Exercise In Elite Athletes Research Articles

Determination of the Effects of a Series of Ten Whole-Body Cryostimulation Sessions on Physiological Responses to Exercise and Skin Temperature Behavior following Exercise in Elite Athletes.

The present study investigated the effects of a series of 10 whole-body cryostimulation (WBC) sessions (3 min; -110 °C) on physiological and thermal responses to a submaximal exercise test in 17 elite athletes. Participants performed an exercise test twice at similar levels of intensity before and after a series of ten WBC sessions. Before and during the test, each participant's oxygen uptake (VO2), heart rate (HR), internal temperature (Ti), and skin temperature in selected areas of the skin were measured, and the mean arterial pressure (MAP), physiological strain index (PSI), and mean skin temperature (Tsk) were calculated. The results show that during exercise, increases in Ti and the PSI were significantly lower after the WBC sessions, and although there were no significant changes in HR or the MAP, the Tsk was significantly higher. Following exercise, an increase in skin temperature asymmetry over the lower-body muscles was detected. A series of WBC sessions induced a tendency toward a decrease in temperature asymmetry over the thigh muscles. In conclusion, a series of ten WBC sessions does not induce significant modifications in physiological variables but does influence the PSI and Ti during exercise. Moreover, a series of ten WBC sessions influences the distribution of skin temperature and the magnitude of temperature asymmetries in the early phase of recovery.

Development and Validation of Sensitive, Fast and Simple LC-MS/MS Method to Investigate the Association between Adrenocortical Steroidogenesis and the High Intensity Exercise in Elite Athletes.

The very high intensity of exercise accompanied by mental stress triggers adaptive mechanisms associated with adrenocortical steroidogenesis. However, the association between adrenocortical steroidogenesis and the high intensity of exercise in elite athletes is poorly studied. A significant obstacle to solving this complex task is the wide range (4-5 orders) of steroid concentrations in serum and limitations related to the amount of biological samples taken from professional athletes. To solve this task, we have developed and validated a non-trivial approach for targeted serum metabolic profiling based on the use of LC-MS/MS with dual-polarity electrospray ionization. The developed method based on the proposed approach allows for the quantitative determination of 14 stress resistance biomarkers in elite athletes using a small amount of specimen within 8.5 min.

Six Days of Low Carbohydrate, Not Energy Availability, Alters the Iron and Immune Response to Exercise in Elite Athletes.

To quantify the effects of a short-term (6-d) low carbohydrate (CHO) high fat (LCHF), and low energy availability (LEA) diet on immune, inflammatory, and iron-regulatory responses to exercise in endurance athletes. Twenty-eight elite male race walkers completed two 6-d diet/training phases. During phase 1 (Baseline), all athletes consumed a high CHO/energy availability (CON) diet (65% CHO and ~40 kcal·kg-1 fat-free mass (FFM)·d-1). In phase 2 (Adaptation), athletes were allocated to either a CON (n = 10), LCHF (n = 8; <50 g·d-1 CHO and ~40 kcal·kg-1·FFM-1·d-1), or LEA diet (n = 10; 60% CHO and 15 kcal·kg-1·FFM-1·d-1). At the end of each phase, athletes completed a 25-km race walk protocol at ~75% V˙O2max. On each occasion, venous blood was collected before and after exercise for interleukin-6, hepcidin, cortisol, and glucose concentrations, as well as white blood cell counts. The LCHF athletes displayed a greater IL-6 (P = 0.019) and hepcidin (P = 0.011) response to exercise after Adaptation, compared with Baseline. Similarly, postexercise increases in total white blood cell counts (P = 0.026) and cortisol levels (P < 0.001) were larger compared with Baseline after LCHF Adaptation. Decreases in blood glucose concentrations were evident postexercise during Adaptation in LCHF (P = 0.049), whereas no change occurred in CON or LEA (P > 0.05). No differences between CON and LEA were evident for any of the measured biological markers (all P > 0.05). Short-term adherence to a LCHF diet elicited small yet unfavorable iron, immune, and stress responses to exercise. In contrast, no substantial alterations to athlete health were observed when athletes restricted energy availability compared with athletes with adequate energy availability. Therefore, short-term restriction of CHO, rather than energy, may have greater negative impacts on athlete health.

Validity, Reliability, and Sensitivity to Exercise-Induced Fatigue of a Customer-Friendly Device for the Measurement of the Brain's Direct Current Potential.

Valenzuela, PL, Sánchez-Martínez, G, Torrontegi, E, Vázquez-Carrión, J, Montalvo, Z, and Kara, O. Validity, reliability, and sensitivity to exercise-induced fatigue of a customer-friendly device for the measurement of the brain's direct current potential. J Strength Cond Res 36(6): 1605-1609, 2022-This study aimed to determine the validity, reliability, and sensitivity to exercise-induced fatigue of the brain's direct current (DC) potential measured with a commercially available and customer-friendly electroencephalography (EEG) device and Omegawave (OW). The study was composed of 3 different experiments as follows: (a) we compared the DC potential values obtained simultaneously in 31 subjects with both OW and a research-quality EEG system; (b) 3 consecutive DC potential measurements with OW were taken at rest on the same day in 25 subjects for reliability analyses; and (c) sensitivity to fatigue was assessed in 9 elite badminton players through the measurement of the DC potential with OW-as well as other fatigue-related measures (e.g., Hooper's index, heart rate variability, jump ability, and simple and complex reaction times)-24 hours after both a day of rest and of strenuous exercise, which were performed in a crossover and randomized design. The DC potential measured with OW was reliable (intraclass correlation coefficient = 0.97) and significantly correlated to that of EEG (r = 0.55, p = 0.001), although significant differences were observed between systems (p < 0.001). Compared with the rest day, strenuous exercise resulted in an impaired Hooper's index (p = 0.010) and jump ability (p = 0.008), longer simple (p = 0.038) and complex reaction times (p = 0.011), and a trend toward sympathetic dominance (standard deviation of normal to normal R-R intervals, p = 0.042; root mean square of differences between consecutive R-R intervals, p = 0.068). In turn, no significant differences were found between sessions for the DC potential (p = 0.173). In summary, the DC potential measured with OW was reliable and modestly correlated to that measured with EEG, but no differences were observed in response to the delayed fatigue (after 24 hours) elicited by strenuous exercise in elite athletes.

Reference power values for the jump squat exercise in elite athletes: A multicenter study

ABSTRACT The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg−1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg−1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg−1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s−1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.

Does repeated dry sauna bathing change thermoregulation process in elite cross-country skiers?

The aim of this study was to evaluate the influence of a series of ten finnish dry sauna bathing on skin temperature following exercise test for elite cross-country skiers and test, if the regular sauna baths induce any changes in physiological or haematological parameters in elite athletes. Ten elite cross-country skiers (21.7 ± 3.1 years, height: 1.79 ± 0.025 m, body mass: 71.06 ± 4.77 kg) participated in this study. They performed two continuous exercise tests, before and after a series of ten sauna baths. During experiment, the superficial temperature distributions, physiological and haematological parameters were measured. The marked temperature drop was visible in upper body and smaller in lower part of body after exercise test. 10 min after experimental exercise test slow return of the skin temperature to pre-workout values was observed in lower limbs unlike upper part of body. Results of this study indicated that passive induced heat acclimation have a moderate, positive effect (above 2%) on plasma volume and a small impact on physiological and temperature responses to exercise in elite athletes. We conclude that ten finnish dry sauna baths can induce weak changes in the superficial temperature distributions following exercise test, a certain decrease in resting heart rate and small increase in plasma volume in the elite cross-country skiers.

Hydrogen gas: from clinical medicine to an emerging ergogenic molecule for sports athletes 1.

H2 has been clinically demonstrated to provide antioxidant and anti-inflammatory effects, which makes it an attractive agent in exercise medicine. Although exercise provides a multiplicity of benefits including decreased risk of disease, it can also have detrimental effects. For example, chronic high-intensity exercise in elite athletes, or sporadic bouts of exercise (i.e., noxious exercise) in untrained individuals, result in similar pathological factors such as inflammation, oxidation, and cellular damage that arise from and result in disease. Paradoxically, exercise-induced pro-inflammatory cytokines and reactive oxygen species largely mediate the benefits of exercise. Ingestion of conventional antioxidants and anti-inflammatories often impairs exercise-induced training adaptations. Disease and noxious forms of exercise promote redox dysregulation and chronic inflammation, changes that are mitigated by H2 administration. Beneficial exercise and H2 administration promote cytoprotective hormesis, mitochondrial biogenesis, ATP production, increased NAD+/NADH ratio, cytoprotective phase II enzymes, heat-shock proteins, sirtuins, etc. We review the biomedical effects of exercise and those of H2, and we propose that hydrogen may act as an exercise mimetic and redox adaptogen, potentiate the benefits from beneficial exercise, and reduce the harm from noxious exercise. However, more research is warranted to elucidate the potential ergogenic and therapeutic effects of H2 in exercise medicine.

420 - Kinetic of left ventricular function and mechanic during transition from rest to exercise in elite athletes

420 - Kinetic of left ventricular function and mechanic during transition from rest to exercise in elite athletes

Cambios en la respuesta ventilatoria al esfuerzo en deportistas entrenados: efectos beneficiosos sobre la fisiología respiratoria más allá del rendimiento cardiovascular

IntroductionThe beneficial impact of an 8-month competitive season on the ventilatory profile response to exercise in soccer players has never been evaluated. Material and methodsVentilatory profile (evaluated by determining individual tidal volume [VT] relative to minute ventilation [VE] inflection points during exercise) and metabolic responses to incremental exercise were evaluated in 2 professional soccer teams before and after an 8-month competitive season. ResultsNo differences between teams in anthropometric characteristics or in resting cardiopulmonary variables, included oxygen uptake (VO2) and heart rate (HR), before and during the competitive season were found. At iso-speed, there were overall improvements in carbon dioxide output (VCO2), VE/VO2, VE/VCO2, VE and respiratory frequency (fR) during the season. The VT/VE inflection points 1 and 2 occurred with greater exercise time, HR, VO2, VCO2, VE and VT during the competitive season. ConclusionsDespite very high baseline performance and a negligible improvement in VO2, an 8-month competitive season improved ventilatory profile response to exercise in elite athletes.

Changes in Ventilatory Response to Exercise in Trained Athletes: Respiratory Physiological Benefits Beyond Cardiovascular Performance

IntroductionThe beneficial impact of an 8-month competitive season on the ventilatory profile response to exercise in soccer players has never been evaluated. Material and methodsVentilatory profile (evaluated by determining individual tidal volume [VT] relative to minute ventilation [VE] inflection points during exercise) and metabolic responses to incremental exercise were evaluated in 2 professional soccer teams before and after an 8-month competitive season. ResultsNo differences between teams in anthropometric characteristics or in resting cardiopulmonary variables, included oxygen uptake (VO2) and heart rate (HR), before and during the competitive season were found. At iso-speed, there were overall improvements in carbon dioxide output (VCO2), VE/VO2, VE/VCO2, VE and respiratory frequency (fR) during the season. The VT/VE inflection points 1 and 2 occurred with greater exercise time, HR, VO2, VCO2, VE and VT during the competitive season. ConclusionsDespite very high baseline performance and a negligible improvement in VO2, an 8-month competitive season improved ventilatory profile response to exercise in elite athletes.

Local depletion of glycogen with supramaximal exercise in human skeletal muscle fibres.

Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion. Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25±4years, V̇O2 max : 65±4mlkg-1 min-1 ; mean±SD) performed four ∼4min supramaximal sprint time trials (STT 1-4) with 45min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P=0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P=0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P=0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P=0.002]. Furthermore, for each of the subcellular compartments, the depletion of glycogen during STT 1 was associated with the volumes of glycogen before STT 1. In conclusion, the depletion of spatially distinct glycogen compartments differs during supramaximal exercise. Furthermore, the depletion changes with repeated exercise and is fibre type-dependent.

Exercise Intensity and Recovery

Biomarkers of inflammation, muscle damage, and oxidative stress after high-intensity exercise have been described previously; however, further understanding of their role in the postexercise recovery period is necessary. Because these markers have been implicated in cell signaling, they may be specifically related to the training adaptations induced by high-intensity exercise. Thus, a clear model showing their responses to exercise may be useful in characterizing the relative recovery status of an athlete. The purpose of this study was twofold: (a) to investigate the time course of markers of muscle damage and inflammation in the blood from 3 to 72 hours after combined training exercises and (b) to investigate indicators of oxidative stress and damage associated with increased reactive oxygen species production during high-intensity exercise in elite athletes. Nineteen male athletes performed a combination of high-intensity aerobic and anaerobic training exercises. Samples were acquired immediately before and at 3, 6, 12, 24, 48, and 72 hours after exercise. The appearance and clearance of creatine kinase and lactate dehydrogenase in the blood occurred faster than previous studies have reported. The neutrophil/lymphocyte ratio summarizes the mobilization of 2 leukocyte subpopulations in a single marker and may be used to predict the end of the postexercise recovery period. Further analysis of the immune response using serum cytokines indicated that high-intensity exercise performed by highly trained athletes only generated inflammation that was localized to the skeletal muscle. Biomarkers are not a replacement for performance tests, but when used in conjunction, they may offer a better indication of metabolic recovery status. Therefore, the use of biomarkers can improve a coach's ability to assess the recovery period after an exercise session and to establish the intensity of subsequent training sessions.

The Response to and Recovery From Maximum-Strength and -Power Training in Elite Track and Field Athletes.

There is a great deal of research on the responses to resistance training; however, information on the responses to strength and power training conducted by elite strength and power athletes is sparse. To establish the acute and 24-h neuromuscular and kinematic responses to Olympic-style barbell strength and power exercise in elite athletes. Ten elite track and field athletes completed a series of 3 back-squat exercises each consisting of 4 × 5 repetitions. These were done as either strength or power sessions on separate days. Surface electromyography (sEMG), bar velocity, and knee angle were monitored throughout these exercises and maximal voluntary contraction (MVC), jump height, central activation ratio (CAR), and lactate were measured pre, post, and 24 h thereafter. Repetition duration, impulse, and total work were greater (P < .01) during strength sessions, with mean power being greater (P < .01) after the power sessions. Lactate increased (P < .01) after strength but not power sessions. sEMG increased (P < .01) across sets for both sessions, with the strength session increasing at a faster rate (P < .01) and with greater activation (P < .01) by the end of the final set. MVC declined (P < .01) after the strength and not the power session, which remained suppressed (P < .05) 24 h later, whereas CAR and jump height remained unchanged. A greater neuromuscular and metabolic demand after the strength and not power session is evident in elite athletes, which impaired maximal-force production for up to 24 h. This is an important consideration for planning concurrent athlete training.

Adipocytokine responses to acute exercise in athletes with different body fat content and sedentary controls

Introduction: Recent research in the biology of adipose tissue indicates that it is far more than a simply an energy storage organ, and it is in fact an active endocrine organ secreting numerous bioactive mediators, called adipokines, including leptin, adiponectin and visfatin (Galic, 2010). To date, less attention has been focused on the kinetics of adipokines levels during and after high intensity exercise. Several reports pointed at the metabolic role of adipokines during exercise in elite athletes, but the data are currently equivocal (Bouassida et al., 2010; Jurimae et al., 2011). Objectives: The aim of this study was to investigate adipocytokine responses to a single bout acute exercise in elite athletes with low percentage of body fat, elite athletes with a high percentage of body fat and sedentary controls. Methods: Sixteen athletes with low percentage of body fat (volleyball players, low fat athletes group, LFAG), fifteen athletes with high percentage of body fat (water polo players, high fat athletes group, HFAG) and fifteen sedentary subjects participated in this study (age [years] 20±2; 20±2; 20±1, respectively). All subjects were exposed to: anthropometric measurements; exercise test on treadmill in order to examine acute changes of adipocytokines; blood samples were obtained at baseline levels, immediately after the exercise test and 30 minutes after recovery. Separated serum or plasma were used for hormone (leptin, adiponectin and visfatin) ELISA analysis. Results: In athletes in LFAG, baseline leptin concentration was significantly lower, but adiponectin and visfatin concentrations were significantly higher, compared to sedentary controls and athletes in HFAG (p 0.05). Conclusions: Our findings show leptin and visfatin levels, but not adiponectin respond to acute exercise. Acute exercise elicited an inverse visfatin response in athletes in HFAG and controls. Also, these results suggest that leptin is altered after acute exercise only in sedentary individuals.

Damage-associated molecular pattern and innate cytokine release in the airways of competitive swimmers.

Daily intensive exercise by elite athletes can result in exercise-induced asthma especially in elite swimmers and this may be linked to epithelial damage. To study airway epithelial damage and release of damage-associated molecular patterns (DAMPs) after intensive exercise in elite athletes and controls. We recruited competitive swimmers (n=26), competitive indoor athletes (n=13) and controls (n=15) without any history of asthma. Lung function was measured before, immediately after and 24h after a 90-min intensive exercise protocol. Sputum induction was performed at baseline and 24h after exercise. Exercise-induced bronchoconstriction (EIB) was assessed by the eucapnic voluntary hyperventilation test. Baseline sputum uric acid, high mobility group box-1, CXCL8 mRNA, sputum neutrophils and serum Clara cell protein-16 (CC-16) were significantly higher in competitive swimmers compared with controls. Intensive swimming for 90min resulted in an increase of sputum IL-1β, IL-6 and TNF mRNA in competitive swimmers, and of sputum IL-6 mRNA and sputum neutrophils in controls. Although all participants were asymptomatic, seven competitive swimmers, one indoor athlete and one control met the criteria for EIB. Our findings show that the intensive training combined with exposure to by-products of chlorination induces airway epithelial damage in competitive swimmers. This is associated with increased damage-associated molecular patterns, innate cytokine release and neutrophilic airway inflammation.

Neuromuscular response differences to power vs strength back squat exercise in elite athletes.

The study's aim was to establish the neuromuscular responses in elite athletes during and following maximal 'explosive' regular back squat exercise at heavy, moderate, and light loads. Ten elite track and field athletes completed 10 sets of five maximal squat repetitions on three separate days. Knee extension maximal isometric voluntary contraction (MIVC), rate of force development (RFD) and evoked peak twitch force (Pt) assessments were made pre- and post-session. Surface electromyography [root mean square (RMS)] and mechanical measurements were recorded during repetitions. The heavy session resulted in the greatest repetition impulse in comparison to moderate and light sessions (P < 0.001), while the latter showed highest repetition power (P < 0.001). MIVC, RFD, and Pt were significantly reduced post-session (P < 0.01), with greatest reduction observed after the heavy, followed by the moderate and light sessions accordingly. Power significantly reduced during the heavy session only (P < 0.001), and greater increases in RMS occurred during heavy session (P < 0.001), followed by moderate, with no change during light session. In conclusion, this study has shown in elite athletes that the moderate load is optimal for providing a neuromuscular stimulus but with limited fatigue. This type of intervention could be potentially used in the development of both strength and power in elite athletic populations.

ECHOCARDIOGRAPHIC STUDY OF RIGHT VENTRICULAR REMODELING IN TOP-LEVEL GEORGIAN ATHLETES

BackgroundThere are a large number of studies which have focused on left ventricular (LV) structural and functional characteristics, however insufficient data exist concerning right heart response to exercise in elite...

Exercise-Induced Pulmonary Hemorrhage in a Nonathlete: Case Report and Review of Physiology

The integrity of the pulmonary blood-gas barrier is vulnerable to intense exercise in elite athletes, similar to the phenomenon of exercise-induced pulmonary hemorrhage in thoroughbred racehorses. A 50-year-old previously healthy man presented with acute onset shortness of breath, dry cough, and hypoxemia after engaging in an extremely vigorous game of handball. CT scan of the chest showed diffuse patchy air-space disease. Bronchoalveolar lavage revealed diffuse alveolar hemorrhage. Infectious etiologies and bleeding diatheses were excluded by laboratory testing. Serological tests for ANCA-associated vasculitis, lupus, and Goodpasture's disease also were negative. A transthoracic echocardiogram was normal. The patient recovered completely on supportive therapy in less than 72h. This case demonstrates strenuous exercise as a cause of diffuse alveolar hemorrhage in a previously healthy male with no apparent underlying cardiopulmonary disease.

Growth hormone response to the strenuous training in professional skiers has longer recovery time than expected

According to literature, 20–30 minutes recovery period is considered sufficient to normalize growth hormone (GH) levels after exercise stimulation. Aim of our study was to analyze GH response in elite athletes after strenuous training and after 2 hours recovery. We used longitudinal (different years, repeated measures) GH secretion data of 15 skiers (altogether 78 measurements) after very intensive training. Training lasted 3.5 hours with following structure: 0…1 h Lactate (La) &lt;2.5; 1…2h La &lt;3; 2&amp;#8230;2:45 La&lt;4; 2:45…3:30 La&lt;8. Exercise induced very high increase in GH level. Mean basal level of GH was 0.9 mU/L (range 11.2 ), after exercise GH level was 22.1 mU/L (range 103.7). After 2 h recovery, GH level was 3.1 mU/L (range 18.7, p &lt; 005 compared to the basal level). Our results show that depending on intensity and individual variability, GH responses to exercise in elite athletes can be much higher than described in the literature.ConclusionGH level after strenuous training in professional skiers remain still significantly higher after 2‐hour recovery period compared to the pre‐exercise level. The European Regional Development Fund together with the Archimedes Foundation supported this study.

Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes

BackgroundMuscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise.MethodsTen male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured.ResultsAlthough acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise.ConclusionAdequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.