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Muscle and intestinal damage in triathletes.
Tota, Ł, Piotrowska, A, Pałka, T, Morawska, M, Mikuľáková, W, Mucha, D, Żmuda-Pałka, M, Pilch, W
PloS one. 2019;(1):e0210651
Abstract
The aim of the paper was to assess indicators of muscle and intestinal damage in triathletes. The study involved 15 triathletes whose objective for the season was to start in the XTERRA POLAND 2017 event (1,500-m swimming, 36-km cycling, and 10-km mountain running). Before the 14-week preparatory period, the competitors' body composition was measured, aerobic capacity was tested (graded treadmill test) and blood samples were collected to determine markers showing the level of muscle and intestinal damage. Subsequent tests for body composition were carried out before and after the competition. Blood samples for biochemical indicators were collected the day before the competition, after the completed race, and 24 and 48 hours later. A significant decrease in body mass was observed after completing the race (-3.1±1.5%). The mean maximal oxygen uptake level among the studied athletes equalled 4.9±0.4 L·min-1, 58.8±4.5 mL·kg-1·min-1. The significant increase in concentrations of cortisol, c-reactive protein and myoglobin after the competition, significantly correlated with the significant increase in zonulin concentration (post 1h: r = 0.88, p = 0.007, r = 0,79, p = 0.001, r = 0.78, p = 0.001, and post 12h: r = 0.75, p = 0.01, r = 0.71, p = 0.011, r = 0.83, p = 0.02). No significant changes in the concentration of tumour necrosis factor alpha among the examined competitors were noted at following stages of the study. The results of our research showed that in order to monitor overload in the training of triathletes, useful markers reflecting the degree of muscle and intestinal damage include cortisol, testosterone, testosterone to cortisol ratio, c-reactive protein, myoglobin and zonulin. Changes in muscle cell damage markers strongly correlated with changes in zonulin concentration at particular stages of the study. Thus, one can expect that the concentrations of markers depicting the level of muscle cell damage after an intense and long-lasting effort will significantly influence the level of the intestinal barrier.
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Health-Related Physical Fitness in Healthy Untrained Men: Effects on VO2max, Jump Performance and Flexibility of Soccer and Moderate-Intensity Continuous Running.
Milanović, Z, Pantelić, S, Sporiš, G, Mohr, M, Krustrup, P
PloS one. 2015;(8):e0135319
Abstract
The purpose of this study was to determine the effects of recreational soccer (SOC) compared to moderate-intensity continuous running (RUN) on all health-related physical fitness components in healthy untrained men. Sixty-nine participants were recruited and randomly assigned to one of three groups, of which sixty-four completed the study: a soccer training group (SOC; n = 20, 34±4 (means±SD) years, 78.1±8.3 kg, 179±4 cm); a running group (RUN; n = 21, 32±4 years, 78.0±5.5 kg, 179±7 cm); or a passive control group (CON; n = 23, 30±3 years, 76.6±12.0 kg, 178±8 cm). The training intervention lasted 12 weeks and consisted of three 60-min sessions per week. All participants were tested for each of the following physical fitness components: maximal aerobic power, minute ventilation, maximal heart rate, squat jump (SJ), countermovement jump with arm swing (CMJ), sit-and-reach flexibility, and body composition. Over the 12 weeks, VO2max relative to body weight increased more (p<0.05) in SOC (24.2%, ES = 1.20) and RUN (21.5%, ES = 1.17) than in CON (-5.0%, ES = -0.24), partly due to large changes in body mass (-5.9, -5.7 and +2.6 kg, p<0.05 for SOC, RUN and CON, respectively). Over the 12 weeks, SJ and CMJ performance increased more (p<0.05) in SOC (14.8 and 12.1%, ES = 1.08 and 0.81) than in RUN (3.3 and 3.0%, ES = 0.23 and 0.19) and CON (0.3 and 0.2%), while flexibility also increased more (p<0.05) in SOC (94%, ES = 0.97) than in RUN and CON (0-2%). In conclusion, untrained men displayed marked improvements in maximal aerobic power after 12 weeks of soccer training and moderate-intensity running, partly due to large decreases in body mass. Additionally soccer training induced pronounced positive effects on jump performance and flexibility, making soccer an effective broad-spectrum fitness training intervention.
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Ingesting a high-dose carbohydrate solution during the cycle section of a simulated Olympic-distance triathlon improves subsequent run performance.
McGawley, K, Shannon, O, Betts, J
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2012;(4):664-71
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Abstract
The well-established ergogenic benefit of ingesting carbohydrates during single-discipline endurance sports has only been tested once within an Olympic-distance (OD) triathlon. The aim of the present study was to compare the effect of ingesting a 2:1 maltodextrin/fructose solution with a placebo on simulated OD triathlon performance. Six male and 4 female amateur triathletes (age, 25 ± 7 years; body mass, 66.8 ± 9.2 kg; peak oxygen uptake, 4.2 ± 0.6 L·min(-1)) completed a 1500-m swim time-trial and an incremental cycle test to determine peak oxygen uptake before performing 2 simulated OD triathlons. The swim and cycle sections of the main trials were of fixed intensities, while the run section was completed as a time-trial. Two minutes prior to completing every quarter of the cycle participants consumed 202 ± 20 mL of either a solution containing 1.2 g·min(-1) of maltodextrin plus 0.6 g·min(-1) of fructose at 14.4% concentration (CHO) or a sugar-free, fruit-flavored drink (PLA). The time-trial was 4.0% ± 1.3% faster during the CHO versus PLA trial, with run times of 38:43 ± 1:10 min:s and 40:22 ± 1:18 min:s, respectively (p = 0.010). Blood glucose concentrations were higher in the CHO versus PLA trial (p < 0.001), while perceived stomach upset did not differ between trials (p = 0.555). The current findings show that a 2:1 maltodextrin/fructose solution (1.8 g·min(-1) at 14.4%) ingested throughout the cycle section of a simulated OD triathlon enhances subsequent 10-km run performance in triathletes.
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Neuromuscular consequences of an extreme mountain ultra-marathon.
Millet, GY, Tomazin, K, Verges, S, Vincent, C, Bonnefoy, R, Boisson, RC, Gergelé, L, Féasson, L, Martin, V
PloS one. 2011;(2):e17059
Abstract
We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM) with 9500 m of positive and negative elevation change. For this purpose, (i) the fatigue induced by the MUM and (ii) the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF) and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22), and 2, 5, 9 and 16 days after the MUM (n = 11) in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (-35% [95% CI: -28 to -42%] and -39% [95% CI: -32 to -46%] for KE and PF, respectively), with alteration of maximal voluntary activation, mainly for KE (-19% [95% CI: -7 to -32%]). Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144 ± 94 to 13,633 ± 12,626 UI L(-1)), myoglobin (from 32 ± 22 to 1,432 ± 1,209 µg L(-1)), and C-Reactive Protein (from <2.0 to 37.7 ± 26.5 mg L(-1)). Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration) were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline.
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The effect of the glycemic index of an evening meal on the metabolic responses to a standard high glycemic index breakfast and subsequent exercise in men.
Stevenson, E, Williams, C, Nute, M, Swaile, P, Tsui, M
International journal of sport nutrition and exercise metabolism. 2005;(3):308-22
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The present study investigated the effect of the glycemic index of an evening meal on responses to a standard high glycemic index (HGI) breakfast the following morning. The metabolic responses to exercise 3 h after breakfast were also investigated. Seven active males completed 2 trials. In each trial, participants were provided with an evening meal on day 1, which was composed of either HGI or LGI (high or low glycemic index) carbohydrates. On day 2, participants were provided with a standard HGI breakfast and then performed a 60 min run at 65% VO(2max) 3 h later. Plasma glucose and serum insulin concentrations following breakfast were higher in the HGI trial compared to the LGI trial (P < 0.05). During exercise, there were no differences in substrate utilization. The results suggest that consuming a single LGI evening meal can improve glucose tolerance at breakfast but the metabolic responses to subsequent exercise were not affected.
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Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners.
Schwellnus, MP, Nicol, J, Laubscher, R, Noakes, TD
British journal of sports medicine. 2004;(4):488-92
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OBJECTIVES To determine whether acute exercise associated muscle cramping (EAMC) in distance runners is related to changes in serum electrolyte concentrations and hydration status. METHODS A cohort of 72 runners participating in an ultra-distance road race was followed up for the development of EAMC. All subjects were weighed before and immediately after the race. Blood samples were taken before the race, immediately after the race, and 60 minutes after the race. Blood samples were analysed for glucose, protein, sodium, potassium, calcium, and magnesium concentrations, as well as serum osmolality, haemoglobin, and packed cell volume. Runners who suffered from acute EAMC during the race formed the cramp group (cramp, n = 21), while runners with no history of EAMC during the race formed the control group (control, n = 22). RESULTS There were no significant differences between the two groups for pre-race or post-race body weight, per cent change in body weight, blood volume, plasma volume, or red cell volume. The immediate post-race serum sodium concentration was significantly lower (p = 0.004) in the cramp group (mean (SD), 139.8 (3.1) mmol/l) than in the control group (142.3 (2.1) mmol/l). The immediate post-race serum magnesium concentration was significantly higher (p = 0.03) in the cramp group (0.73 (0.06) mmol/l) than in the control group (0.67 (0.08) mmol/l). CONCLUSIONS There are no clinically significant alterations in serum electrolyte concentrations and there is no alteration in hydration status in runners with EAMC participating in an ultra-distance race.
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Leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running.
Malm, C, Sjödin, TL, Sjöberg, B, Lenkei, R, Renström, P, Lundberg, IE, Ekblom, B
The Journal of physiology. 2004;(Pt 3):983-1000
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Muscular adaptation to physical exercise has previously been described as a repair process following tissue damage. Recently, evidence has been published to question this hypothesis. The purpose of this study was to investigate inflammatory processes in human skeletal muscle and epimysium after acute physical exercise with large eccentric components. Three groups of subjects (n= 19) performed 45 min treadmill running at either 4 deg (n= 5) or 8 deg (n= 9) downhill or 4 deg uphill (n= 5) and one group served as control (n= 9). One biopsy was taken from each subject 48 h post exercise. Blood samples were taken up to 7 days post exercise. Compared to the control group, none of the markers of inflammation in muscle and epimysium samples was different in any exercised group. Only subjects in the Downhill groups experienced delayed onset of muscle soreness (DOMS) and increased serum creatine kinase activity (CK). The detected levels of immunohistochemical markers for T cells (CD3), granulocytes (CD11b), leukaemia inhibitory factor (LIF) and hypoxia-inducible factor 1beta (HIF-1beta) were greater in epimysium from exercised subjects with DOMS ratings >3 (0-10 scale) compared to exercised subjects without DOMS but not higher than controls. Eccentric physical exercise (downhill running) did not result in skeletal muscle inflammation 48 h post exercise, despite DOMS and increased CK. It is suggested that exercise can induce DOMS by activating inflammatory factors present in the epimysium before exercise. Repeated physical training may alter the content of inflammatory factors in the epimysium and thus reduce DOMS.
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Carbohydrate ingestion influences skeletal muscle cytokine mRNA and plasma cytokine levels after a 3-h run.
Nieman, DC, Davis, JM, Henson, DA, Walberg-Rankin, J, Shute, M, Dumke, CL, Utter, AC, Vinci, DM, Carson, JA, Brown, A, et al
Journal of applied physiology (Bethesda, Md. : 1985). 2003;(5):1917-25
Abstract
Sixteen experienced marathoners ran on treadmills for 3 h at approximately 70% maximal oxygen consumption (Vo(2 max)) on two occasions while receiving 1 l/h carbohydrate (CHO) or placebo (Pla) beverages. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise. Plasma was analyzed for IL-6, IL-10, IL-1 receptor agonist (IL-1ra), IL-8, cortisol, glucose, and insulin. Muscle was analyzed for glycogen content and relative gene expression of 13 cytokines by using real-time quantitative RT-PCR. Plasma glucose and insulin were higher, and cortisol, IL-6, IL-10, and IL-1ra, but not IL-8, were significantly lower postexercise in CHO vs. Pla. Change in muscle glycogen content did not differ between CHO and Pla (P = 0.246). Muscle cytokine mRNA content was detected preexercise for seven cytokines in this order (highest to lowest): IL-15, TNF-alpha, IL-8, IL-1beta, IL-12p35, IL-6, and IFN-gamma. After subjects ran for 3 h, gene expression above prerun levels was measured for five of these cytokines: IL-1beta, IL-6, and IL-8 (large increases), and IL-10 and TNF-alpha (small increases). The increase in mRNA (fold difference from preexercise) was attenuated in CHO (15.9-fold) compared with Pla (35.2-fold) for IL-6 (P = 0.071) and IL-8 (CHO, 7.8-fold; Pla, 23.3-fold; P = 0.063). CHO compared with Pla beverage ingestion attenuates the increase in plasma IL-6, IL-10, and IL-1ra and gene expression for IL-6 and IL-8 in athletes running 3 h at 70% Vo(2 max) despite no differences in muscle glycogen content.
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Effect of the menstrual cycle on performance of intermittent, high-intensity shuttle running in a hot environment.
Sunderland, C, Nevill, M
European journal of applied physiology. 2003;(4-5):345-52
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The present study examined the impact of the menstrual cycle and oral contraceptive use on performance of high-intensity intermittent running in the heat [31.0 (0.2) degrees C; 23.1 (0.9)% relative humidity]. Seven normally menstruating women (NM) and eight oral contraceptive (OC) users participated in the study. Two trials were undertaken near the predicted mid-point of the follicular (FT) and luteal (LT) phases of the menstrual cycle and the equivalent days for the OC users. Basal serum progesterone concentrations were higher during the LT for the NM group [FT: 2.42 (0.28) nmol l(-1) vs LT: 25.96 (11.28) nmol l(-1); P<0.05], but were not different for the OC users [days 1-14: 2.79 (0.38) nmol l(-1) vs days 15-28: 2.61 (0.32) nmol l(-1)]. There were no differences in distance run between menstrual cycle phases or between the normally menstruating and OC groups [NM FT 6257 (1401) m vs LT: 5861 (1035) m]. However, the OC ran further in days 15-28 compared to days 1-14 [OC 1-14: 5481 (612) m vs 15-28: 6615 (893) m, P<0.05]. For the NM, rectal temperature, perceived exertion, estimated SR, serum growth hormone, plasma lactate, ammonia and glucose did not differ between phases of the menstrual cycle. For the OC group, heart rate, perceived exertion, sweat rate, plasma lactate and ammonia did not differ between days 1-14 of OC use and days 15-28. However, rectal temperature was higher ( P<0.05) and growth hormone tended to be higher ( P=0.05) during days 15-28, while plasma glucose was lower ( P<0.05). These results demonstrate that for unacclimatised games players the performance of intermittent, high-intensity shuttle running in the heat is unaffected by menstrual cycle phase but is influenced by OC use.
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Effects of different sodium concentrations in replacement fluids during prolonged exercise in women.
Twerenbold, R, Knechtle, B, Kakebeeke, TH, Eser, P, Müller, G, von Arx, P, Knecht, H
British journal of sports medicine. 2003;(4):300-3; discussion 303
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OBJECTIVE To investigate the effect of different sodium concentrations in replacement fluids on haematological variables and endurance performance during prolonged exercise. METHODS Thirteen female endurance athletes completed three four hour runs on a 400 m track. Environmental conditions differed between the three trials: 5.3 degrees C and snow (trial 1), 19.0 degrees C and sunny weather (trial 2), 13.9 degrees C and precipitation (trial 3). They consumed 1 litre of fluid an hour during the trials with randomised intake of fluids: one trial (H) with high sodium concentration (680 mg/l), one trial (L) with low sodium concentration (410 mg/l), and one trial with only water (W). Before and after the trials, subjects were weighed and blood samples were taken for analysis of [Na(+)](plasma), packed cell volume, and mean corpuscular volume. RESULTS The mean (SD) decrease in [Na(+)](plasma) over the whole trial was significantly (p<0.001) less in trial H (2.5 (2.5) mmol/l) than in trial W (6.2 (2.1) mmol/l). Mild hyponatraemia ([Na(+)](plasma) = 130-135 mmol/l) was observed in only six women (46%) in trial H compared with nine (69%) in trial L, and 12 (92%) in trial W. Two subjects (17%) in trial W developed severe hyponatraemia ([Na(+)](plasma)<130 mmol/l). No significant differences were found in performance or haematological variables with the three different fluids. There was no significant correlation between[Na(+)](plasma) after the run and performance. There was a significant correlation between changes in [Na(+)](plasma) and changes in body weight. CONCLUSIONS Exercise induced hyponatraemia in women is likely to develop from fluid overload during prolonged exercise. This can be minimised by the use of replacement fluids of high sodium concentration. Sodium replacement of at least 680 mg/h is recommended for women in a state of fluid overload during endurance exercise of four hours. However, higher [Na(+)](plasma) after the run and smaller decreases in [Na(+)](plasma) during the trials were no indication of better performance over four hours.