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1.
Chin J Physiol ; 62(5): 226-230, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31670287

RESUMEN

Angiotensin-(1-7) (Ang-[1-7]) can modulate glucose metabolism and protect against muscular damage. The aim of this study was to investigate the influence of lifetime increase of circulating levels of Ang-(1-7) at exhaustive swimming exercise (ESE). Sprague-Dawley (SD) and transgenic rats TGR(A1-7)3292 (TR) which overproduce Ang-(1-7) (2.5-fold increase) were submitted to ESE. The data showed no differences in time to exhaustion (SD: 4.90 ± 1.37 h vs. TR: 5.15 ± 1.15 h), creatine kinase, and transforming growth factor beta (TGF-ß). Lactate dehydrogenase (SD: 219.9 ± 12.04 U/L vs. TR: 143.9 ± 35.21 U/L) and α-actinin (SD: 336.7 ± 104.5 U/L vs. TR: 224.6 ± 82.45 U/L) values were significantly lower in TR. There was a significant decrease in the range of blood glucose levels (SD: -41.4 ± 28.32 mg/dl vs. TR: -13.08 ± 39.63 mg/dl) in SD rats. Muscle (SD: 0.06 ± 0.02 mg/g vs. TR: 0.13 ± 0.01 mg/g) and hepatic glycogen (SD: 0.66 ± 0.36 mg/g vs. TG: 2.24 ± 1.85 mg/g) in TR were higher. The TR presented attenuation of the increase in skeletal muscle damage biomarkers and of the changes in glucose metabolism after ESE.


Asunto(s)
Músculo Esquelético , Angiotensina I , Animales , Biomarcadores , Fragmentos de Péptidos , Ratas , Ratas Sprague-Dawley
3.
J Strength Cond Res ; 33(12): 3414-3422, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28767483

RESUMEN

Ramos, GP, Nakamura, FY, Penna, EM, Wilke, CF, Pereira, LA, Loturco, I, Capelli, L, Mahseredjian, F, Silami-Garcia, E, and Coimbra, CC. Activity profiles in U17, U20, and senior women's Brazilian national soccer teams during international competitions: are there meaningful differences? J Strength Cond Res 33(12): 3414-3422, 2019-The aim of this study was to compare locomotor activity profiles of Brazilian top-class female soccer players competing at distinct age brackets (under 17 [U17], under [U20], and senior). External match load of 14 U17, 14 U20, and 17 senior female soccer players competing in 6-7 full official international matches were assessed using global positioning systems. Total distance covered, distance covered in high intensity (15.6-20 km·h), distance covered in sprints (sprint: >20 km·h), number of accelerations (Acc) >1 m·s, decelerations (Dec) >-1 m·s, and Player Load generally increased across the age brackets (U17

Asunto(s)
Esfuerzo Físico/fisiología , Carrera/fisiología , Fútbol/fisiología , Aceleración , Adolescente , Adulto , Brasil , Desaceleración , Femenino , Sistemas de Información Geográfica , Humanos , Adulto Joven
4.
J Strength Cond Res ; 33(10): 2655-2664, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29781940

RESUMEN

Coelho, DB, Pimenta, EM, Rosse, IC, Veneroso, C, Pussieldi, GDA, Becker, LK, De Oliveira, EC, Carvalho, MRS, and Silami-Garcia, E. Alpha-actinin-3 R577X polymorphism influences muscle damage and hormonal responses after a soccer game. J Strength Cond Res 33(10): 2655-2664, 2019-The purpose of this study was to evaluate indicators of muscle damage and hormonal responses after soccer matches and its relation to alpha-actinin-3 (ACTN3) gene expression (XX vs. RR/RX), considering that the R allele produces alpha-actinin-3 and provides greater muscle strength and power. Thirty players (10 XX and 20 RR/RX) younger than 16 years were evaluated in this study. Blood samples were collected immediately before, after, 2, and 4 hours after the games to assess muscle damage (creatine kinase [CK] and alpha-actin) and hormonal responses (interleukin-6 [IL-6], cortisol, and testosterone). Postgame CK was higher as compared to the pregame values in both groups and it was also higher in the RR/RX (p < 0.05) than in the XX. The concentrations of alpha-actin and IL-6 were similar for both groups and did not change over time. Testosterone was increased after the game only in the RR/RX group (p < 0.05). Cortisol concentrations in group RR/RX were higher immediately after the game than before the game, and 2 and 4 hours after the game the concentration decreased (p < 0.05). The RR and RX individuals presented higher markers of muscle microtrauma and hormonal stress, probably because they performed more speed and power actions during the game, which is a self-regulated activity. From the different responses presented by RR/RX and XX genotypes, we conclude that the genotypic profile should be taken into account when planning training workloads and recovery of athletes.


Asunto(s)
Actinina/genética , Músculo Esquelético/patología , Fútbol/fisiología , Actinina/sangre , Adolescente , Alelos , Creatina Quinasa/sangre , Expresión Génica , Genotipo , Humanos , Hidrocortisona/sangre , Interleucina-6/sangre , Polimorfismo Genético , Testosterona/sangre
5.
Games Health J ; 6(3): 159-164, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28628383

RESUMEN

PURPOSE: We aimed to analyze the acute autonomic response of obese and eutrophic prepubertal boys to an exergame (EXG) session. MATERIALS AND METHOD: Nine eutrophic (8.89 ± 2.71 years of age and 16.42% ± 6.30% body fat) and nine obese boys (8.70 ± 1.16 years of age and 40.76% ± 4.2% body fat) participated. Nutritional state was determined using World Health Organization guidelines. Variables were collected at rest, immediately post (IP), and 60 minutes after a 20 minutes EXG session. Autonomic nervous system (ANS) activity was assessed using heart rate variability in time and frequency domains, and data were analyzed using Shapiro-Wilk and ANOVA tests with Tukey post hoc. RESULTS: The obese group demonstrated an increased sympathetic activity at rest when compared with the eutrophic group (P < 0.05). The obese group also demonstrated an increased parasympathetic activity 60 minutes after the EXG session when compared with the eutrophic group (P < 0.05). CONCLUSION: We concluded that an acute session of EXG promoted ANS super compensation. We encourage research on chronic ANS response to EXG.


Asunto(s)
Fenómenos Fisiológicos Cardiovasculares , Terapia por Ejercicio/métodos , Obesidad/terapia , Obesidad Pediátrica/terapia , Juegos de Video/normas , Niño , Terapia por Ejercicio/psicología , Terapia por Ejercicio/normas , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Monitoreo Fisiológico/métodos , Obesidad/psicología , Obesidad Pediátrica/psicología , Juegos de Video/psicología
6.
Rev. bras. ciênc. mov ; 25(3): 170-181, mar.-abr.2017. ilus, tab
Artículo en Portugués | LILACS | ID: biblio-880967

RESUMEN

A evaporação de suor é o principal mecanismo de termorregulação humana durante exercícios realizados na superfície terrestre. Este importante mecanismo fisiológico de manutenção da homeostase térmica, todavia, pode levar a uma perda significativa de fluidos corporais, causando a desidratação. Evidências demonstram que a perda de líquido correspondente a 2% da massa corporal é suficiente para causar redução na capacidade de desempenho físico. Portanto, evitar a desidratação ingerindo líquidos durante o exercício é importante não só para manter a capacidade de rendimento físico, como também para prevenir contra problemas associados à hipertermia. Sendo assim, o objetivo desta revisão é discutir os efeitos da desidratação no desempenho físico de atletas e pessoas que praticam exercícios com o objetivo de obter melhoras na aptidão física. Além disso, serão apresentadas formas de se identificar e avaliar a desidratação em praticantes de exercícios, bem como aspectos relevantes para a elaboração de uma estratégia eficiente de hidratação para evitar a desidratação e também o consumo excessivo de líquidos antes, durante e após o exercício. Para a elaboração desta revisão foram realizadas buscas nas bases de dados Scielo e Pubmed Medline, utilizando-se palavras-chave como "thermoregulation", "heat stress", "exercise", "performance", "dehydration", "hydration", "fluid balance"...(AU)


Sweat evaporation is the main mechanism of human thermoregulation during exercise performed on land. This is an important physiological mechanism for maintaining the thermal homeostasis, however, it can lead to a significant body fluid loss causing dehydration. Evidences have shown that fluid losses corresponding to 2% of body weight is sufficient to cause a decrease in exercise capacity. Therefore, avoiding dehydration by drinking fluids during exercise is important not only to maintain physical performance capacity, but also to prevent problems associated with hyperthermia and dehydration. Thus, the aim of this review is to discuss the main effects of dehydration on physical performance of athletes and non-athletes who exercise in order to obtain improvements in physical fitness. In addition, we will present ways to identify and assess hydration status in exercise settings as well as relevant aspects to the development of an effective hydration strategy to prevent dehydration and also excessive fluid consumption before, during and after exercise. In this review we searched the databases Scielo and PubMed Medline using the following key-words: "thermoregulation", "heat stress", "exercise", "performance", "dehydration", "hydration", "fluid balance...(AU)


Asunto(s)
Humanos , Masculino , Femenino , Atletas , Regulación de la Temperatura Corporal , Fluidoterapia , Aptitud Física , Eficiencia
7.
J Sports Med Phys Fitness ; 57(11): 1499-1503, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28085125

RESUMEN

BACKGROUND: The aim of this study was to verify the agreement of urine, body mass variations and plasma parameters to determine the hydration status of 14 male runners (29±4 years and 54.3±5.5 mLO2/kg/min) in an official 21.1 km road race. METHODS: The mean dry-bulb temperature and air relative humidity during the road race were 25.1±2.1 °C and 54.7±2.2%, respectively. The volume of water ingested by the runners was monitored using marked volumetric plastic bottles provided at the hydration stations located at 0, 2.5, 5.0, 7.5, 10.5, 14.0, 16.0 and 18.5 km from the starting line. Hydration status was assessed using urine specific gravity (USG), urine osmolality (UOSM) and plasma osmolality (POSM). Furthermore, body mass variation (∆BM) was assessed by comparing body mass (BM) immediately prior and after the race. Total sweat was estimated by ∆BM, added water volume ingested and deducted blood volume collected. The sweat rate was calculated through total sweat and total exercise time. RESULTS: The mean water intake was 0.82±0.40 L, and the mean sweat rate and total sweating were 1440.11±182.13 mL/h and 2.67±0.23 L. After the race, the BM reduced by 1.7±0.4 kg. The ∆BM was -2.41±0.47%, and the plasma volume variation was -9.79±4.6% between pre- and post-running measurements. Despite the POSM increased post-race compared to pre-race, the UOSM and USG did not change. No significant correlations were found between POSM variation with UOSM variation (r=-0.08; P=0.71), USG variation (r=-0.11; P=0.78) or ∆BM (r=0.09; P=0.77). CONCLUSIONS: In conclusion, this study shows that both ∆BM and ∆POSM indicated a hypohydration state after exercise even though the ∆BM did not correlate significantly with ∆POSM. These results demonstrate that ∆BM is a practical method and can be sufficiently sensitive to evaluate the hydration state, but it should be utilized with caution.


Asunto(s)
Deshidratación/orina , Carrera/fisiología , Adulto , Biomarcadores/sangre , Biomarcadores/orina , Índice de Masa Corporal , Deshidratación/sangre , Ingestión de Líquidos/fisiología , Humanos , Masculino , Concentración Osmolar , Volumen Plasmático/fisiología , Sudoración/fisiología , Urinálisis
8.
Rev. bras. cineantropom. desempenho hum ; 18(6): 621-628, Nov.-Dec. 2016. tab, graf
Artículo en Inglés | LILACS-Express | ID: biblio-843416

RESUMEN

Abstract The aims of the study were: 1) to analyze the exercise intensity in several phases (six phases of 15 min) of soccer matches; 2) to compare the match time spent above anaerobic threshold (AT) between different age groups (U-17 and U-20); and 3) to compare the match time spent above AT between players’ positions (backs, midfielders, forwards and wingabcks). Forty-four male soccer players were analyzed. To express players’ effort, the heart rate (HR) was continuously monitored in 29 official matches. Further, HR corresponding to the intensity at the onset of blood lactate accumulation (OBLA) was obtained in a field test. The highest exercise intensity during match was observed in the 15-30 min period of the first half (p< 0.05). Match time spent above AT was not different between players from U-17 and U-20. In the comparison among players’ positions, wingbacks showed lower time above AT (p< 0.05) than players of other positions. The intensity of effort is higher in the 15 to 30 minutes of play (intermediate phase), probably because the players are more rested in the beginning and wearing out is progressive throughout the game. It is also noteworthy that the intensity of exercise (HR and time above AT) of wingbacks was lower, probably because they usually are required to run a larger number of sprints and need more time below the AT to recover.


Resumo Os principais objetivos do presente estudo foram: 1) comparar a intensidade de exercício em diversas fases (seis fases de 15 min) de partidas de futebol; 2) comparar o tempo de partida acima do limiar anaeróbio (LAN) entre diferentes categorias (sub-17 e sub-20); e 3) comparar o tempo de partida acima do LAN entre jogadores de diferentes posições (zagueiros, meio campistas, atacantes e laterais). Quarenta e quatro jogadores foram analisados. A intensidade de esforço como frequência cardíaca (FC) foi monitorada em 29 jogos oficiais. A FC correspondente à intensidade do OBLA (onset of blood lactate accumulation) foi obtida em um teste de campo. A maior intensidade de exercício foi observada no período 15-30 min do primeiro tempo (p< 0,05). O tempo de partida gasto acima do LAN não foi diferente entre jogadores das categorias sub-17 e sub-20. Os laterais apresentaram menor tempo acima do LAN (p< 0,05). Pode concluir-se que a intensidade do esforço foi maior em 15 a 30 min (fase intermediária), provavelmente porque os jogadores estão mais descansados no início e o desgaste é progressivo ao longo do jogo. A intensidade de exercício (FC e tempo acima LAN) dos laterais foi menor, provavelmente porque eles executam um maior número de sprints e necessitam de mais tempo abaixo do LAN para se recuperar.

9.
Appl Physiol Nutr Metab ; 41(6): 692-4, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27232187

RESUMEN

This study aimed to analyze the angiotensin-converting enzyme (ACE-I/D) allelic and genotypic frequencies in Brazilian soccer players of different ages. The study group comprised 353 players from first-division clubs in the under (U)-14, U-15, U-17, U-20, and professional categories. The allelic and genotypic frequencies did not differ significantly in any of the categories between the group of players and the control group. This was the first study of ACE-I/D polymorphism in Brazilian soccer players.


Asunto(s)
Alelos , Frecuencia de los Genes , Peptidil-Dipeptidasa A/genética , Polimorfismo Genético , Fútbol , Adolescente , Brasil , Técnicas de Genotipaje , Humanos , Masculino , Adulto Joven
10.
J Strength Cond Res ; 30(8): 2330-40, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26808850

RESUMEN

Wilke, CF, Ramos, GP, Pacheco, DAS, Santos, WHM, Diniz, MSL, Gonçalves, GGP, Marins, JCB, Wanner, SP, and Silami-Garcia, E. Metabolic demand and internal training load in technical-tactical training sessions of professional futsal players. J Strength Cond Res 30(8): 2330-2340, 2016-The aim of the study was to characterize aspects of technical-tactical training sessions of a professional futsal team. We addressed 4 specific aims: characterize the metabolic demands and intensity of these training sessions, compare the training intensity among players of different positions, compare the intensity of different futsal-specific activities (4 × 4, 6 × 4, and match simulation), and investigate the association between an objective (training impulse; TRIMP) and a subjective method (session rating of perceived exertion; sRPE) of measuring a player's internal training load. Twelve top-level futsal players performed an incremental exercise to determine their maximal oxygen consumption, maximal heart rate (HRmax), ventilatory threshold (VT), and respiratory compensation point (RCP). Each player's HR and RPE were measured and used to calculate energy expenditure, TRIMP, and sRPE during 37 training sessions over 8 weeks. The average intensity was 74 ± 4% of HRmax, which corresponded to 9.3 kcal·min. The players trained at intensities above the RCP, between the RCP and VT and below the VT for 20 ± 8%, 28 ± 6%, and 51 ± 10% of the session duration, respectively. Wingers, defenders, and pivots exercised at a similar average intensity but with different intensity distributions. No difference in intensity was found between the 3 typical activities. A strong correlation between the average daily TRIMP and sRPE was observed; however, this relationship was significant for only 4 of 12 players, indicating that sRPE is a useful tool for monitoring training loads but that it should be interpreted for each player individually rather than collectively.


Asunto(s)
Rendimiento Atlético/fisiología , Ejercicio Físico/fisiología , Esfuerzo Físico/fisiología , Fútbol/fisiología , Adolescente , Adulto , Humanos , Masculino , Consumo de Oxígeno/fisiología , Adulto Joven
11.
J Sports Med Phys Fitness ; 56(3): 241-8, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25650734

RESUMEN

BACKGROUND: The aim of this study was to investigate the association between ACTN3 genotype (RR, RX, and XX) and physical performance of 138 adult, professional, U-20 and U-17 years Brazilian first-division soccer players. METHODS: The following three parameters were investigated: first, speed, using a 30-meter sprint test with speed measured at 10 meters, 20 meters, and 30 meters; second, muscular strength, using counter-movement-jump and squat jump tests; and third, aerobic endurance using the Yo-Yo endurance test. The athletes were ranked in ascending order according to their performance in each test. After which they were divided into quartiles and clustered according to genotype and allele frequency. The χ2 was used to compare the genotype frequencies (RR, RX and RR) and allele frequencies (R and X) within and between the different quartiles of performance rating. RESULTS: No significant differences were observed in genotypic or allelic frequencies between different performance ratings. The ACTN3 genotype was not associated to any of the physical performance parameters. CONCLUSIONS: Our study provides no ervidence for an assocviation between alpha-actinin-3 R577x genotypes and differences in physical performance in adult, professional, U-20 and U-17 years Brazilian first-division soccer players.


Asunto(s)
Actinina/genética , Atletas , Rendimiento Atlético/fisiología , Polimorfismo Genético , Fútbol/fisiología , Adolescente , Brasil , Prueba de Esfuerzo , Frecuencia de los Genes , Genotipo , Humanos , Masculino , Adulto Joven
12.
Rev. bras. ciênc. mov ; 23(4): 5-11, out.-dez.2015. tab, ilus
Artículo en Inglés | LILACS | ID: biblio-846566

RESUMEN

The purpose of the present study was to assess muscle overload through changes in creatine kinase (CK) activity and serum concentration of α-actin in soccer players in response of two months of pre-season physical training. Basic procedures: Ten professional athletes (26 ± 6 years of age) undergoing arduous training were evaluated. Serum CK activity and α-actin serum concentration were determined at the beginning and end of two months of pre-season training. Effort intensity was determined throughout the training sessions by monitoring heart rate (HR). Serum CK activity was determined using the colorimetric method. Plasma α-actin concentration was evaluated using ELISA and confirmed using the Western Blot method. Main Findings: Serum CK activity and α-actin concentration were higher in the post-training period in comparison to the pre-training period (CK: PRE 65.5 ± 4.2 U/L, POST 435.7 ± 70.0 U/L, p=0.0004; α-actin by Western Blot: PRE 42.9 ± 21.6 µg/mL, POST 68.1 ± 19.1 µg/mL, p=0.0004; by ELISA: PRE 70.63 ± 10.4 µg/mL, POST 101.80 ± 17.3 µg/mL, p=0.0125). Conclusions: The significant increases in α-actin concentration and in CK activity of soccer players over the two-month pre-season indicated that an elevated training overload was imposed upon the athletes.(AU)


O objetivo do presente estudo foi avaliar a sobrecarga muscular através de mudanças na creatina quinase (CK) e concentração sérica de α-actina em jogadores de futebol de resposta de dois meses de treinamento físico de pré-temporada. Procedimentos básicos: Dez atletas profissionais (26 ± 6 anos de idade) que se submeteram aos treinamentos foram avaliados. Atividade de CK e concentração sérica de actina-α foram determinados no início e no fim de dois meses de treinamento de pré-temporada. Intensidade de esforço foi determinada ao longo das sessões de treinamento por meio do monitoramento da freqüência cardíaca (FC). Actividade de CK no soro foi determinada pelo método colorimétrico. Concentração de plasma α-actina foi avaliada utilizando ELISA e confirmado usando o método de Western Blot. Conclusões: a atividade da CK sérica e concentração α-actina foram maiores no período pós-treinamento em comparação com o período pré-treinamento (CK: PRE 65,5 ± 4,2 U/L, 435,7 ± 70,0 POST U/L, p = 0,0004; α-actina por Western Blot: PRE 42,9 ± 21,6 ng/mL, 68,1 ± 19,1 POST mcg/mL, p = 0,0004; por ELISA: PRE 70,63 ± 10,4 ng/mL, POST 101,80 ± 17,3 ng/mL, p = 0,0125). Conclusões: O aumento da atividade da CK e da concentração de actina-α após dois meses de treinamento na pré-temporada de um time de futebol indica uma sobrecarga muscular significativa imposta por este período de treinamento.(AU)


Asunto(s)
Humanos , Masculino , Adulto , Creatina , Monitores de Ejercicio , Monitoreo , Músculos
13.
Rev. bras. cineantropom. desempenho hum ; 17(4): 400-408, July-Aug. 2015. tab, graf
Artículo en Inglés | LILACS-Express | ID: lil-767170

RESUMEN

Abstract Exercise intensity monitoring has been essential for the control and planning of sports training. Thus, the aim of the present study was to assess the chronic physiological demand of soccer players during an annual soccer season using blood biomarkers. Ten professional soccer players (21.2 ± 3.7 years) participated in this study. Blood samples were collected on the day before beginning of preseason (C1); at the end of preseason and beginning of competitive calendar (C2); and at the end of the competitive calendar. Interleukin-6 (IL-6), cortisol, testosterone, testosterone/cortisol ratio, creatine kinase and alpha-actin were evaluated. Statistical analysis was performed by using ANOVA with repeated measures and the post-hoc Tukey's test. Significance level was set at P<0.05. The results showed significant differences in the following situations: testosterone - C1 higher than C2 and C3; cortisol - C3 higher than C2; testosterone/cortisol ratio - C2 higher than C1, and C3 lower than C1 and C2; creatine kinase - C2 and C3 higher than C1; alpha-actin - C3 higher than C1. IL-6 concentrations were not different between C1, C2 and C3. It could be concluded that an annual soccer season imposes high physiological demand for professional players, since relevant changes in blood biomarkers analyzed were observed.


Resumo O monitoramento da intensidade de esforço entre atletas tem se mostrado essencial para o controle e planejamento do treinamento desportivo. Assim, o objetivo do presente estudo foi avaliar por meio de biomarcadores sanguíneos a demanda fisiológica crônica de jogadores de futebol ao longo de uma temporada anual. Dez jogadores profissionais (21,2 ± 3,7 anos) participaram desse estudo. As coletas de sangue foram realizadas no dia anterior ao início da pré-temporada (C1), ao final da pré-temporada e início das competições (C2), e ao final do ano competitivo (C3). Investigou-se as variáveis cortisol, testosterona, relação testosterona/cortisol, creatina quinase, alfa-actina e interleucina 6 (IL-6). Para a análise estatística dos dados utilizou-se ANOVA para medidas repetidas e foi adotado nível de significância de 5%. Os resultados encontrados indicaram diferenças significativas nas seguintes situações: testosterona - C1 maior do que C2 e C3; cortisol - C3 maior do que C2; relação testosterona/cortisol - C2 maior do que C1, e C3 menor do que C1 e C2; creatina quinase - C2 e C3 maior do que C1; alfa-actina - C3 maior do que C1. As concentrações de IL-6 em C1, C2 e C3 não demonstraram diferenças significativas. Pode-se concluir que uma temporada anual de futebol impõe elevada demanda fisiológica entre jogadores profissionais, uma vez que foram observadas alterações relevantes sobre os biomarcadores sanguíneos analisados.

14.
Temperature (Austin) ; 2(4): 439-40, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-27227058

RESUMEN

This editorial is for the special issue "Temperature sciences in Brazil" of the journal Temperature. It focuses on the physical performance and environmental conditions during the 2014 World Cup and the coming 2016 Summer Olympics. It emphasizes that a hot and humid environment imposes a great challenge to the human thermoregulation system, can lead to performance decrements, and increases the risk of developing hyperthermia. Adequate hydration, acclimatization, and body cooling strategies are effective interventions to minimize the risks associated with exercise in the heat.

15.
PLoS One ; 9(8): e104710, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25110952

RESUMEN

This study evaluated double blind ingestions of placebo (PLA) versus 6% carbohydrate (CHO) either as capsules (c) or beverage (b) during 60 km self-paced cycling in the heat (32°C and 50% relative humidity). Ten well-trained males (mean ± SD: 26±3 years; 64.5±7.7 kg and 70.7±8.8 ml.kg-1.min-1 maximal oxygen consumption) completed four separate 60 km time trials (TT) punctuated by 1 km sprints (14, 29, 44, 59 km) whilst ingesting either PLAb or PLAc or CHOb or CHOc. The TT was not different among treatments (PLAb 130.2±11.2 min, CHOb 140.5±18.1 min, PLAc 143.1±29.2 min, CHOc 137.3±20.1 min; P>0.05). Effect size (Cohen's d) for time was only moderate when comparing CHOb - PLAb (d = 0.68) and PLAb - PLAc (d = 0.57) whereas all other ES were 'trivial' to 'small'. Mean speed throughout the trial was significantly higher for PLAb only (P<0.05). Power output was only different (P<0.05) between the sprints and low intensity efforts within and across conditions. Core and mean skin temperatures were similar among trials. We conclude that CHO ingestion is of little or no benefit as a beverage compared with placebo during 60 km TT in the heat.


Asunto(s)
Carbohidratos de la Dieta/farmacología , Ingestión de Alimentos , Ejercicio Físico/fisiología , Temperatura , Adulto , Bebidas/análisis , Método Doble Ciego , Electromiografía , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Resistencia Física/efectos de los fármacos , Esfuerzo Físico/efectos de los fármacos , Agua/metabolismo
16.
Rev. bras. cineantropom. desempenho hum ; 16(2): 129-135, 2014. tab, graf
Artículo en Inglés | LILACS-Express | ID: lil-704251

RESUMEN

Physical exercises can result in tissue damage on the muscular system, including during the preseason, which is a period of physical training aiming subsequent competitions. The aim of this study was to analyze the behavior of plasma CK as a marker of muscle damage during preseason of a professional soccer team; determine when preseason CK levels reach their peak value; and verify CK concentration on preceding moment to the first official match of the season. Professional soccer players (n = 31) attended this study (24.3 ± 3.9 years, 181.0 ± 7.0 cm, 9.1 ± 1.3%GC and 66.0 ± 4.5 mLO2/kg/min). The plasma concentration of CK was determined at the beginning of the preseason (M1), 4 (M2), 10 (M3) and 15 (M4) days after. We identified CK values of 178.2 ± 12.0, 540.0 ± 59.1, 389.8 ± 49.5, 408.7 ± 45.0 U/L for M1, M2, M3 and M4 respectively. The peak concentration of CK occurred on M2 (p<0.05). The analysis of the behavior of plasma CK revealed increased levels throughout the preseason of a professional soccer team compared to the holiday period. The peak value of CK was reached on the 4th day of preseason. The concentration of CK on the day prior to the first official match of the season proved to be in the range of values recommended for professional players.


A realização de exercícios físicos pode resultar em danos teciduais sobre o sistema muscular, inclusive durante a pré-temporada, que é um período de preparação física visando competições subsequentes. O objetivo do estudo foi analisar o comportamento da CK plasmática como marcador de dano muscular ao longo da pré-temporada de uma equipe de futebol profissional; determinar em que momento da pré-temporada os níveis de CK atingem o valor pico; e verificar a concentração de CK no dia antecedente ao primeiro jogo oficial da temporada. Participaram deste estudo 31 jogadores de futebol profissional (24.3 ± 3.9 anos, 181.0 ± 7.0 cm de altura, 9.1 ± 1.3 %GC e 66.0 ± 4.5 mlO2/kg/min). A concentração plasmática de CK foi determinada ao início da pré-temporada (M1), 4 (M2), 10 (M3) e 15 (M4) dias após. Identificaram-se valores de CK de 178.2 ± 12.0, 540.0 ± 59.1, 389.8 ± 49.5, 408.7 ± 45.0 U/L para M1, M2, M3 e M4, respectivamente. A concentração pico de CK ocorreu no M2 (p<0,05). A análise do comportamento da CK plasmática revelou níveis aumentados ao longo de toda a pré-temporada de uma equipe de futebol profissional em comparação com o período de férias. O valor pico de CK foi atingido no 4º dia da pré-temporada. A concentração de CK no dia antecedente ao primeiro jogo oficial da temporada mostrou-se na faixa de valores recomendada para jogadores profissionais.

17.
Rev. bras. cineantropom. desempenho hum ; 15(6): 667-676, Nov.-Dec. 2013. graf, tab
Artículo en Inglés | LILACS-Express | ID: lil-690200

RESUMEN

Soccer is a sport practiced worldwide, on all continents. It is considered an intermittent activity of high intensity and long duration, in which movements that require great strength and speed, such as jumps and sprints, result in high levels of muscle microtrauma, hampering athletes' training and recovery. The present study aimed to evaluate the magnitude of changes in different markers of physiological demand resulting from a soccer match in healthy individuals. Ten healthy male physical education students participated in the study and were evaluated in two matches: the semi-final and final games of the college tournament at the federal university where they studied. Blood samples were collected from each volunteer pre- and post-match. Cortisol, IL-6 and CK concentrations were increased after the match (p < 0.05). Testosterone and alpha-actin concentrations did not change. Our results indicate that changes in some of the acute response markers evaluated in players before and after competitive soccer matches provide important information for planning training or recovery, as well as nutritional strategies for improving performance.


O futebol é um esporte de abrangência mundial praticado em todos os continentes.É considerada uma atividade intermitente, de alta intensidade e longa duração, na qual as ações de grande força e velocidade como saltos e sprints implicam altos níveis de microtrauma muscular, atrapalhando o treinamento e a recuperação dos atletas. O propósito deste trabalho foi avaliar a magnitude das alterações de diferentes marcadores da demanda fisiológica em indivíduos saudáveis decorrentes de um jogo de futebol. Participaram do estudo, dez homens considerados saudáveis, estudantes de Educação Física. Os indivíduos foram avaliados em dois jogos, sendo a semifinal e a final do torneio universitário da universidade federal onde estudavam. A amostra sanguínea foi retirada de cada voluntário nos momentos pré e pós-jogo. Resultados: As concentrações de Cortisol, IL-6 e CK, apresentaram aumento pós-jogo (p<0,05). As concentrações de Testosterona e alfa-actina não se alteraram. Pode-se concluir que as alterações em parte dos marcadores das respostas agudas avaliados em jogos competitivos de futebol fornecem informações importantes para o planejamento de métodos de treinamento, recuperação ou estratégias nutricionais para o aperfeiçoamento do esporte.

18.
Rev. bras. med. esporte ; 18(5): 292-295, set.-out. 2012. tab
Artículo en Portugués | LILACS-Express | ID: lil-658107

RESUMEN

O objetivo deste estudo foi verificar o efeito da suplementação de creatina sobre o desempenho nos testes de Wingate de 10 e 30 segundos além da sua influência na concentração de lactato, ureia, creatinina e massa corporal de indivíduos fisicamente ativos. Para realização da pesquisa foram selecionados nove voluntários, sendo divididos dentro de dois grupos utilizando o procedimento duplo-cego: grupo creatina (n = 4) e grupo placebo (n = 5). A suplementação foi realizada via oral durante 10 dias, sendo que o grupo creatina ingeriu 20g de creatina (4x ao dia) nos primeiros cinco dias, seguida de uma ingesta de 5g/dia até o 10º dia. O grupo placebo recebeu a mesma dosagem, porém de maltodextrina como placebo. O protocolo de teste realizado antes e após o período de suplementação constou de um teste de Wingate adaptado de 10 segundos, seguido de um intervalo de 20 minutos para aplicação de um teste de Wingate de 30 segundos. Foram coletadas amostras de sangue antes e após o período de suplementação para análise de creatinina e ureia, lactato em repouso, 90 segundos após o teste de 10 segundos e 180 segundos após o teste de 30 segundos. A suplementação de creatina promoveu um aumento significativo (p < 0,05) na potência máxima durante o teste de 30 segundos, na potência média no teste de 10 segundos, além da concentração de creatinina. Os resultados sugerem que a suplementação de creatina pode melhorar o desempenho dos indivíduos durante exercício de alta intensidade e curta duração realizado no cicloergômetro, mas produz aumento da concentração de creatinina em repouso.


The aim of this research was to verify the effect of the creatine supplementation on performance in the 10 and 30-second Wingate tests, besides its influence in the creatinine, urea and lactate concentration and body mass of physically active men. This research selected nine volunteers, who were then separated in two groups using the double-blind procedure: creatine group (n=4) and placebo group (n=5).The supplementation was orally administered during ten days. The creatine group ingested 20g of creatine (4 times a day) in the first five days, followed by an ingestion of 5 g/day until the tenth day. The placebo group received the same dosage, but of maltodextrine instead, as placebo. The test protocol performed before and after the supplementation period consisted of an adapted 10-second Wingate test, followed by an interval of 20 minutes for application of the 30-second Wingate test .Blood samples were collected before and after the supplementation period for analysis of creatinine and urea, lactate at rest, 90 seconds after the 10-second test and 180 seconds after the 30-second test. Creatine supplementation promoted significant raise (p<0.05) in maximal power output during the 30-second test, in the mean power output in the 10 second-test, besides the creatinine concentration. The results suggest that creatine supplementation can improve individual performance in high intensity activities and short duration made in cycle ergometer; however, creatine supplementation increases the creatinine concentration at rest.

19.
Eur J Appl Physiol ; 112(4): 1495-503, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21842214

RESUMEN

Genetic factors can interfere with sporting performance. The identification of genetic predisposition of soccer players brings important information to trainers and coaches for individual training loads adjustment. Different responses to eccentric training could be observed by the genotype referred to as α-actinin-3 (ACTN3) in biomarkers of muscle damage, hormones and inflammatory responses. The aim of this study was to compare acute inflammatory responses, muscle damage and hormonal variations according to the eccentric training in soccer professional athletes with different genetic profiles of ACTN3 (XX, RX and RR). 37 soccer professional athletes (9 XX, 13 RX, 15 RR) were randomly divided into five stations associated to eccentric muscle contraction and plyometrics. Blood samples were taken from athletes pre-eccentric training, immediately after (post), 2- and 4-h post-eccentric training to determine hormone responses (cortisol and testosterone), muscle damage (CK and α-actin), and inflammatory responses (IL-6). After eccentric training, athletes XX presented higher levels for CK (4-h post), α-actin (post and 2-h post) and cortisol (post) compared to RR and RX athletes. However, RR and RX athletes presented higher levels of testosterone (post) and IL-6 (2 h post and 4 h post) compared to athletes XX. The main conclusion of this study is that professional soccer athletes homozygous to ACTN3XX gene are more susceptible to eccentric damage and present a higher catabolic state, demonstrated by metabolic, hormonal and immune responses post an eccentric training, in comparison to ACTN3RR and ACTN3RX groups.


Asunto(s)
Actinina/genética , Rendimiento Atlético , Contracción Muscular , Músculo Esquelético/metabolismo , Ejercicio Pliométrico , Polimorfismo Genético , Fútbol , Adulto , Análisis de Varianza , Biomarcadores/sangre , Brasil , Creatina Quinasa/sangre , Predisposición Genética a la Enfermedad , Homocigoto , Humanos , Hidrocortisona/sangre , Mediadores de Inflamación/sangre , Interleucina-6/sangre , Masculino , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Enfermedades Musculares/sangre , Enfermedades Musculares/genética , Enfermedades Musculares/fisiopatología , Fenotipo , Testosterona/sangre , Factores de Tiempo , Adulto Joven
20.
Rev. bras. cineantropom. desempenho hum ; 14(2): 183-191, 2012. ilus, tab
Artículo en Inglés | LILACS-Express | ID: lil-618222

RESUMEN

Most soccer matches are conducted by coaches who usually make all player substitutions allowed. Therefore, it is extremely important to study these substitutions and their effects on the intensity of effort required from players. To date, no published studies have reported on this topic using heart rate (HR) as an intensity parameter. The objective of this study was to compare effort intensity (EI) of soccer players in the following situations: 1) first half (FH-EI); 2) second half (SH-EI); 3) second half with substitutions (SHS-EI). Forty-five male soccer players (18.5±1.2 years old, 74.25±5.79 kg, 182.6±8.55 cm, 9.56±2.47 percent body fat, 56.3±4.3 mLO2/kg/min) were evaluated during 29 official games. EI was considered as the mean HR, expressed as the percentage of each player's maximal HR ( percentHRmax) and as the time spent in each intensity zone (Z) according to percentHRmax (Z1<70 percent; Z2 70-85 percent; Z3 85-90 percent; Z4 90-95 percent; Z5 95-100 percent). FH-EI (86.3±3.3 percentHRmax) was higher than SH-EI (80.6±4.4 percentHRmax) and SHS-EI (83.6±2.8 percentHRmax). SHS-EI was higher than SH-EI (p<0.05). Time spent in high-intensity zones was lower in SH-EI than in FH-EI, but higher in SHS-EI when compared to SH-EI (p<0.05). It was concluded that the decrease in EI in the second half of soccer matches was attenuated by substitutions made at halftime, as evidenced by a longer time spent in high-intensity zones when compared to SH-EI.


A maioria das partidas de futebol é conduzida por treinadores que realizam todas as substituições de jogadores permitidas. Dessa maneira, torna-se de extrema importância o estudo destas substituições e sua influência na intensidade de esforço dos atletas. Há de se mencionar, ainda, que não há nenhum estudo na literatura que tenha investigado sobre esse tópico utilizando a frequência cardíaca (FC) como um parâmetro de intensidade. O objetivo deste estudo foi comparar a intensidade de esforço (IE) dos jogadores de futebol nas situações: 1) primeiro tempo (PT-IE); 2) segundo tempo (ST-IE); 3) segundo tempo com substituições (STS-IE). Quarenta e cinco atletas de futebol do sexo masculino (18.5 ± 1.2 anos, 74.25 ± 5.79 kg, 182.6 ± 8.55 cm, 9.56 ± 2.47 por centoG, 56.3 ± 4.3 mLO2/kg/min) participaram do estudo durante 29 jogos oficiais. IE foi considerada como a média da FC, expressa em percentual da FC máxima ( por centoFCmax) de cada atleta e também de acordo com o tempo percorrido em cada zona de intensidade (Z) específica de acordo com o por centoFCmax (Z1<70 por cento; Z2 70-85 por cento; Z3 85-90 por cento; Z4 90-95 por cento; Z5 95-100 por cento). IE no PT-IE (86.3 ± 3.3 por centoFCmax) foi maior que no ST-IE (80.6 ± 4.4 por centoFC max) e que no STS-IE (83.6 ± 2.8 por centoFCmax). IE no STS-IE foi maior que no ST-IE (p<0,05). O tempo percorrido nas zonas de alta intensidade foi menor no ST-IE quando comparado com o PT-IE e maior no STS-IE quando comparado com o ST-IE (p<0,05). Conclui-se que a diminuição da IE no segundo tempo da partida de futebol foi atenuada com a realização de substituições e foi evidenciado um maior tempo de permanência em zonas de alta intensidade quando comparado com o ST-IE.

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