García-Valiente et al. 2026, Muscle, neuromuscular and cardiac damage in trail running

Narrative systematic review (PRISMA 2020, PROSPERO-registered; Muscles 5(1):9) of 15 observational studies and 247 trail runners (under 10% women). Trail running, especially events with long downhill, eccentric-loaded sections, produces marked but transient post-race rises in muscle-damage biomarkers (creatine kinase, often above 3000 U/L; ALT), significant short-term reductions in neuromuscular force (squat jump, maximal voluntary contraction) lasting several days, and reversible elevations in cardiac biomarkers (CK-MB, troponins, NT-proBNP) that reflect acute cardiac stress rather than permanent myocardial injury. No meta-analysis or GRADE was performed and the included studies were small and heterogeneous. Limited.