": "4wfdj537k1tdq", "issns": [ "1664-042X" ], "landing_url": "https://europepmc.org/article/MED/42952497", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "heading", "Original Research" ], [ "openalex", "2732|Sports Performance and Training" ] ], "openalex": "W7221817085", "pdf_url": "https://europepmc.org/articles/PMC13713271?pdf=render", "pmcid": "PMC13713271", "pmid": "42952497", "published": "2026-10-14", "publisher": "Frontiers Media SA", "ris": "https://research.draconitic.com/paper/4wfdj537k1tdq.ris", "sources": [ { "first_seen": "2026-10-31T00:20:34Z", "native_id": "MED:42952497", "source": "europepmc", "url": "https://europepmc.org/article/MED/42952497" }, { "first_seen": "2026-10-31T12:23:51Z", "native_id": "PMC13713271", "source": "pmc", "url": "https://doi.org/10.3389/fphys.2026.1781766" } ], "subjects": [ { "field": "medicine", "origin": "openalex:2732|Sports Performance and Training", "subfield": "surgery" } ], "title": "Effects of twelve-week inspiratory muscle vs. plyometric training on pulmonary function and pupillary light reflex in youth middle-distance runners-a three-arm randomized controlled trial.", "title_text": "Effects of twelve-week inspiratory muscle vs. plyometric training on pulmonary function and pupillary light reflex in youth middle-distance runners-a three-arm randomized controlled trial.", "type": "peer-reviewed", "updated_at": "2026-11-01T12:20:58Z", "url": "https://research.draconitic.com/paper/4wfdj537k1tdq", "venue": "Frontiers in physiology", "versions": [] }