{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:37:29Z","timestamp":1785418649048,"version":"3.56.0"},"reference-count":31,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T00:00:00Z","timestamp":1783296000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["2025M783217"],"award-info":[{"award-number":["2025M783217"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"award":["2025M783217"],"award-info":[{"award-number":["2025M783217"]}],"id":[{"id":"https:\/\/ror.org\/0426zh255","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Life"],"abstract":"<jats:p>Firefighters routinely perform short-distance sprints while wearing or carrying occupational gear. Nevertheless, how fatigue interacts with task-specific loading to shape the distribution of mechanical work across lower-limb joints remains poorly understood. This study aimed to determine how fatigue state and task-specific rescue loading affect sprint performance, impact loading, lower-limb joint mechanics, joint work contribution, and muscle activation in male firefighters. Fifty-three male firefighters completed four simulated rescue sprinting tasks under five fatigue conditions: non-fatigue, whole-body fatigue, and mild, moderate, and severe local knee extensor fatigue. Tasks included unloaded sprinting and 7, 20, and 30 kg task-specific rescue-load conditions. Kinematic, kinetic, and electromyographic data were collected during the stance phase of the dominant limb. Mild local fatigue was associated with a sprinting speed comparable to the non-fatigue condition and higher than that under whole-body or moderate-to-severe local fatigue. Progressively heavier task-specific rescue loads decreased sprinting speed, prolonged stance time, increased knee work contribution, and decreased ankle work contribution, indicating a redistribution of stance-phase mechanical work from the ankle toward the knee. This compensatory pattern was further modulated by treadmill-induced global locomotor fatigue. In conclusion, this ankle-to-knee redistribution may help firefighters complete high-load rescue sprinting, but it may also increase knee mechanical demand, particularly under global locomotor fatigue.<\/jats:p>","DOI":"10.3390\/life16071123","type":"journal-article","created":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T08:05:38Z","timestamp":1783325138000},"page":"1123","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Task-Specific Rescue Loading Redistributes Lower Limb Joint Work During Simulated Sprinting Across Fatigue States in Firefighters"],"prefix":"10.3390","volume":"16","author":[{"given":"Junqiang","family":"Zhang","sequence":"first","affiliation":[{"name":"School of Physical Education, Shaanxi Normal University, Xi\u2019an 710119, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xueyi","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Physical Education, Shaanxi Normal University, Xi\u2019an 710119, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Min","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Physical Education and Art, East China University of Technology, Nanchang 330013, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1730-8573","authenticated-orcid":false,"given":"Xinxin","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Physical Education, Shaanxi Normal University, Xi\u2019an 710119, China"},{"name":"College of Physical Education and Health, Guangxi Normal University, Guilin 541006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1080\/10803548.2023.2294627","article-title":"The global prevalence of musculoskeletal disorders among firefighters: A systematic review and meta-analysis","volume":"30","author":"Khoshakhlagh","year":"2024","journal-title":"Int. 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