Intermittent Fasting Promotes Weight Loss without Decreasing Performance in Taekwondo.

Intermittent fasting (IF) is commonly used by combat sports athletes for weight loss. However, IF can decrease performance. This study aimed to investigate the effect of IF on total body mass (TBM) and Taekwondo performance. Nine athletes (seven male, two female; 18.4 ± 3.3 years) underwent 4 weeks of 12 h IF. TBM, countermovement jump (CMJ), mean kicks (MK), and total number of kicks (TNK) were compared weekly. Performance was measured in the fed state (FED) and fast state (FAST). Results showed decreased TBM in week 1 (62.20 ± 6.56 kg; p = 0.001) and week 2 (62.38 ± 6.83 kg; p = 0.022) compared to pre-intervention (63.58 ± 6.57 kg), stabilizing in week 3 (62.42 ± 6.12 kg), and no significant change in week 4 (63.36 ± 6.20 kg). CMJ performance in week 1 was lower in FED (35.26 ± 7.15 cm) than FAST (37.36 ± 6.77 cm; p = 0.003), but in week 3, FED (38.24 ± 6.45 cm) was higher than FAST (35.96 ± 5.05 cm; p = 0.047). No significant differences were found in MK and TNK in FSKTmult. RPE, KDI, and HR were similar between FED and FAST (p < 0.05). [LAC] was higher post-test compared to pre-test (p = 0.001), with higher concentrations in FED than FAST (p = 0.020). BG was higher in FED than FAST (p < 0.05) before physical tests. Therefore, IF promotes decreased TBM without decreasing performance.

Time-course of changes in performance, biomechanical, physiological and perceptual responses following resistance training sessions.

This study determined the time-course of recovery after resistance training (RT) sessions and the association between changes in performance with changes in biomechanical, physiological and perceptual parameters. After a 4-week familiarization period, 14 resistance-trained males performed 3 experimental conditions, each one including 2 sessions with a recovery interval of 24, 48 h or 72 h, in a randomized order. RT sessions consisted of 5 sets of 8-10RM on squat and leg press exercises. The resistance was equal for the 2 sessions of each condition and repetitions were performed until concentric failure. Volume load (VL) and first set volume load (FSVL) were compared between sessions. Tests before each session included countermovement jump (CMJ), maximal voluntary isometric contraction (MVIC), creatine kinase (CK) and delayed onset muscle soreness (DOMS). (2 × 3) ANOVA with effect sizes (ES) assessed the time-course of recovery and Kendall test the correlation between variables (α = 0.05). Significant interaction was observed for all variables, except for CK, where a condition main effect occurred. Comparisons between post and pre-intervals showed VL (p = 0.011;ES = -0.90) decreased for 24 h condition, while FSVL remained decreased for 48 h (p = 0.031;ES = -0.63) and DOMS increased (p = 0.001;ES = 3.52). CMJ (p = 0.025;ES = 0.25) and MVIC (p = 0.031;ES = 0.14) performance increased at 72 h. FSVL (r = 0.424), CMJ (r = 0.439), MVIC (r = 0.389) and DOMS (r = -0.327) were significantly correlated with VL (p < 0.05). Time-course of VL showed the necessity of at least 48 h for the reestablishment of performance, though better perceptual responses were evident at 72h. Thus, both recovery intervals may be beneficial after lower-limbs RT until concentric failure, though chronic effects still need to be investigated.

Efeito agudo da aplicação de vibração de corpo inteiro na força muscular de membros superiores / Acute effect of whole body vibration in the upper limbs strength

RESUMO O objetivo desse estudo foi verificar o efeito agudo da aplicação de vibração de corpo inteiro (VCI) sobre o impulso e sobre a força máxima de membros superiores. Vinte voluntários do sexo masculino, treinados, com idade: 23,8 ± 3,3 anos, foram submetidos a 3 sessões (uma sessão de familiarização e duas sessões de intervenção). Em cada uma das sessões de intervenção os voluntários realizaram uma contração voluntária máxima (CVM) de flexores do cotovelo sem aplicação de vibração e duas CVM com adição de vibração. Foram utilizadas 4 frequências de VCI (10, 20, 30 e 40Hz) distribuídas de maneira aleatória nas 4 CVM realizadas com vibração nas duas sessões de coleta. Os resultados encontrados mostraram que a força máxima e o impulso gerados na contração sem vibração foram significativamente maiores do que a força máxima e o impulso gerados durante a contração realizada com aplicação de VCI. Para o treinamento de força, a aplicação de VCI, nas frequências testadas na presente investigação, representou um menor estímulo de treinamento para os membros superiores, uma vez que gerou uma redução na força máxima e no impulso dos músculos flexores do cotovelo.

ABSTRACT The aim of this study was to investigate, from a protocol of maximal isometric contractions of the elbow flexors, the effect of WBV in the maximal force and of impulse in strength-trained individuals. Twenty male volunteers, age: 23.8 ± 3.3 years, performed 3 sessions (one familiarization session and two intervention session). The sessions were composed by 3 MVC of the elbows flexor muscles with 5 minute of rest between them. The first CVM was performed without vibration and the others, applying aleatory WBV with 10, 20, 30, 40Hz, and amplitude of 6mm. The results showed that the maximal force and of impulse obtained during the MVC without vibration was significantly higher than the maximal force and of impulse recorded during the application of WBV. For strength training, the application of WBV, in the adopted frequencies, was not able to generate sufficient stimulus to induce acute adaptations in muscle strength of upper limbs.

No acute effect of whole-body vibration on Roundhouse kick and countermovement jump performance of competitive Taekwondo athletes / Efeito agudo da vibração de corpo inteiro no desempenho do chute Roundhouse e no salto com contramovimento em atletas competitivos de Taekwondo

Abstract Little is known about the effect of whole body vibration (WBV) has on specific sports action such as taekwondo kicking technique. Fifteen individuals (10 males and 5 females; 18.6 ± 2.1 years), performed two experimental protocols on separate days: A) 1 minute exposure at 26 Hz frequency of WBV followed by countermovement jump (CMJ) test; B) 1 minute exposure at 26 Hz frequency of WBV followed by kick test. A Student's t-Test analysis was performed to evaluate the difference between performance before and after vibration intervention. The CMJ height means (cm) were 34.1 ± 6.4 before and 34.2 ± 6.5 after WBV exposure. The CMJ maximal force means were 1582.6 ± 214.3 before WBV and 1595.7 ± 205.0 after WBV, while Impulse means (N.s) were 283.3 ± 48.6 before WBV and 282.6 ± 46.6 after WBV. The kick time means (ms) were 219.9±20.31 before WBV and 218.9±19.81 after WBV. No significant differences were found regarding the application of mechanical vibration for all variables. Thus, the vibration intervention (1 minute of WBV at 26 Hz and 6 mm) adopted in this present study may have not been substantial to improve Roundhouse kick time (p=0.73), jump height (p=0.80), maximal force (p=0.78) and impulse (p=0.38) of taekwondo athletes. Future studies should investigate new vibration protocols (amplitude, frequency) and training (intensity, exercise, duration) to determine optimal parameters.

Resumo Pouco se sabe sobre o efeito da vibração de corpo inteiro (VCI) sobre o desempenho de ações esportivas específicas, como a técnica de chute do Taekwondo. Para isso, 15 atletas (10 homens e 5 mulheres; 18,6 ± 2,1 anos) realizaram dois protocolos experimentais em dias separados: A) pré-teste de salto com contramovimento (SCM), seguido de 1 minuto de exposição à frequência de 26 Hz de VCI e pós-teste de SCM; B) pré-teste de chute Roundhouse, seguido de 1 minuto de exposição à frequência de 26 Hz de VCI e pós-teste chute Roundhouse. A análise do teste t-Student foi realizada para verificar a diferença entre o desempenho pré e pós a aplicação da VCI. As médias de altura dos SCM (cm) foram 34,1 ± 6,4 pré e 34,2 ± 6,5 pós a VCI. As médias de força máxima no SCM foram 1582,6 ± 214,3 pré e 1595,7 ± 205,0 pós a VCI, enquanto as médias de Impulso (N.s) foram 283,3 ± 48,6 pré e 282,6 ± 46,6 pós a VCI. O tempo de chute (ms) foi de 219,9 ± 20,31 pré e 218,9 ± 19,81 pós a VCI. Não foram encontradas diferenças significativas em relação à aplicação de vibração mecânica para todas as variáveis. Assim, a intervenção proposta (1 minuto de VCI à 26 Hz e 6 mm) no presente estudo pode não ter sido adequada para aumentar o desempenho no teste de chute Roundhouse (p = 0,73), a altura (p = 0,80), força máxima (p = 0,78) e impulso no SCM (p = 0,38) de atletas competitivos de Taekwondo. Estudos futuros deveriam investigar novas configurações de protocolos de vibração (amplitude, frequência) e treinamento (intensidade, exercício, duração) para determinar parâmetros ótimos para melhoria do desempenho esportivo.

Efeito de 12 semanas de treinamento aeróbioem jejum sobre o emagrecimento / 12 weeks of aerobic training effect on fasting weight loss

O presente estudo objetivou verificar o efeito de 12 semanas de treinamento aeróbio em jejum sobre o emagrecimento,sendo realizado entre outubro de 2014 e março de 2015 na Faculdade Pitágoras da cidade de Betim/MG. A amostra constituiude 33 mulheres sedentárias, sem doenças metabólicas. Inicialmente as voluntárias foram submetidas à avaliações dacapacidade aeróbica (Balke-Ware) e composição corporal, sendo registrada a massa corporal total (MCT), massa muscular,massa gorda (MG) e percentual de gordura corporal (PGC), por meio de bioimpedância tetrapolar. Em seguida, as voluntáriasforam divididas randomicamente em três grupos, que realizaram treinamento aeróbio em esteira elétrica. Um dosgrupos realizou o treinamento em jejum (GJ) no período pós-absortivo, com baixa intensidade (50% da frequência cardíacade reserva), enquanto que outro grupo realizou o mesmo treinamento, mas em estado alimentado (GA). O terceiro grupopercorreu as mesmas distâncias dos outros grupos, mas com elevada intensidade (GEI) (70% da FC de reserva), no estadoalimentado. Para comparar a composição corporal e capacidade aeróbica antes e após o treinamento foi utilizado o testet pareado, enquanto que para comparar a variação percentual da MCT e do PGC dos grupos foi utilizado o teste ANOVAone-way. Os resultados apontaram que a capacidade aeróbica aumentou em todos os grupos, mas o aumento foi maior noGEI. Ainda, o GEI apresentou redução significativa no PGC e na MG, enquanto que os grupos GA e GJ não apresentaramvariações significativas na composição corporal. Não foram encontradas diferenças significativas entre os grupos em relaçãoà variação corporal da MCT e PGC. Concluiu-se que treinar em jejum não possui efeito otimizador sobre o emagrecimento.

This study aimed to verify 12 weeks of aerobic training effect on fasting weight loss performed between October 2014 andMarch 2015 at Pitágoras a city in Betim/MG. The sample was 33 sedentary women without metabolic diseases. Initially thevolunteers were submitted to aerobic capacity test (Balke-Ware) and body composition evaluation. It was recorded the totalbody mass (TBM), muscle mass (MM), fat mass (FM) and percentage of body fat (PBF) by tetrapolar bioimpedance. Then thevolunteers were randomly divided into three groups, who performed aerobic training in a treadmill. One group performedthe training in fasting (FT) in the post-absorptive period, with low intensity (50% of the heart rate reserve), while anothergroup performed the same training, but in fed state (PT). The third group ran the same distance from the other groups, butwith higher intensity (HIT) (70% of the heart rate reserve) in fed state. To compare body composition and aerobic capacitybefore and after training it was used the paired t test, while to compare the percentage change of MCT and the PGC betweengroups it was used the ANOVA one-way test. The results showed that the aerobic capacity increased in all groups, butthe increase was greater in the HIT. Further, the HIT presented a significant reduction in FM and PBF, while the FT and PTgroups showed no significant changes in body composition. No significant differences were found between the groups inrelation to variation of PGC and PBF. It was concluded that fasted aerobic training has no additional effect on weight loss.