Using Physiological Laboratory Tests and Neuromuscular Functions to Predict Extreme Ultratriathlon Performance.

Purpose: This study aims to investigate the relationship between split disciplines and overall extreme ultra-triathlon (EUT) performance and verify the relationship among physiological and neuromuscular measurements with both fractional and total EUT performance while checking which variables could predict partial and overall EUT race time. Methods: Eleven volunteers (37 ± 6 years; 176.9 ± 6.1 cm; 77.9 ± 10.9 kg) performed two maximal graded tests (cycling and running) for physiological measurements and muscle strength/power tests to assess neuromuscular functions. Results: The correlation of swimming split times to predict overall EUT race times was lower than for cycling and running split times (r2 = 0.005; p > .05; r2 = 0.949; p < .001 and r2 = 0.925; p < .001, respectively). VO2peak obtained during running test (VO2peakrun) and VT power output assessed during cycling test (VTPO) were the highest predictors of cycling performance (r2 = 0.92; p = .017), whereas VO2peakrun and peakpower output in the cycling test (PPO) were the highest predictors of running performance (r2 = 0.94; p = .008). Conclusion: VO2peakrun and VTPO, associated to jump height assessed during countermovement jump (CMJ) test were the highest correlated variables to predict total EUT performance (r2 = 0.99; p = .007). In practical terms, coaches should include the assessment of VO2peakrun, VTPO, and CMJ to evaluate the athletes' status and monitor their performance throughout the season. Future studies should test how the improvement of these variables would affect EUT performance during official races.

Long-Term Changes in Vertical Jump, H:Q Ratio and Interlimb Asymmetries in Young Female Volleyball Athletes.

The present study aimed to examine the changes that occurred in vertical jump and isokinetic dynamometer (ISK) performances at the beginning of a preparatory period (PRE) and at the start of the competitive period (POST). Sixteen U-17 elite female volleyball players, from a national level (15.34 ± 1.19 years; 66.35 ± 7.95 kg; 169.22 ± 24.79 cm), performed bilateral squat jump (SJ), bilateral and unilateral countermovement jump (CMJ) and unilateral ISK tests for knee flexors (Fl) and extensors (Ex) both at 60°/s and at 300°/s. Peak torque (PT) and the hamstring-to-quadriceps (H:Q) ratio were assessed by concentric actions. Asymmetries were calculated by the percentage differences between dominant (DOM) and nondominant legs (NDOM). The paired Student's t-test was used for comparisons at a level of significance of 5%. The effect size was also calculated. A significant increase was found for both SJ (15%; p = 0.004; ES = 0.82) and CMJ (12%; p = 0.017; ES = 0.62). The PT of NDOM flexors at 60°/s was significantly lower than DOM both at PRE (4.6%; p = 0.048; ES = -0.22) and POST (6.3%; p = 0.037; ES = -0.33). The NDOM extensors at 60°/s had a significantly lower PT than DOM at POST (7.0%; p = 0.048; ES = -0.23). Both DOM and NDOM flexors at 60°/s had a PT enhancement at POST related to PRE (6.7%; p = 0.031; ES = 0.51 and 5.6%; p = 0.037; ES = 0.48, respectively). The PT of NDOM extensors at 300°/s increased at POST in comparison to PRE (7.9%; p = 0.038; ES = 0.27). The NDOM at 300°/s had a H:Q ratio higher than DOM both in PRE and POST (8.6%; p = 0.041; ES = 0.37 and 11.6%; p = 0.013; ES = 0.71, respectively), and the highest H:Q ratios were lower than the reference values (<80%). The asymmetry of the unilateral CMJ was higher at POST than at PRE (102%; p = 0.03; ES = 0.81). The PT for the flexors at 300°/s and the H:Q ratio at POST exceeded 10%. In conclusion, a training program of 15 weeks increased the neuromuscular performance of young volleyball athletes, but many H:Q ratios and asymmetries remained out of the normal recommendation. Volleyball professionals should carefully apply an adequate training program to enhance physical fitness performance without increasing the risk of lower limb injuries concurrently.

Metabolic and immune/inflammatory alterations induced by a triathlon under extreme conditions.

Purpose: To investigate the effects of triathlon racing under extreme conditions on metabolic and immune/inflammatory responses. Methods: Thirteen amateur athletes participated in an extreme triathlon competition (swim - 3.8 km; cycling - 180 km; running - 4 2 km; with a 3,700 m accumulated altitude). Blood samples were collected on three different occasions: pre-competition (baseline), immediately post-competition (IM), and 12 h post-competition (12 h) to evaluate glycemic and lipid profiles, leukocytes count, and cytokines levels in plasma and in whole-blood cell culture supernatant stimulated or not with LPS. Results: Decreased glucose and triglycerides levels, increased LDL, and a significant leukocytosis were observed at IM and 12 h compared to baseline. In addition, higher serum levels of IL-6, IL-8, and IL-10 were found at IM than in baseline and post-12 h. Whereas increased IL-12p40 levels were observed for 12 h compared to baseline. At baseline, in LPS-stimulated cell culture, IL-6, IL-8, and IL-12p70 were higher, while IL-12p40 levels were lower than non-stimulated cell culture. At IM, IL-12p40 levels were unchanged, while higher levels of other cytokines were found in LPS-stimulated cell culture compared to non-stimulated cell culture. The 12 h results showed higher levels of IL-6, IL-8, and IL-10 in LPS-stimulated cell culture than in non-stimulated cell culture. Additionally, a significant negative correlation between circulating glucose levels and IL-6 was found. Conclusion: The triathlon competition's performance under extreme conditions has remarkable impacts on the lipid profile and systemic immune/inflammatory responses. For the first time, significant alterations in the cytokine responses of whole blood cell culture to LPS-stimulation in baseline, IM, and 12h were demonstrated.

Short-Term Cardiac Autonomic Recovery after a Repeated Sprint Test in Young Soccer Players.

The aim of this study was to describe the time course (within 2 h post-exercise) of heart rate variability (HRV) recovery following a traditional repeated sprint ability (RSA) test applied to youth soccer players. Twenty-four young soccer players (18.4 ± 0.5 years) undertook the following assessments: (1) 10 min rest in the seated position for HRV assessment; (2) a repeated sprint ability (RSA) test; (3) passive recovery in the seated position for 10 min, immediately after finishing the RSA test and 1 h and 2 h post-RSA test. During the HRV measurements (using the natural log of root mean square difference of successive normal RR intervals-lnRMSSD) the participants were instructed to assume a comfortable sitting position, remaining awake and breathing spontaneously for 10 min. Magnitude-based inference was used in the analyses. After the RSA test, the post-1 h measure was almost certainly lower than the resting measure, but almost certainly higher than the lnRMSSD measured post-RSA test. The lnRMSSD post-2 h was likely lower than the resting lnRMSSD and very likely higher than post-1 h. In conclusion, lnRMSSD is severely depressed after performing an RSA test, and reactivation is incomplete after 2 h of passive recovery. This result should be considered by practitioners when applying successive training sessions within intervals shorter than 2 h.

Functional Screening Tests: Interrelationships and Ability to Predict Vertical Jump Performance.

There are several methods used in sports science to identify asymmetries in athletes, given their purported relevance to injury prevention and performance optimization. We aimed to verify whether asymmetries provided by isokinetic assessments, jump tests, and tensiomyography (TMG) are associated with each other, and whether their respective functional indices are related to jumping ability. TMG parameters, unilateral and bilateral squat-jump (SJ) and countermovement-jump (CMJ) performances, and peak torque in knee-extension and flexion with angular velocities of 60o/s and 300o/s for twenty-four soccer players were retained for analyses. Asymmetry was detected by examining the percentage difference between dominant and non-dominant legs. The median-split technique was used to identify the best and worst performers in SJ and CMJ tests. Results revealed that the asymmetries detected in the three different methods were not interrelated. Curiously, better performances in SJ and CMJ tests were associated with higher asymmetry levels. Furthermore, only the knee-extension peak torque at both angular velocities was correlated moderately to largely (r=0.48-0.66) with jump performance. Despite their recognized ability to predict the risk of injury, the absence of interrelationships between TMG, isokinetic tests, and unilateral jumps precludes their single use as a unique functional screening diagnostic. Finally, and very importantly, lower-limb asymmetry is not necessarily related to impaired vertical jump performance in soccer players.

Competitive balance in football: a comparative study between brazil and the main european leagues (2003-2016) / Equilíbrio competitivo no futebol: um estudo comparativo entre brasil e as principais ligas europeias (2003-2016)

ABSTRACT The present study compared the competitive balance (CB) of Brazilian professional football with those of Germany, Spain, France, England, Italy and Portugal first division leagues, between the period from 2003/2004 to 2016/2017. In addition, a trend line of the period and the overall effect was analysed. The CB was measured by the concentration of points by the first four teams placed in the final standings (C4ICB). Descriptive values ​​showed that the competitions were not fully balanced (i.e. C4ICB> 100). (Md= 145, 148, 148, 152 and 155, respectively, p<0.05), with no differences for France (Md= 140), compared to Germany, Spain, Italy, England and Portugal (Md= 140, p> 0.05). The CB trend lines for Spain, Portugal and the overall effect were significant and showed a decline in the period (p <0.05). There was more stable behavior for Brazil and Italy, observing tendencies to significant models for the increments in the German and French leagues and a reduction in the CB in the English league. It is concluded that the Brazilian league was the most balanced in this period. Globally, there has been a growing inequality in these leagues, which may implicate in the success and attractiveness of the leagues in the future.

RESUMO O presente estudo comparou o equilíbrio competitivo (EC) do futebol brasileiro com os da Alemanha, Espanha, França, Inglaterra, Itália e Portugal), na primeira divisão, entre o período de 2003/2004 a 2016/2017. Além disso, verificou-se a linha de tendência do período e o efeito global. O EC foi medido através da concentração de pontos pelos quatro primeiros colocados na tabela final de classificação (C4 Index of Competitive Balance; C4ICB). Valores descritivos mostraram competições não totalmente equilibradas (i.e., C4ICB>100). C4ICB do campeonato brasileiro (Md=133) foi menor em comparação aos da Alemanha, Espanha, Itália, Inglaterra e Portugal (Md=145, 148, 148, 152 e 155, respectivamente; p<0.05), sem diferenças para a França (Md=140; p>0.05). As linhas de tendência de EC's de Espanha, Portugal e de efeito global foram significativas e demonstraram declínio no período (p<0.05). Para Brasil e Itália houve comportamento com perfil mais estável, observando tendências a modelos significativos para os incrementos nos campeonatos da Alemanha e França e redução de EC no campeonato da Inglaterra. Conclui-se que o campeonato brasileiro foi o torneio menos desequilibrado neste período. De forma global, houve uma crescente desigualdade de equilibrio nessas competições no período analisado o que pode comprometer o sucesso e atratividade no futuro.

Erratum: Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice.

[This corrects the article on p. 257 in vol. 13, PMID: 28702435.].

Interval and continuous aerobic exercise training similarly increase cardiac function and autonomic modulation in infarcted mice.

The present study aimed to compare the effects of moderate-intensity continuous and high-intensity interval exercise training (ET) on exercise tolerance, cardiac morphometry and function, hemodynamic, and cardiac autonomic modulation in myocardial infarcted mice. Wild-type mice (WT) were divided into four groups: sedentary WT (S); WT myocardium infarction sedentary (IS); WT myocardium infarction underwent to moderate-intensity continuous ET (MICT), and WT myocardium infarction underwent to high-intensity interval ET (MIIT). After 60 days of descending coronary artery ligation, moderate-intensity continuous ET consisted of running at 60% of maximum, while the high-intensity interval training consisted of eight sprints of 4 min at 80% of maximum and a 4-min recovery at 40% of maximum. Both exercises were performed 1 hr a day, 5 days a week, during 8 weeks. Results demonstrated that IS showed elevated exercise tolerance, as well as decreased hemodynamic and heart function, and autonomic control. On the other hand, both programs of ET were equally effective to increase all parameters, without further differences between the groups. In conclusion, the results of the present study showed that myocardial infarction leads to damage in both investigated strains and the two types of physical exercise attenuated the major impairments provoked by myocardial infarction in exercise tolerance, cardiac structure, cardiac function, hemodynamic and cardiac autonomic modulation.

Análise da produção científica sobre atletismo no Brasil: uma revisão sistemática / Scientific production of track and field in Brazil: a systematic review

O objetivo deste estudo foi analisar a produção científica brasileira sobre o Atletismo entre 1999 e 2013. Foram identificados 162 artigos, e selecionados 55 estudos que abordaram o Atletismo como temática principal do estudo. Destes, 43 artigos (78,2%) foram relacionados com a Biodinâmica do Movimento Humano e 12 (21,8%) com a Pedagogia do Movimento. Analisando os estudos selecionados (caraterização a posteriori das análises), 30,9% (17) correspondiam à pesquisas na área de fisiologia do exercício, 20% (11) a lesões no esporte, 10% (6) sobre biomecânica, 7,3% (4) a psicologia do esporte e 7,3% (4) a nutrição esportiva. As áreas com menos pesquisas foram o treinamento esportivo, a iniciação esportiva e a história/sociologia do esporte com 5,5% (3) cada uma. A pedagogia do esporte e do dopping, ficaram com a menor proporção de estudos, sendo 3,6% (2) cada uma. Seis estudos não apresentavam uma única modalidade como foco central na investigação, outros 15 enfocaram corridas de fundo e meio undo, 8 em corridas de rua e maratonas, 7 em corridas de velocidade, 6 em atletismo paralímpico e, com menor percentual, as provas de salto horizontal, arremessos e lançamentos e o atletismo escolar que tiveram 1 estudo cada. Conclui-se que é importante considerar os critérios de avaliação dos cursos de PósGraduação adotados pela CAPES, pois no modo atual o sistema parece limitar a investigação na área da Pedagogia do Movimento. Necessita-se também qualificar a pesquisa sobre o Atletismo no Brasil e desenvolver pesquisas com melhor aporte metodológico (estudos longitudinais, de intervenção, de validação de métodos, de revisão de literatura e qualitativos) bem como melhorar a amostragem e diversificar as investigações em diferentes provas do Atletismo...(AU)

The aim of this study was to analyze the Brazilian scientific production on Athletics between 1999 and 2013. A total of 162 articles were identified, and 55 studies were selected that approached Athletics as the main theme of the article. Of these, 43 articles (78.2%) were related to Biodynamics of the Human Movement, and 12 (21.8%) with Pedagogy of the Human Movement. Analyzing the studies, 30.9% (17) corresponded to research in the physiology of the exercise, 20% (11) corresponded to studies on sports injuries, 10% (6) on sports biomechanics, 7.3% ( 4) sports psychology and 7.3% (4) sports nutrition. The areas with the least research were sports training, sports initiation and sport history / sociology, with 5.5% (3) in each one, and the lowest proportion of studies occurred in the area of sports pedagogy and doping, with 3.6% (2) of the studies found in the literature review. Six studies did not present a single modality as a central focus in the investigation, another fifteen focused in middle and long-distance events, eight road running and marathon, seven sprints, six studies focused on Brazilian Paralympic athletes, and with a lower percentage jumping and throwing events and school athletics with one study each. It is concluded that it is important to consider the evaluation criteria of the courses and thus, the entry of teachers into the country's postgraduate programs, as this seems to limit research in the area of Pedagogy of Human Movement. It is also necessary to qualify the research on Athletics in Brazil, to develop researches with better methodological aproach, that is, longitudinal studies, intervention studies, validation studies of methods, studies of literature review and qualitative studies, to improve the sample in the studies and diversify the research evidence...(AU)

Bar velocities capable of optimising the muscle power in strength-power exercises.

This study aimed at testing whether there are mean propulsive velocities (MPVs) capable of maximising the mean propulsive power (MPP) during the execution of bench press (BP), bench throw (BT), half squat (HS) and jump squat (JS). Additionally, we assessed the differences in MPP/MPV between ballistic and traditional exercises. Seventeen male rugby sevens players performed MPP tests in BP, BT, HS and JS and maximum isometric force (MIF) tests in HS and BP. The JS presented higher MPP (977.4 ± 156.2 W) than the HS (897.9 ± 157.7 W) (P < 0.05); the BP (743.4 ± 100.1 W) presented higher MPP than the BT (697.8 ± 70.4 W) (P < 0.05). Ballistic exercises presented higher optimum MPV (JS = 1.02 ± 0.07 m·s-1; BT = 1.67 ± 0.15 m·s-1) than traditional exercises (HS = 0.93 ± 0.08 m·s-1; BP = 1.40 ± 0.13 m·s-1) (P < 0.05). The optimum MPP in the JS, BT, HS and BP occurred at 28.2 ± 5.79, 23.3 ± 4.24, 32.4 ± 9.46 and 27.7 ± 5.33% of the MIF, respectively. The coefficient of variation (CV) of MPV at optimum MPP ranged from 7.4% to 9.7%, while the CV of %MIF ranged from 18.2% to 29.2%. The MPV is a more precise indicator of the optimum loads than the percentages of MIF due to its low inter-subject variability as expressed by CV. Therefore, MPV can be used to determine the optimum power load in the four investigated exercises.

Second-leg home advantage in the Copa Libertadores da América (2005-2015)

Aims: To investigate the home advantage (HA) in the Copa Libertadores da América (CLA) from 2005 to 2015. Methods: A naive analysis was applied considering how many times a team that played the second leg at home qualified for the next round. To verify differences between home, away and draw results, the Chi-square ( χ2 ) and the Full Bayesian Significance Test were applied. For the binomial variables ("Home" or "Away"), the probability of second-leg knockout occurrence was calculated. Results: The probability of second-leg HA varied from 27.27% to 63.64% suggesting fluctuations of second-leg HA during competitive phases (round of 16, quarterfinals, semi-finals and final matches) and decision forms (full time, goals away rule or penalty-shoots). Conclusion: The results counteract the common belief that there is a large advantage to playing the second match of a two-leg tie at home during all competition phases. Penalty-shots seemed to affect positively the second-leg HA. Despite the causes of second leg HA in CLA need to be better investigated, soccer coaches could to use these results to think better strategies to win your knockout matches.(AU)

Correction: Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation.

[This corrects the article DOI: 10.1371/journal.pone.0142078.].

Previous participation in FIFA World-Cup: the key to success?

This qualitative-descriptive investigation examining the influence exerted by experienced soccer-players on the ranking obtained from the four best-ranked by their teams in the last four FIFA World Cups (WC). They were divided into experienced-players (at least one WC participation [+1WC]) or non-experienced players (no previous participation [1WC]). Thereafter, they were classified according to their contribution in each of the playoff matches in a given WC: STARTER (started all matches); START/SUBST (started at least one match); SUBST/BENCH (did not start any matches, but replaced a player in at least one match); and BENCH (did not participate in matches). The sample was composed of 33.7% experienced and 66.3% non-experienced players. The number of players +1WC in finalist teams was significantly higher than in the non-finalist teams (p<0.05). In addition, when compared with the non-finalist teams, the finalists presented significantly higher number of players STARTER with +1WC (p<0.05). Possibly, the selection of experienced players to participate in WC may be an effective strategy to achieve better competitive performance

Post-analysis methods for lactate threshold depend on training intensity and aerobic capacity in runners. An experimental laboratory study / Métodos de pós-análise do limiar do lactato dependem da intensidade de treinamento e da capacidade aeróbica dos corredores. Um estudo laboratorial experimental

ABSTRACT CONTEXT AND OBJECTIVE: This study aimed to evaluate different mathematical post-analysis methods of determining lactate threshold in highly and lowly trained endurance runners. DESIGN AND SETTING: Experimental laboratory study, in a tertiary-level public university hospital. METHOD: Twenty-seven male endurance runners were divided into two training load groups: lowly trained (frequency < 4 times per week, < 6 consecutive months, training velocity ≥ 5.0 min/km) and highly trained (frequency ≥ 4 times per week, ≥ 6 consecutive months, training velocity < 5.0 min/km). The subjects performed an incremental treadmill protocol, with 1 km/h increases at each subsequent 4-minute stage. ­Fingerprint ­blood-lactate analysis was performed at the end of each stage. The lactate threshold (i.e. the running velocity at which blood lactate levels began to exponentially increase) was measured using three different methods: increase in blood lactate of 1 mmol/l at stages (DT1), absolute 4 mmol/l blood lactate concentration (4 mmol), and the semi-log method (semi-log). ANOVA was used to compare different lactate threshold methods and training groups. RESULTS: Highly trained athletes showed significantly greater lactate thresholds than lowly trained runners, regardless of the calculation method used. When all the subject data were combined, DT1 and semi-log were not different, while 4 mmol was significantly lower than the other two methods. These same trends were observed when comparing lactate threshold methods in the lowly trained group. However, 4 mmol was only significantly lower than DT1 in the highly trained group. CONCLUSION: The 4 mmol protocol did not show lactate threshold measurements comparable with DT1 and semi-log protocols among lowly trained athletes.

RESUMO CONTEXTO E OBJETIVO: O objetivo do presente estudo é avaliar modelos matemáticos de pós-análise do limiar de lactato em grupos de corredores de longa distância muito ou pouco treinados. TIPO DE ESTUDO E LOCAL: Estudo laboratorial experimental. Hospital Público Universitário Terciário. MÉTODO: Vinte e sete corredores homens foram divididos em: pouco treinados (frequência < 4 vezes por semana, < 6 meses, velocidade ≥ 5,0 minutos/km) e muito treinados (frequência ≥ 4 vezes por semana, ≥ 6 meses, velocidade < 5,0 minutos/km). Os participantes foram submetidos a protocolo de esteira escalonado (1% inclinação) = 1 km/h por fase (4 minutos). Ao fim de cada estágio, análise da "impressão digital" metabolômica foi realizada. O limiar do lactato (i.e. velocidade em que o lactato sanguíneo aumenta exponencialmente) foi medido utilizando-se três métodos: aumento de 1 mmol/l da concentração, concentração absoluta de 4 mmol e método semi-log. ANOVA foi utilizada para comparar os diferentes limiares de lactato e grupos. RESULTADO: Atletas muito treinados apresentaram limiares de lactato maiores que os corredores pouco treinados, independentemente do método de cálculo utilizado. Comparando todos os corredores juntos, as análises de aumento de 1 mmol/l e semi-log não foram diferentes, enquanto a concentração absoluta de 4 mmol/l foi significativamente mais baixa que as dos dois outros métodos. Essas mesmas tendências foram observadas ao se compararem os métodos de limiar de lactato no grupo menos treinado. Entretanto, a análise absoluta de 4 mmol/l foi menor do que a do aumento de 1 mmol/l no grupo muito treinado. CONCLUSÃO: O método concentração absoluta de 4 mmol não mostrou mensurações comparáveis de limiar do lactato quando comparado com os protocolos aumento de 1 mmol/l e semi-log nos atletas pouco treinados.

Post-analysis methods for lactate threshold depend on training intensity and aerobic capacity in runners. An experimental laboratory study.

CONTEXT AND OBJECTIVE: This study aimed to evaluate different mathematical post-analysis methods of determining lactate threshold in highly and lowly trained endurance runners. DESIGN AND SETTING: Experimental laboratory study, in a tertiary-level public university hospital. METHOD: Twenty-seven male endurance runners were divided into two training load groups: lowly trained (frequency < 4 times per week, < 6 consecutive months, training velocity ≥ 5.0 min/km) and highly trained (frequency ≥ 4 times per week, ≥ 6 consecutive months, training velocity < 5.0 min/km). The subjects performed an incremental treadmill protocol, with 1 km/h increases at each subsequent 4-minute stage. -Fingerprint -blood-lactate analysis was performed at the end of each stage. The lactate threshold (i.e. the running velocity at which blood lactate levels began to exponentially increase) was measured using three different methods: increase in blood lactate of 1 mmol/l at stages (DT1), absolute 4 mmol/l blood lactate concentration (4 mmol), and the semi-log method (semi-log). ANOVA was used to compare different lactate threshold methods and training groups. RESULTS: Highly trained athletes showed significantly greater lactate thresholds than lowly trained runners, regardless of the calculation method used. When all the subject data were combined, DT1 and semi-log were not different, while 4 mmol was significantly lower than the other two methods. These same trends were observed when comparing lactate threshold methods in the lowly trained group. However, 4 mmol was only significantly lower than DT1 in the highly trained group. CONCLUSION: The 4 mmol protocol did not show lactate threshold measurements comparable with DT1 and semi-log protocols among lowly trained athletes.

Caffeine Ingestion Increases Estimated Glycolytic Metabolism during Taekwondo Combat Simulation but Does Not Improve Performance or Parasympathetic Reactivation.

OBJECTIVES: The aim of this study was to evaluate the effect of caffeine ingestion on performance and estimated energy system contribution during simulated taekwondo combat and on post-exercise parasympathetic reactivation. METHODS: Ten taekwondo athletes completed two experimental sessions separated by at least 48 hours. Athletes consumed a capsule containing either caffeine (5 mg∙kg-1) or placebo (cellulose) one hour before the combat simulation (3 rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration and rating of perceived exertion were measured before and after each round, while heart rate (HR) and the estimated contribution of the oxidative (WAER), ATP-PCr (WPCR), and glycolytic (W[La-]) systems were calculated during the combat simulation. Furthermore, parasympathetic reactivation after the combat simulation was evaluated through 1) taking absolute difference between the final HR observed at the end of third round and the HR recorded 60-s after (HRR60s), 2) taking the time constant of HR decay obtained by fitting the 6-min post-exercise HRR into a first-order exponential decay curve (HRRτ), or by 3) analyzing the first 30-s via logarithmic regression analysis (T30). RESULTS: Caffeine ingestion increased estimated glycolytic energy contribution in relation to placebo (12.5 ± 1.7 kJ and 8.9 ± 1.2 kJ, P = 0.04). However, caffeine did not improve performance as measured by attack number (CAF: 26. 7 ± 1.9; PLA: 27.3 ± 2.1, P = 0.48) or attack time (CAF: 33.8 ± 1.9 s; PLA: 36.6 ± 4.5 s, P = 0.58). Similarly, RPE (CAF: 11.7 ± 0.4 a.u.; PLA: 11.5 ± 0.3 a.u., P = 0.62), HR (CAF: 170 ± 3.5 bpm; PLA: 174.2 bpm, P = 0.12), oxidative (CAF: 109.3 ± 4.5 kJ; PLA: 107.9 kJ, P = 0.61) and ATP-PCr energy contributions (CAF: 45.3 ± 3.4 kJ; PLA: 46.8 ± 3.6 kJ, P = 0.72) during the combat simulation were unaffected. Furthermore, T30 (CAF: 869.1 ± 323.2 s; PLA: 735.5 ± 232.2 s, P = 0.58), HRR60s (CAF: 34 ± 8 bpm; PLA: 38 ± 9 bpm, P = 0.44), HRRτ (CAF: 182.9 ± 40.5 s, PLA: 160.3 ± 62.2 s, P = 0.23) and HRRamp (CAF: 70.2 ± 17.4 bpm; PLA: 79.2 ± 17.4 bpm, P = 0.16) were not affected by caffeine ingestion. CONCLUSIONS: Caffeine ingestion increased the estimated glycolytic contribution during taekwondo combat simulation, but this did not result in any changes in performance, perceived exertion or parasympathetic reactivation.

Transference effect of vertical and horizontal plyometrics on sprint performance of high-level U-20 soccer players.

The aim of this study was to investigate the effects of adding vertical/horizontal plyometrics to the soccer training routine on jumping and sprinting performance in U-20 soccer players. The vertical jumping group (VJG) performed countermovement jumps (CMJ), while the horizontal jumping group (HJG) executed horizontal jumps (HJ). Training interventions comprised 11 sessions, with volume varying between 32 and 60 jumps per session. The analysis of covariance revealed that CMJ height and peak force improved only in the VJG, and that HJ distance and peak force improved in both groups. Velocity in 20 m (VEL 20 m) did not improve in either group; however, velocity in 10 m (VEL 10 m) presented a moderate positive effect size (ES = 0.66) in the HJG, while the ES was large (1.63) for improvement in the 10-20 m acceleration in the VJG, and it was largely negative (-1.09) in the HJG. The transference effect coefficients (calculated by the equation: TEC = result gain (ES) in untrained exercise/result gain (ES) in trained exercise) between CMJ and VEL 20 m and ACC 10-20 m were 1.31 and 2.75, respectively. The TEC between HJ and VEL 10 m, VEL 20 m and ACC 0-10 m were 0.44, 0.17 and 0.44, respectively. The results presented herein indicate that the plyometric training-axis is decisive in determining neuromechanical training responses in high-level soccer players.

Tensiomyography parameters and jumping and sprinting performance in Brazilian elite soccer players.

Tensiomyography has been suggested as an indirect marker of muscle stiffness, which is associated with strength/power performance. Therefore, it is reasonable to suggest that tensiomyography parameters could be associated with power-related motor tasks. The purpose of this study was to investigate the association between tensiomyography parameters (from rectus and biceps femoris) and jumping and sprinting abilities in elite soccer players. In addition, we used tensiomyography parameters to compare the lateral symmetry between dominant and non-dominant legs. Twenty elite soccer players (age: 23.3 ± 4.8 years; height: 183.5 ± 6.6 cm; weight: 77.8 ± 7.5 kg) volunteered to participate in the study. Significant moderate negative correlations between biceps femoris displacement and contact time (r = -0.5, p = 0.03), rectus femoris displacement and contact time (r = -0.51, p = 0.02), and a significant moderate correlation between biceps femoris displacement and reactive strength index (r = 0.5, p = 0.03) were found. There were no correlations between tensiomyography parameters and power-related motor tasks. In addition, no differences in tensiomyography parameters between dominant and non-dominant legs were found. Our data suggest that tensiomyography parameters are not associated with power-related motor tasks performance in elite soccer players.

Half-squat or jump squat training under optimum power load conditions to counteract power and speed decrements in Brazilian elite soccer players during the preseason.

The purpose of this study was to test which specific type of exercise (i.e., jump squat (JS) or half-squat (HS)) is more effective at maintaining speed and power abilities throughout a preseason in soccer players. Twenty-three male soccer players were randomly allocated into two groups: JS and HS. The mean propulsive power, vertical jumping ability, and sprinting performance were evaluated before and after 4 weeks of a preseason period. The optimum power loads for the JS and HS exercises were assessed and were used as load-references. The soccer players performed 10 power oriented training sessions in total. Both JS and HS maintained power in JS and speed abilities (P > 0.05, for main effects and interaction effect) as indicated by ANCOVA. Both groups demonstrated reduced power during HS (ES = -0.76 vs. -0.78, for JS and HS, respectively); both groups improved acceleration (ACC) from 5 to 10 m (ES = 0.52). JS was more effective at reducing the ACC decrements over 0-5 m (ES = -0.38 vs. -0.58, for JS and HS, respectively). The HS group increased squat jump height (ES = 0.76 vs. 0.11, for HS and JS, respectively). In summary, JS is more effective in reducing the ACC capacity over very short sprints while HS is more effective in improving squat jump performance. Both strategies improve ACC over longer distances. New training strategies should be implemented/developed to avoid concurrent training effects between power and endurance adaptations during professional soccer preseasons.

Efeito do treinamento resistido em paciente com fibromialgia: estudo de caso / Effect of resistance training in patients with fibromyalgia: a case report

A fibromialgia (FM) é uma doença idiopática de ordem reumatológica e incurável que causa dores crônicas e possui tratamento complexo e multifatorial. O exercício físico pode fazer parte do tratamento por atenuar parte dos sintomas da FM, porém a literatura ainda carece de informações sobre tipo, intensidade, duração e frequência ótimos contra os sintomas da FM. O objetivo do presente estudo foi verificar o efeito de 12 semanas de treinamento resistido em uma paciente com FM que não fazia tratamento farmacológico. Os resultados indicaram que 12 semanas de treinamento resistido foi capaz de reduzir as dores, melhorar a capacidade funcional, o bem-estar geral e a qualidade de vida da paciente. O treinamento resistido pareceu atenuar os efeitos negativos da FM e parece ser uma ferramenta promissora para pacientes com FM que gostem desse tipo de atividade.

Fibromyalgia (FM) is an idiopathic rheumatological order and incurable desease that causes chronic pain and has complex and multifactorial treatment. Exercise may be a part of treatment by relieving some of the symptoms of FM, but the literature still lacks optimal information about type, intensity, duration and frequency against the symptoms of FM. The aim of this study was to verify the effect of 12 weeks of resistance training in a patient with FM that had no pharmacological treatment. The results indicated that 12 weeks of resistance training was able to reduce pain, improve functional capacity, general well-being and quality of life of the patient. Resistance training appeared to attenuate the negative effects of FM and seems to be a promising tool for patients with FM who enjoy this kind of activity.