Purpose: To evaluate the effects of a trail-running race on muscle oxidative function by measuring pulmonary gas exchange variables and muscle fractional O2 extraction. Methods: Eighteen athletes were evaluated before (PRE) and after (POST) a trail-running competition of 32 or 50 km with 2000 or 3500 m of elevation gain, respectively. During the week before the race, runners performed an incremental uphill running test and an incremental exercise by utilizing a 1-leg knee extension ergometer. The knee extension exercise was repeated after the end of the race. During the knee extension test, the authors measured oxygen uptake () and micromolar changes in deoxygenated hemoglobin (Hb)+myoglobin (Mb) concentrations (Δ[deoxy(Hb+Mb)]) on vastus lateralis with a portable near-infrared spectroscopy. Results: was lower at POST versus PRE (−23.9% [9.0%]; P < .001). at POST was lower than at the same workload at PRE (−8.4% [15.6%]; P < .050). Peak power output and time to exhaustion decreased at POST by −23.7% (14.3%) and −18.3% (11.3%), respectively (P < .005). At POST, the increase of Δ[deoxy(Hb+Mb)] as a function of work rate, from unloaded to peak, was less pronounced (from 20.2% [10.1%] to 64.5% [21.1%] of limb ischemia at PRE to 16.9% [12.7%] to 44.0% [18.9%] at POST). Peak Δ[deoxy(Hb+Mb)] values were lower at POST (by −31.2% [20.5%]; P < .001). Conclusions: Trail running leads to impairment in skeletal muscle oxidative metabolism, possibly related to muscle damage from repeated eccentric contractions. In association with other mechanisms, the impairment of skeletal muscle oxidative metabolism is likely responsible for the reduced exercise capacity and tolerance during and following these races.
Nicola Giovanelli, Lea Biasutti, Desy Salvadego, Hailu K. Alemayehu, Bruno Grassi and Stefano Lazzer
Gerard Carmona, Emma Roca, Mario Guerrero, Roser Cussó, Alfredo Irurtia, Lexa Nescolarde, Daniel Brotons, Josep L. Bedini and Joan A. Cadefau
To investigate changes after a mountain ultramarathon (MUM) in the serum concentration of fast (FM) and slow (SM) myosin isoforms, which are fiber-type-specific sarcomere proteins. The changes were compared against creatine kinase (CK), a widely used fiber-sarcolemma-damage biomarker, and cardiac troponin I (cTnI), a widely used cardiac biomarker.
Observational comparison of response in a single group of 8 endurance-trained amateur athletes. Time-related changes in serum levels of CK, cTnI, SM, and FM from competitors were analyzed before, 1 h after the MUM, and 24 and 48 h after the start of the MUM by 1-way ANOVA for repeated measures or Friedman and Wilcoxon tests. Pearson correlation coefficient was employed to examine associations between variables.
While SM was significantly (P = .009) increased in serum 24 h after the beginning of the MUM, FM and cTnI did not change significantly. Serum CK activity peak was observed 1 h after the MUM (P = .002). Moreover, serum peaks of CK and SM were highly correlated (r = .884, P = .004).
Since there is evidence of muscle damage after prolonged mountain running, the increase in SM serum concentration after a MUM could be indirect evidence of slow- (type I) fiber-specific sarcomere disruptions.
Martin D. Hoffman
with ultramarathon running, mountain running is included in the figure to be thorough. Off-road running that is not specified in the figure also includes cross-country running and various types of orienteering, adventure, and obstacle foot races. Off-road running also includes races on indoor or
Louise M. Burke, Linda M. Castell, Douglas J. Casa, Graeme L. Close, Ricardo J. S. Costa, Ben Desbrow, Shona L. Halson, Dana M. Lis, Anna K. Melin, Peter Peeling, Philo U. Saunders, Gary J. Slater, Jennifer Sygo, Oliver C. Witard, Stéphane Bermon and Trent Stellingwerff
Federations (IAAF), recognizes a number of distinct disciplines: sprints, middle/long distance, hurdles, and relays on the track; throws and jumps on the field; the combined events of heptathlon and decathlon; road running; race walks; cross-country; and mountain running and ultrarunning ( www.iaaf.org ). The
Nicola Giovanelli, Filippo Vaccari, Mirco Floreani, Enrico Rejc, Jasmine Copetti, Marco Garra, Lea Biasutti and Stefano Lazzer
, mountain running, parkour) for 9.9 (3.5) hours per week on average. They were informed about the study protocol and read and signed an informed consent before starting the measurements. The study was approved by the local institutional review board. Table 1 Physiological Characteristics and Training Status
Peter Peeling, Linda M. Castell, Wim Derave, Olivier de Hon and Louise M. Burke
immunity in endurance athletes . British Journal of Sports Medicine, 44 ( 4 ), 222 – 226 . doi:10.1136/bjsm.2007.044628 10.1136/bjsm.2007.044628 da Costa , R. , Knechtle , B. , Tarnopolsky , M. , & Hoffman , M. ( 2019 ). Nutrition for ultra-marathons and mountain running . International