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1.
J Int Soc Sports Nutr ; 18(1): 58, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34419082

RESUMO

BACKGROUND: Exercise increases skeletal muscle reactive oxygen species (ROS) production, which may contribute to the onset of muscular fatigue and impair athletic performance. Mitochondria-targeted antioxidants such as MitoQ, which contains a ubiquinone moiety and is targeted to mitochondria through the addition of a lipophilic triphenylphosphonium cation, are becoming popular amongst active individuals as they are designed to accumulate within mitochondria and may provide targeted protection against exercise-induced oxidative stress. However, the effect of MitoQ supplementation on cycling performance is currently unknown. Here, we investigate whether MitoQ supplementation can improve cycling performance measured as time to complete an 8 km time trial. METHOD: In a randomized, double-blind, placebo-controlled crossover study, 19 middle-aged (age: 44 ± 4 years) recreationally trained (VO2peak: 58.5 ± 6.2 ml·kg- 1·min- 1, distance cycled per week during 6 months prior to study enrollment: 158.3 ± 58.4 km) male cyclists completed 45 min cycling at 70% VO2peak followed by an 8 km time trial after 28 days of supplementation with MitoQ (20 mg·day- 1) and a placebo. Free F2-isoprostanes were measured in plasma samples collected at rest, after 45 min cycling at 70% VO2peak and after completion of the time trial. Respiratory gases and measures of rating of perceived exertion (RPE) were also collected. RESULTS: Mean completion time for the time trial was 1.3% faster with MitoQ (12.91 ± 0.94 min) compared to placebo (13.09 ± 0.95 min, p = 0.04, 95% CI [0.05, 2.64], d = 0.2). There was no difference in RPE during the time trial between conditions (p = 0.82) despite there being a 4.4% increase in average power output during the time trial following MitoQ supplementation compared to placebo (placebo; 270 ± 51 W, MitoQ; 280 ± 53 W, p = 0.04, 95% CI [0.49, 8.22], d = 0.2). Plasma F2-isoprostanes were lower on completion of the time trial following MitoQ supplementation (35.89 ± 13.6 pg·ml- 1) compared to placebo (44.7 ± 16.9 pg·ml- 1 p = 0.03). CONCLUSION: These data suggest that MitoQ supplementation may be an effective nutritional strategy to attenuate exercise-induced increases in oxidative damage to lipids and improve cycling performance.


Assuntos
Antioxidantes/farmacologia , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Mitocôndrias Musculares/efeitos dos fármacos , Compostos Organofosforados/farmacologia , Substâncias para Melhoria do Desempenho/farmacologia , Ubiquinona/análogos & derivados , Adulto , Antioxidantes/metabolismo , Estudos Cross-Over , Método Duplo-Cego , F2-Isoprostanos/sangue , Humanos , Peroxidação de Lipídeos , Masculino , Pessoa de Meia-Idade , Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Compostos Organofosforados/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Consumo de Oxigênio , Substâncias para Melhoria do Desempenho/metabolismo , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Placebos/metabolismo , Placebos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Fenômenos Fisiológicos da Nutrição Esportiva/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Esportiva/fisiologia , Fatores de Tempo , Ubiquinona/metabolismo , Ubiquinona/farmacologia
2.
Nutrients ; 13(8)2021 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-34444703

RESUMO

Supplementation with ß-alanine is becoming a common practice in high-performance athletes. The purpose of the present study was to investigate the effects of a one-week high-dose ß-alanine loading phase employing a sustained-release powder on preserving the time-trial performance capacity of world tour cyclists during overreaching training. Per day, 20 g of sustained-release ß-alanine was administered during one week (7 days) of intensive team training camp in a randomised balanced placebo-controlled parallel trial design, with six participants in each ß-alanine (BA) or placebo (PLA) group. A 10-min time trial (10' TT) was carried out to analyse performance and biochemical variables. Anthropometry, paresthesia, and adverse event data were also collected. Power-based relative training load was quantified. Compared to placebo, the BA improved mean power (6.21%, 37.23 W; 95% CI: 3.98-70.48 W, p = 0.046), distance travelled (2.16%, p = 0.046) and total work (4.85%, p = 0.046) without differences in cadence (p = 0.506) or RPE. Lactate (p = 0.036) and anion gap (p = 0.047) were also higher in the BA group, without differences in pH or Bicarbonate. High daily and single doses were well tolerated. One-week high-dose ß-alanine loading with a sustained-release powder blend can help attenuate 10' TT performance losses of world tour cyclists due to intensive training.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Suplementos Nutricionais , beta-Alanina/administração & dosagem , Adulto , Método Duplo-Cego , Humanos , Masculino , Pós , Adulto Jovem
3.
J Sports Sci Med ; 20(3): 398-403, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34267578

RESUMO

Previous studies reported faster pulmonary oxygen uptake kinetics at the onset of exercise in untrained youth compared with adults. Whether or not these differences are identical for trained groups have not been examined. The purpose of this study was to compare ˙VO2 kinetics of youth and adult cyclists at moderate and heavy-intensity exercise. Thirteen adult (age: 23.2 ± 4.8 years; ˙VO2peak 68.4 ± 6.8 mL·min-1.kg-1) and thirteen youth cyclists (age: 14.3 ± 1.5 years; ˙VO2peak 61.7 ± 4.3 mL·min-1.kg-1) completed a series of 6-min square wave exercises at moderate and heavy-intensity exercise at 90 rev·min-1. A two-way repeated-measure ANOVA was conducted to identify differences between groups and intensities. The time constant, time delay and the mean response time were not significantly different between youth and adult cyclists (p > 0.05). We found significant differences between intensities, with a faster time constant during moderate than heavy-intensity exercise in youth (24.1 ± 7.0 s vs. 31.8 ± 5.6 s; p = 0.004) and adults (22.7 ± 5.6 s vs. 28.6 ± 5.7 s; p < 0.001). The present data suggest that the effect of training history in adult cyclists compensate for the superior primary response of the oxygen uptake kinetics typically seen in youth compared to adults. Furthermore, the ˙VO2 response is dependent of work rate intensity in trained youth and adult cyclists.


Assuntos
Ciclismo/fisiologia , Treino Aeróbico , Consumo de Oxigênio , Adaptação Fisiológica , Adolescente , Adulto , Fatores Etários , Feminino , Humanos , Cinética , Masculino , Adulto Jovem
4.
J Sci Med Sport ; 24(8): 763-767, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34175201

RESUMO

The objective was to compare the efficacy of three different heat acclimation protocols to improve exercise performance in the heat. Thirty four cyclists completed one of three 10-day interventions 1) 50-min cycling per day in 35 °C, 2) 50-min cycling per day wearing thermal clothing, and 3) 50-min cycling wearing thermal clothing plus 25 min hot water immersion per day. Pre- and post-intervention hemoglobin mass, intravascular volumes and core temperature were determined at rest. Heart rate, sweat rate, blood lactate concentration and core temperature were evaluated during 15-min submaximal and 30-min all-out cycling performance conducted in 35.2 ±â€¯0.1 °C and 61 ±â€¯1% relative humidity. There were no significant between-group differences in any of the determined variables. None of the interventions statistically altered any of the parameters investigated as part of the 15-min submaximal trial. However, following the intervention period, heat chamber, thermal clothing and thermal clothing + hot water immersion all improved 30-min all-out average power in the heat (9.5 ±â€¯3.8%, 9.5 ±â€¯3.6 and 9.9 ±â€¯5.2%, respectively, p < 0.001, F = 192.3). At termination of the 30-min all-out test, the increase in blood lactate concentration, rate of perceived exertion and sweat rate were not different between the three interventions. In conclusion, daily training sessions conducted either in ambient 35 °C, while wearing thermal clothing in temperate conditions or while wearing thermal clothing combined with hot water immersion are equally effective for improving exercise performance in the heat.


Assuntos
Aclimatação , Vestuário , Temperatura Alta , Condicionamento Físico Humano/métodos , Condicionamento Físico Humano/fisiologia , Ciclismo/fisiologia , Volume Sanguíneo , Feminino , Frequência Cardíaca , Hematócrito , Hemoglobinometria , Humanos , Imersão , Ácido Láctico/sangue , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Sudorese , Fatores de Tempo , Adulto Jovem
5.
J Int Soc Sports Nutr ; 18(1): 51, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34183020

RESUMO

BACKGROUND: Dietary supplement use among recreational athletes is common, with the intention of reducing inflammation and improving recovery. We aimed to describe the relationship between omega-3 fatty acid supplement use and inflammation induced by strenuous exercise. METHODS: C-reactive protein (CRP) concentrations were measured in 1002 healthy recreational athletes before and 24 h after a 91-km bicycle race. The use of omega-3 fatty acid supplements was reported in 856 out of 1002 recreational athletes, and the association between supplement use and the exercise-induced CRP response was assessed. RESULTS: Two hundred seventy-four subjects reported regular use of omega-3 fatty acid supplements. One hundred seventy-three of these used cod liver oil (CLO). Regular users of omega-3 fatty acid supplements had significantly lower basal and exercise-induced CRP levels as compared to non-users (n = 348, p < 0.001). Compared to non-users, regular users had a 27% (95% confidence interval (CI): 14-40) reduction in Ln CRP response (unadjusted model, p < 0.001) and 16% (95% CI: 5-28, p = 0.006) reduction after adjusting for age, sex, race duration, body mass index, delta creatine kinase, MET hours per week, resting heart rate and higher education. CLO was the primary driver of this response with a 34% (95% CI: 19-49) reduction (unadjusted model, p < 0.001) compared to non-users. Corresponding numbers in the adjusted model were 24% (95% CI: 11-38, p < 0.001). CONCLUSION: Basal CRP levels were reduced, and the exercise-induced CRP response was attenuated in healthy recreational cyclists who used omega-3 fatty acid supplements regularly. This effect was only present in regular users of CLO. TRIAL REGISTRATION: NCT02166216 , registered June 18, 2014 - Retrospectively registered.


Assuntos
Proteína C-Reativa/análise , Óleo de Fígado de Bacalhau/administração & dosagem , Exercício Físico/fisiologia , Vitaminas/administração & dosagem , Adulto , Ciclismo/fisiologia , Intervalos de Confiança , Creatina Quinase/sangue , Ácidos Graxos Ômega-3/administração & dosagem , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
6.
Int J Sport Nutr Exerc Metab ; 31(4): 305-313, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34098531

RESUMO

Currently, little is known about the extent of interindividual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high-intensity cycling capacity test (CCT110%) were meta-analyzed. Changes in time to exhaustion (TTE) and muscle carnosine were the primary and secondary outcomes. Multilevel distributional Bayesian models were used to estimate the mean and SD of BA and placebo group change scores. The relative sizes of group SDs were used to infer whether observed variation in change scores were due to intervention or non-intervention-related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7, 95% credible interval [CrI] [1.3, 14.3] s) and muscle carnosine (18.1, 95% CrI [14.5, 21.9] mmol/kg DM). A large intervention response variation was identified for muscle carnosine (σIR = 5.8, 95% CrI [4.2, 7.4] mmol/kg DM) while equivalent change score SDs were shown for TTE in both the placebo (16.1, 95% CrI [13.0, 21.3] s) and BA (15.9, 95% CrI [13.0, 20.0] s) conditions, with the probability that SD was greater in placebo being 0.64. In conclusion, the similarity in observed change score SDs between groups for TTE indicates the source of variation is common to both groups, and therefore unrelated to the supplement itself, likely originating instead from external factors such as nutritional intake, sleep patterns, or training status.


Assuntos
Ciclismo/fisiologia , Carnosina/metabolismo , Suplementos Nutricionais , Tolerância ao Exercício/fisiologia , Músculo Esquelético/metabolismo , beta-Alanina/administração & dosagem , Teorema de Bayes , Viés , Método Duplo-Cego , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Fenômenos Fisiológicos da Nutrição Esportiva , Fatores de Tempo
7.
Med Sci Sports Exerc ; 53(7): 1417-1424, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34127635

RESUMO

PURPOSE: Executive dysfunction has been widely reported in children with autism spectrum disorder (ASD). Although studies have clearly documented the cognitive benefits of physical exercise on cognition in children, similar studies in children with ASD are scarce. The purpose of this study was to compare the effect of cognitively engaging exercise and noncognitively engaging exercise on executive function in children with ASD. METHODS: Sixty-two children diagnosed with ASD (50 males and 12 females, Mage = 9.89 ± 1.53 yr, Mheight = 1.43 ± 0.15 m, and Mweight = 44.69 ± 11.96 kg) were randomly assigned into three groups: learning to ride a bicycle (n = 22), stationary cycling (n = 20), and control (n = 20). Four executive function components (planning, working memory, flexibility, and inhibition) were assessed. RESULTS: Results revealed significant improvements in all executive function components in the learning to ride a bicycle group (Ps < 0.05) but not in the other two groups after controlling for age and IQ. CONCLUSION: Our findings highlight the value of cognitive engagement in exercise programs designed to improve cognition in children with ASD.


Assuntos
Transtorno do Espectro Autista/terapia , Ciclismo/fisiologia , Disfunção Cognitiva/terapia , Função Executiva/fisiologia , Exercício Físico/fisiologia , Memória de Curto Prazo/fisiologia , Criança , Feminino , Humanos , Masculino
8.
J Sci Med Sport ; 24(8): 800-805, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34020886

RESUMO

OBJECTIVES: To investigate the effects of pre- and per-cooling interventions on subsequent 15-min time-trial (TT) cycling performance in the heat. DESIGN: Randomized cross-over design. METHODS: Nine male athletes completed four experimental trials in the heat (40 °C, 50% rh): no-cooling (CON); warm-up per-cooling (PER: neck-cooling collar applied during the preload); pre-cooling (PRE: 30 min of cold water (22 °C) immersion [CWI]); and pre- and per-cooling combined (PRE + PER). In each trial, participants completed a 45-min preload exercise (50% V̇O2peak), followed by a 15-min TT. Physiological (rectal [Tre], skin [Tsk], and neck [Tneck] temperature, and heart rate [HR]) and perceptual data (ratings of perceived exertion [RPE], thermal comfort [TC] and thermal sensation [TS]) were measured throughout. RESULTS: Tre and Tsk were lower in PRE and PRE + PER at the start of the preload (p < 0.001). Tre remained lower throughout the preload following CWI although these differences were no longer present at the start of the TT (p = 0.22). Tneck was lowered throughout in PER and PRE + PER (p < 0.001). No other physiological or perceptual differences were observed at the start or end of the preload or TT. Participants covered a similar TT distance in all trials (15.7-15.9 km, p = 0.77). CONCLUSIONS: Pre-cooling induced thermoregulatory benefits for ~45 min and perceptual benefits for the same duration when supplemented with per-cooling. Neck per-cooling offered no such benefits when used in isolation. Neither pre- nor per-cooling, in isolation or combination, improved subsequent 15-min cycling time-trial performance in well-trained participants in the heat (40 °C).


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Crioterapia/métodos , Temperatura Alta , Adulto , Temperatura Corporal , Vestuário , Estudos Cross-Over , Frequência Cardíaca , Resposta ao Choque Térmico , Humanos , Imersão , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Sensação Térmica , Fatores de Tempo , Adulto Jovem
9.
J Int Soc Sports Nutr ; 18(1): 35, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33971893

RESUMO

BACKGROUND: Being a major cardiovascular risk factor, dyslipidemia is a critical problem in public health. Recommendations in performing regular physical exercise are important to prevent dyslipidemia. METHODS: Based on a discovery cohort with 27,735 subjects and a replication cohort with 67,512 subjects, we evaluated the associations of regularly performing 23 exercises with 4 dyslipidemia indices measured from serum, including triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and TG/HDL-C ratio. Regular exercise was defined as performing 30 min of "exercise" three times a week. "Exercise" includes leisure-time activities such as jogging, swimming, etc. Sex, age, body mass index, alcohol drinking, cigarette smoking, and education level were adjusted in all statistical analyses. RESULTS: Among the 23 exercises, only jogging was associated with a decreased level of TG (95% confidence interval [C.I.] = 5.9-14.5 mg/dL) and TG/HDL-C ratio (95% C.I. = 0.22-0.49). A total of 5 exercises were associated with an increased level of HDL-C, including jogging (95% C.I. = 2.1-3.3 mg/dL), swimming (95% C.I. = 1.6-3.3 mg/dL), dance dance revolution (95% C.I. = 1.5-3.4 mg/dL), international standard dancing (95% C.I. = 1.0-2.7 mg/dL), and cycling (95% C.I. = 0.6-1.8 mg/dL). These significant findings were further well replicated in the cohort of 67,512 subjects. CONCLUSION: Regular jogging was not only associated with an increased level of HDL-C, but also the only one exercise associated with a decreased level of TG and TG/HDL-C ratio. Nonetheless, jogging may be difficult to engage in for subjects with limited exercise capacity. We here found that swimming, dancing, and cycling are also significantly associated with an increased level of HDL-C. People who are seeking exercise to improve their lipoprotein-lipid profiles can have other choices now.


Assuntos
HDL-Colesterol/sangue , LDL-Colesterol/sangue , Exercício Físico/fisiologia , Triglicerídeos/sangue , Adulto , Idoso , Ciclismo/fisiologia , Dança/fisiologia , Dislipidemias/prevenção & controle , Feminino , Humanos , Corrida Moderada/fisiologia , Masculino , Pessoa de Meia-Idade , Natação/fisiologia
10.
J Int Soc Sports Nutr ; 18(1): 36, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001168

RESUMO

BACKGROUND: Elite athletes may suffer from impaired immune function and gastro-intestinal (GI) symptoms, which may affect their health and may impede their performance. These symptoms may be reduced by multi-strain probiotic supplementation. Therefore, the aim of the current study is to examine the effects of probiotic supplementation on aerobic fitness characteristics, inflammatory markers and incidence and severity of GI symptoms in elite cyclists. METHODS: Twenty-seven male cyclists, ranked elite or category 1 level competitions, were randomly assigned to a multi-strain probiotic-supplemented group (E, n = 11) or placebo group (C, n = 16). All participants visited the laboratory at the beginning of the study and following 90 d of supplementation/placebo. Prior to testing, all participants completed a GI symptoms questionnaire and underwent physical and medical examination, and anthropometric measurements. Venous blood was drawn for inflammatory markers analysis. The cyclists then underwent maximal oxygen consumption (VO2max) test and time-to-fatigue (TTF) test at 85 % of maximal power, 3 h following the VO2max test. All testing procedures were repeated after 90 d of probiotic / placebo treatment (double blind design). RESULTS: Lower incidence of nausea, belching, and vomiting (P < 0.05) at rest, and decreased incidence of GI symptoms during training were found in E group vs. C Group, respectively (∆GI -0.27 ± 0.47 % vs. 0.08 ± 0.29 %, P = 0.03), no significant changes were observed in the incidence of total overall GI symptoms (∆GI -5.6 ± 14.7 % vs. 2.6 ± 11.6 %, P = 0.602) Mean rate of perceived exertion (RPE) values during the TTF were lower in E group (∆RPE: -0.3 ± 0.9 vs. 0.8 ± 1.5, P = 0.04). No significant changes were measured between and within groups in VO2max and TTF values, mean levels of C-reactive protein (CRP), IL-6-and tumor necrosis factor alpha (TNFα) values following treatment. CONCLUSIONS: Probiotics supplementation may have beneficial effects on GI symptoms in elite cyclists. Future studies, using higher doses and during different training seasons, might help understanding the effects of probiotic supplementation on elite athletes' health and performance. TRIAL REGISTRATION: NIH clinicaltrial.gov #NCT02756221 Registered 25 April 2016.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Suplementos Nutricionais , Gastroenteropatias/prevenção & controle , Inflamação/prevenção & controle , Probióticos/administração & dosagem , Adulto , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , Método Duplo-Cego , Gastroenteropatias/fisiopatologia , Humanos , Inflamação/fisiopatologia , Interleucina-6/sangue , Masculino , Fadiga Muscular , Consumo de Oxigênio , Condicionamento Físico Humano/fisiologia , Fator de Necrose Tumoral alfa/sangue , Adulto Jovem
11.
J Sports Sci ; 39(18): 2080-2086, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33906585

RESUMO

Athletes physically overload to improve performance. Unbalanced stress/recovery may induce overtraining, which is difficult to diagnosis as no diagnostic marker exists. Hormonal responses to a 55/80 cycle (30-min of alternating blocks of 1-min at 55% and 4-min at 80% maximum work rate) may highlight early-stage overtraining (overreaching), as blunted cortisol and testosterone responses to 55/80 follows intensified training. However, the reliability of hormonal responses to 55/80 when not overreached is unknown. Therefore, reported blunted hormonal responses could be due to inconsistent cortisol and testosterone responses to 55/80. Participants (n = 23) completed three 55/80 bouts, >7 days apart, with no exercise 24 h pre-trials. Pre-exercise urine osmolality and stress questionnaire responses were measured. Pre, post, and 30-min post-exercise saliva samples were collected for cortisol and testosterone assessment. Salivary cortisol and testosterone responses, osmolality and well-being were not different between trials. Salivary cortisol and testosterone elevated from pre- to post-exercise [by 4.2 nmol.L-1 (cortisol) and 307 pmol.L-1 (testosterone)], and 30 min post-exercise [by 160 pmol.L-1 (testosterone) only]. Intraclass correlation coefficients for pre to peak post-exercise cortisol (0.89; good) and testosterone (0.53; moderate) were calculated. This demonstrates that 55/80 induces reliable elevations of salivary cortisol and testosterone when in a healthy state.


Assuntos
Ciclismo/fisiologia , Hidrocortisona/metabolismo , Resistência Física/fisiologia , Testosterona/metabolismo , Adolescente , Adulto , Teste de Esforço , Voluntários Saudáveis , Humanos , Masculino , Reprodutibilidade dos Testes , Saliva/química , Inquéritos e Questionários , Adulto Jovem
12.
Nutrients ; 13(4)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804967

RESUMO

BACKGROUND: The aim of this study was to investigate energy expenditure, food intake and appetite feelings in response to water- vs. land-based cycling exercises in healthy young women. METHODS: Anthropometric measurements and body composition were assessed among 20 women who performed four experimental sessions in a randomized order: (i) a rest condition (CONT); (ii) a 30-min aqua-cycling exercise session (WAT), (iii) a 30-min land-cycling exercise session at the same rpm (LAND), (iv) a land-cycling session at the same heart rate and isoenergetic to WAT (LAND-Iso). Energy expenditure and substrate oxidation were measured by indirect calorimetry; ad libitum energy intake during subsequent lunch was assessed with appetite feelings recorded at regular intervals. RESULTS: Energy expenditure was higher during the 30-min WAT than during CONT and LAND (p < 0.001). Carbohydrate oxidation was higher in the WAT session compared to CONT and LAND (p < 0.05). LAND-Iso duration was significantly increased (+14 min) to reach the same energy expenditure as in the WAT condition (p < 0.05). There was no differences in food intake between sessions. CONCLUSION: While further studies are needed to optimize the chronic energetic effects of aqua-cycling, the present study suggests that this exercise modality could represent an efficient strategy to induce acute energy deficit.


Assuntos
Apetite/fisiologia , Ciclismo/fisiologia , Ingestão de Energia/fisiologia , Natação/fisiologia , Adulto , Calorimetria Indireta , Metabolismo Energético/fisiologia , Feminino , Humanos , Valores de Referência
13.
Nutrients ; 13(3)2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33800770

RESUMO

This single-arm interventional study examined the effect of a 4-week ketogenic diet (KD) on aerobic capacity and discipline-specific performance in female (n = 11) and male (n = 11) CrossFit-trained athletes. The participants performed incremental cycling (ICT) and Fight Gone Bad (FGB) tests after consuming a customary diet and a KD. Pre- and post-ICT exercise blood samples were also analysed. Consuming a KD had a slight impact on aerobic capacity and no relevant effect on CrossFit-specific performance. In females, consuming a KD led to an 10.4% decrease in peak oxygen uptake during the ICT (p = 0.027) and resulted in certain alterations in haematological parameters (haemoglobin (HGB), mean corpuscular HGB, and mean corpuscular HGB concentration). Furthermore, in males, alanine aminotransferase activity increased with a simultaneous improvement in the post-ICT blood acid-base balance after consuming a KD. The pre-exercise bilirubin concentration was also elevated in the entire group after consuming a KD. In conclusion, female CrossFit-trained athletes seem to be prone to aerobic performance decrements and increased risk of developing haematological disturbances when consuming a KD. In males who consumed a KD, there was an undesirable alanine aminotransferase elevation and a small tendency towards improved acid-base status. Moreover, consuming a KD had no effect on discipline-specific performance in CrossFit-trained athletes.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Dieta Cetogênica/efeitos adversos , Treinamento Intervalado de Alta Intensidade , Equilíbrio Ácido-Base , Adolescente , Adulto , Alanina Transaminase/sangue , Bilirrubina/sangue , Índices de Eritrócitos/fisiologia , Feminino , Hemoglobinas/metabolismo , Humanos , Masculino , Consumo de Oxigênio , Fatores Sexuais , Adulto Jovem
14.
Nutrients ; 13(3)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806669

RESUMO

Implementing permissive dehydration (DEH) during short-term heat acclimation (HA) may accelerate adaptations to the heat. However, HA with DEH may augment risk for acute kidney injury (AKI). This study investigated the effect of HA with permissive DEH on time-trial performance and markers of AKI. Fourteen moderately trained men (age and VO2max = 25 ± 0.5 yr and 51.6 ± 1.8 mL.kg-1.min-1) were randomly assigned to DEH or euhydration (EUH). Time-trial performance and VO2max were assessed in a temperate environment before and after 7 d of HA. Heat acclimation consisted of 90 min of cycling in an environmental chamber (40 °C, 35% RH). Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) were assessed pre- and post-exercise on day 1 and day 7 of HA. Following HA, VO2max did not change in either group (p = 0.099); however, time-trial performance significantly improved (3%, p < 0.01) with no difference between groups (p = 0.485). Compared to pre-exercise, NGAL was not significantly different following day 1 and 7 of HA (p = 0.113) with no difference between groups (p = 0.667). There was a significant increase in KIM-1 following day 1 and 7 of HA (p = 0.002) with no difference between groups (p = 0.307). Heat acclimation paired with permissive DEH does not amplify improvements in VO2max or time-trial performance in a temperate environment versus EUH and does not increase markers of AKI.


Assuntos
Aclimatação/fisiologia , Injúria Renal Aguda/etiologia , Desidratação/fisiopatologia , Exercício Físico/fisiologia , Temperatura Alta/efeitos adversos , Adulto , Ciclismo/fisiologia , Biomarcadores/sangue , Desidratação/complicações , Teste de Esforço , Receptor Celular 1 do Vírus da Hepatite A/sangue , Humanos , Lipocalina-2/sangue , Masculino , Consumo de Oxigênio , Termotolerância
15.
Nutrients ; 13(4)2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33919779

RESUMO

Nutritional intake can influence exercise metabolism and performance, but there is a lack of research comparing protein-rich pre-exercise meals with endurance exercise performed both in the fasted state and following a carbohydrate-rich breakfast. The purpose of this study was to determine the effects of three pre-exercise nutrition strategies on metabolism and exercise capacity during cycling. On three occasions, seventeen trained male cyclists (VO2peak 62.2 ± 5.8 mL·kg-1·min-1, 31.2 ± 12.4 years, 74.8 ± 9.6 kg) performed twenty minutes of submaximal cycling (4 × 5 min stages at 60%, 80%, and 100% of ventilatory threshold (VT), and 20% of the difference between power at the VT and peak power), followed by 3 × 3 min intervals at 80% peak aerobic power and 3 × 3 min intervals at maximal effort, 30 min after consuming a carbohydrate-rich meal (CARB; 1 g/kg CHO), a protein-rich meal (PROTEIN; 0.45 g/kg protein + 0.24 g/kg fat), or water (FASTED), in a randomized and counter-balanced order. Fat oxidation was lower for CARB compared with FASTED at and below the VT, and compared with PROTEIN at 60% VT. There were no differences between trials for average power during high-intensity intervals (367 ± 51 W, p = 0.516). Oxidative stress (F2-Isoprostanes), perceived exertion, and hunger were not different between trials. Overall, exercising in the overnight-fasted state increased fat oxidation during submaximal exercise compared with exercise following a CHO-rich breakfast, and pre-exercise protein ingestion allowed similarly high levels of fat oxidation. There were no differences in perceived exertion, hunger, or performance, and we provide novel data showing no influence of pre-exercise nutrition ingestion on exercise-induced oxidative stress.


Assuntos
Ciclismo/fisiologia , Jejum/fisiologia , Refeições/fisiologia , Estresse Oxidativo/fisiologia , Adolescente , Adulto , Atletas , Desempenho Atlético/fisiologia , Carboidratos da Dieta/administração & dosagem , Proteínas na Dieta/administração & dosagem , Humanos , Fome/fisiologia , Metabolismo dos Lipídeos/fisiologia , Masculino , Oxirredução , Resistência Física/fisiologia , Esforço Físico/fisiologia , Adulto Jovem
16.
Am J Physiol Regul Integr Comp Physiol ; 320(6): R812-R823, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33787348

RESUMO

The present study analyzed the effects of local ischemia during endurance exercise on neuromuscular fatigue (NMF). Nine cyclists performed, in a counterbalanced order, two separate 4-km cycling time trials (TT) with (ISCH) or without (CONTR) induced local ischemia. NMF was characterized by using isometric maximal voluntary contractions (IMVC), whereas central [voluntary activation (VA)] and peripheral fatigue [peak torque of potentiated twitch (TwPt)] of knee extensors were evaluated using electrically evoked contractions performed before (PRE) and 1 min after (POST) the TT. Electromyographic activity (EMG), power output (PO), oxygen uptake (V̇o2), and rating of perceived exertion (RPE) were also recorded. The decrease in IMVC (-15 ± 9% vs. -10 ± 8%, P = 0.66), VA (-4 ± 3% vs. -3 ± 3%, P = 0.46), and TwPt (-16 ± 7% vs. -19 ± 14%, P = 0.67) was similar in ISCH and CONTR. Endurance performance was drastically reduced in ISCH condition (512 ± 29 s) compared with CONTR (386 ± 17 s) (P < 0.001), which was accompanied by lower EMG, PO, and V̇o2 responses (all P < 0.05). RPE was greater in ISCH compared with CONTR (P < 0.05), but the rate of change was similar throughout the TT (8.19 ± 2.59 vs. 7.81 ± 2.01 RPE.% of total time-1, P > 0.05). These results indicate that similar end-exercise NMF levels were accompanied by impaired endurance performance in ISCH compared with CONTR. These novel findings suggest that the local reduced oxygen availability affected the afferent feedback signals to the central nervous system, ultimately increasing perceived effort and reducing muscle activity and exercise intensity to avoid surpassing a sensory tolerance limit before the finish line.


Assuntos
Desempenho Atlético/fisiologia , Isquemia/fisiopatologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Adulto , Ciclismo/fisiologia , Exercício Físico/fisiologia , Humanos , Contração Isométrica/fisiologia , Articulação do Joelho/fisiologia , Articulação do Joelho/fisiopatologia , Masculino , Músculo Esquelético/fisiologia
17.
J Sports Sci Med ; 20(1): 170-178, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33708000

RESUMO

Fat oxidation during exercise is associated with cardio-metabolic benefits, but the extent of which whole-body exercise modality elicits the greatest fat oxidation remains unclear. We investigated the effects of treadmill, elliptical and rowing exercise on fat oxidation in healthy individuals. Nine healthy males participated in three, peak oxygen consumption tests, on a treadmill, elliptical and rowing ergometer. Indirect calorimetry was used to assess maximal oxygen consumption (V̇O2peak), maximal fat oxidation (MFO) rates, and the exercise intensity MFO occurred (Fatmax). Mixed venous blood was collected to assess lactate and blood gases concentrations. While V̇O2peak was similar between exercise modalities, MFO rates were higher on the treadmill (mean ± SD; 0.61 ± 0.06 g·min-1) compared to both the elliptical (0.41 ± 0.08 g·min-1, p = 0.022) and the rower (0.40 ± 0.08 g·min-1, p = 0.017). Fatmax values were also significantly higher on the treadmill (56.0 ± 6.2 %V̇O2peak) compared to both the elliptical (36.8 ± 5.4 %V̇O2peak, p = 0.049) and rower (31.6 ± 5.0 %V̇O2peak, p = 0.021). Post-exercise blood lactate concentrations were also significantly lower following treadmill exercise (p = 0.021). Exercising on a treadmill maximizes fat oxidation to a greater extent than elliptical and rowing exercises, and remains an important exercise modality to improve fat oxidation, and consequently, cardio-metabolic health.


Assuntos
Ciclismo/fisiologia , Tolerância ao Exercício/fisiologia , Metabolismo dos Lipídeos , Consumo de Oxigênio/fisiologia , Corrida/fisiologia , Esportes Aquáticos/fisiologia , Glicemia/análise , Glicemia/metabolismo , Testes Respiratórios , Calorimetria Indireta , Teste de Esforço/instrumentação , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Oxirredução , Adulto Jovem
18.
Scand J Med Sci Sports ; 31(7): 1440-1449, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33730398

RESUMO

The purpose of the study was to determine if concurrent training (endurance and resistance in a single session) elicits leg muscular adaptations beyond the ones obtained by endurance training alone in sedentary individuals with metabolic syndrome (MetS). Sixty-six MetS individuals (37% women, age 56 ± 7 years, BMI 32 ± 5 kg m-2 and 3.8 ± 0.8 MetS factors) were randomized to undergo one of the following 16-week isocaloric exercise programs: (i) 4 + 1 bouts of 4 min at 90% of HRMAX of intense aerobic cycling (IAC + IAC group; n = 33), (ii) 4 IAC bouts followed by 3 sets of 12 repetitions of 3 lower-limb free-weight exercises (IAC + RT group; n = 33). We measured the effects of training on maximal cycling power, leg press maximum strength (1RM), countermovement jump height (CMJ), and mean propulsive velocity (MPV) at workloads ranging from 10% to 100% of baseline 1RM leg press. After intervention, MetS components (Z-score) improved similarly in both groups (p = 0.002). Likewise, maximal cycling power during a ramp test improved similarly in both groups (time effect p < 0.001). However, leg press 1RM improved more in IAC + RT than in IAC + IAC (47 ± 5 vs 13 ± 5 kg, respectively, interaction p < 0.001). CMJ only improved with IAC + RT (0.8 ± 0.2 cm, p = 0.001). Leg press MPV at heavy loads (ie, 80%-100% 1RM) improved more with concurrent training (0.12 ± 0.01 vs 0.06 ± 0.02 m s-1 , interaction p = 0.013). In conclusion, in unconditioned MetS individuals, intense aerobic cycling alone improves leg muscle performance. However, substituting 20% of intense aerobic cycling by resistance training further improves 1RM leg press, MPV at high loads, and jumping ability while providing similar improvement in MetS components.


Assuntos
Adaptação Fisiológica , Treino Aeróbico/métodos , Exercício Físico/fisiologia , Síndrome Metabólica/fisiopatologia , Músculo Esquelético/fisiologia , Treinamento de Força/métodos , Ciclismo/fisiologia , Composição Corporal , Feminino , Humanos , Perna (Membro)/fisiologia , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Comportamento Sedentário , Fatores de Tempo , Circunferência da Cintura , Carga de Trabalho
19.
J Sport Health Sci ; 10(1): 99-106, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33518019

RESUMO

BACKGROUND: One-legged pedaling is of interest to elite cyclists and clinicians. However, muscular usage in 1-legged vs. 2-legged pedaling is not fully understood. Thus, the study was aimed to examine changes in leg muscle activation patterns between 2-legged and 1-legged pedaling. METHODS: Fifteen healthy young recreational cyclists performed both 1-legged and 2-legged pedaling trials at about 30 Watt per leg. Surface electromyography electrodes were placed on 10 major muscles of the left leg. Linear envelope electromyography data were integrated to quantify muscle activities for each crank cycle quadrant to evaluate muscle activation changes. RESULTS: Overall, the prescribed constant power requirements led to reduced downstroke crank torque and extension-related muscle activities (vastus lateralis, vastus medialis, and soleus) in 1-legged pedaling. Flexion-related muscle activities (biceps femoris long head, semitendinosus, lateral gastrocnemius, medial gastrocnemius, tensor fasciae latae, and tibialis anterior) in the upstroke phase increased to compensate for the absence of contralateral leg crank torque. During the upstroke, simultaneous increases were seen in the hamstrings and uni-articular knee extensors, and in the ankle plantarflexors and dorsiflexors. At the top of the crank cycle, greater hip flexor activity stabilized the pelvis. CONCLUSION: The observed changes in muscle activities are due to a variety of changes in mechanical aspects of the pedaling motion when pedaling with only 1 leg, including altered crank torque patterns without the contralateral leg, reduced pelvis stability, and increased knee and ankle stiffness during the upstroke.


Assuntos
Ciclismo/fisiologia , Perna (Membro)/fisiologia , Músculo Esquelético/fisiologia , Adulto , Fenômenos Biomecânicos/fisiologia , Análise de Dados , Coleta de Dados , Eletrodos , Eletromiografia/métodos , Feminino , Músculos Isquiossurais/fisiologia , Humanos , Masculino , Fenômenos Fisiológicos Musculoesqueléticos , Músculo Quadríceps/fisiologia , Torque
20.
J Sci Med Sport ; 24(7): 689-695, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33632661

RESUMO

OBJECTIVES: Regular physical exercise is known to protect endothelial integrity. It has been proposed that acute exercise-induced changes of the (anti-)oxidative system influence early (glycocalyx shedding) and sustained endothelial activation (shedding of endothelial cells, ECs) as well as endothelial-cell repair by circulating hematopoietic stem and progenitor cells (HPCs). However, results are not conclusive and data in trained participants performing different exercise modalities is lacking. DESIGN: Eighteen healthy, well-trained participants (9 runners, 9 cyclists; age: 29.7 ±â€¯4.2 yrs) performed a strenuous acute exercise session consisting of 4 bouts of 4-min high-intensity with decreasing power profile and 3-min low-intensity in-between. METHODS: Average power/speed of intense phases was 85% of the peak achieved in a previous incremental test. Before and shortly after exercise, total oxidative and antioxidative capacities (TAC), shedding of syndecan-1, heparan sulfate, hyaluronan, ECs, and circulating HPCs were investigated. RESULTS: TAC decreased from 1.81 ±â€¯0.42 nmol/L to 1.47 ±â€¯0.23 nmol/L post-exercise (p = 0.010) only in runners. Exercise-induced early and sustained endothelial activation were enhanced post-exercise- syndecan-1: 103.2 ±â€¯63.3 ng/mL to 111.3 ±â€¯71.3 ng/mL, heparan sulfate: from 2637.9 ±â€¯800.1 ng/mL to 3197.1 ±â€¯1416.3 ng/mL, both p < 0.05; hyaluronan: 84.3 ±â€¯21.8 ng/mL to 121.4 ±â€¯29.4 ng/mL, ECs: from 6.6 ±â€¯4.5 cells/µL to 9.5 ±â€¯6.2 cells/µL, both p < 0.01; results were not different between exercise modalities and negatively related to TAC concentrations post-exercise. HPC proportions and self-renewal ability were negatively, while EC concentrations were positively associated with circulating hyaluronan concentrations. CONCLUSIONS: These results highlight the importance of the antioxidative system to prevent the endothelium from acute exercise-induced vascular injury - independent of exercise modality - in well-trained participants. Endothelial-cell repair is associated with hyluronan signaling, possibly a similar mechanism as in wound repair.


Assuntos
Antioxidantes/metabolismo , Ciclismo/fisiologia , Células Endoteliais/metabolismo , Glicocálix/metabolismo , Corrida/fisiologia , Adulto , Células-Tronco Hematopoéticas/metabolismo , Heparitina Sulfato/sangue , Humanos , Ácido Hialurônico/sangue , Masculino , Estresse Oxidativo , Sindecana-1/sangue
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