Abstract
Background—exercise-induced muscle damage (EIMD) and internal exercise load are increased after competing in ultraendurance events such as mountain marathons. Adequate carbohydrate (CHO) intake during exercise optimizes athletic performance and could limit EIMD, reduce internal exercise load and, thus, improve recovery. Therefore, the aim of this study was to research into and compare the effects of high CHO intake (120 g/h) in terms of CHO intake recommendation (90 g/h) and regular CHO intake performed by ultraendurance athletes (60 g/h) during a mountain marathon, on exercise load and EIMD markers (creatine kinase (CK), lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), urea and creatinine). Materials and Methods—a randomized trial was carried out on 20 male elite runners who had previously undertaken nutritional and gut training, and who consumed different CHO dosages according to experimental (EXP—120 g/h), control (CON—90 g/h) and low CHO intake (LOW—60 g/h) groups during a ~4000 m cumulative slope mountain marathon. EIMD markers were analyzed before the race and 24 h afterwards. Internal exercise load was calculated based on rate of perceived exertion (RPE) during and after the marathon event. Results—internal exercise load during the mountain marathon was significantly lower (p = 0.019; η2p = 0.471) in EXP (3805 ± 281 AU) compared to LOW (4688 ± 705 AU) and CON (4692 ± 716 AU). Moreover, results revealed that the EXP group evidenced significantly lower CK (p = 0.019; η2p = 0.373), LDH (p < 0.001; η2p = 0.615) and GOT (p = 0.003; η2p = 0.500) values 24 h after the mountain marathon race compared to LOW and CON. Along these lines, EIMD and exercise load evidenced a close correlation (R = 0.742; p < 0.001). Conclusion: High CHO intake (120 g/h) during a mountain marathon could limit the EIMD observed by CK, LDH and GOT and internal exercise load compared to CHO ingestion of 60 and 90 g/h.
Highlights
Ultraendurance events such as mountain marathons (42,195 km) represent one of the major physical challenges for athletes, as they potentially involve various physiological and pathophysiologicalNutrients 2020, 12, 1367; doi:10.3390/nu12051367 www.mdpi.com/journal/nutrientsNutrients 2020, 12, 1367 responses which increase internal exercise load and fatigue [1,2,3]
Results revealed that the experimental group (EXP) group evidenced significantly lower creatine kinase (CK) (p = 0.019; η2 p = 0.373), lactate dehydrogenase (LDH) (p < 0.001; η2 p = 0.615) and glutamic oxaloacetic transaminase (GOT) (p = 0.003; η2 p = 0.500) values 24 h after the mountain marathon race compared to low carbohydrate group (LOW) and control group (CON)
Observed by CK, LDH and GOT and internal exercise load compared to CHO ingestion of 60 and 90 g/h
Summary
Ultraendurance events such as mountain marathons (42,195 km) represent one of the major physical challenges for athletes, as they potentially involve various physiological and pathophysiologicalNutrients 2020, 12, 1367; doi:10.3390/nu12051367 www.mdpi.com/journal/nutrientsNutrients 2020, 12, 1367 responses which increase internal exercise load and fatigue [1,2,3]. Considering the variability of the terrain, characteristics and lack of similarity in terms of physical demands when referring to different mountain events, distance by itself does not seem to be a reliable parameter for quantifying physiological and metabolic demands. Other parameters such as physiological intensity, internal exercise load and biochemical changes might represent a better understanding of these event requirements [4,5]. This phenomenon could be affected by several psychophysiological and metabolic factors such as rate of perceived exertion (RPE), glycogen depletion, heart rate, dehydration, and exercise-induced muscle damage (EIMD) [3,5,7,8,9,10].
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