Breakfast before resistance exercise lessens urinary markers of muscle protein breakdown in young men: A crossover trial.

OBJECTIVES: Skipping breakfast prolongs the fasting state initiated after the last meal consumed the previous day and can have negative effects on muscle protein balance. The aim of this crossover trial was to examine the effects of skipping breakfast before a single bout of resistance exercise (RE) on muscle protein breakdown (MPB), as assessed using the urinary 3-methylhistidine/creatinine ratio (3-MH/Cr). METHODS: Thirteen healthy young men, who habitually consumed breakfast (21.8 ± 1.1 y of age), were assigned to eating breakfast (EB) and skipping breakfast (SB) conditions. Participants consumed meat-free diets throughout the 5-d experiment. On day 5, individuals in the EB group consumed breakfast (497 kcal) 2.5 h before RE (75% repetition maximum), whereas those in the SB group consumed the same meal after dinner. RESULTS: In the two-way analysis of variance, significant interactions were observed with blood insulin and free fatty acid levels, and the 3-MH/Cr ratio (P < 0.05). We confirmed a significantly greater decrease in the insulin level pre-RE (P < 0.001; d = 3.281), and increases in the free fatty acid level pre-RE (P < 0.001; d = 1.437) and post-RE (P = 0.013; d = 0.811) and the 3-MH/Cr ratio 6 (P < 0.001; d = 0.878) and 8 h (P < 0.001; d = 0.634) post-RE in the SB condition than in the EB condition. CONCLUSION: Eating breakfast before RE can be beneficial for MPB suppression. The importance of breakfast consumption in terms of positive muscle protein balance is emphasized on sports fields.

Consistent Hand Dynamics Are Achieved by Controlling Variabilities Among Joint Movements During Fastball Pitching.

This study aimed to determine whether covariations among joint movements are utilized to stabilize hand orientation and movement and to determine which of the upper or lower extremities make effective use of the covariation. Joint angles during pitching were measured in 12 skilled baseball pitchers, using a motion capture system. The joint angles in 10 successful trials were used for the reconstructed motions. The reconstructed motion in the first condition was the same as for the measured motion. In the second condition, the reconstructed motion was generated with joint angles that were pseudo-randomly selected to artificially break off covariation in the measured joint-angle combination. In the third and fourth conditions, the reconstructed motions were generated with the same joint-angle combinations as the measured angles in the throwing arm and the stride leg, respectively, but pseudo-randomly selected in the other joint angles. Ten reconstructed motions were generated for each condition. Standard deviations (SDs) of hand orientation and movement direction were calculated and compared among the conditions. All SDs for the first condition were the smallest among the conditions, indicating that the movements in the measured condition used the covariation in joint angles to make the hand movement stable. The results also illustrated that some SDs in the fourth condition were smaller than those in the third condition, suggesting that the lower extremity made effective use of the covariation. These results imply that it is necessary not only to reduce variability in each joint but also to regulate joint movements to stabilize hand orientation and movement.

Relative Age Effects in Male Japanese Professional Athletes: a 25-Year Historical Analysis.

BACKGROUND: The mechanisms underlying the relative age effect (RAE), a biased distribution of birth dates, in sport events have been investigated for more than two decades. The present study comprised an historical analysis involving the most recent quarter-century (1993-2018) on RAEs among Japanese male professional athletes (soccer, baseball, basketball, and volleyball) to clarify how the RAEs changed over time. METHODS: Birth data were obtained from 7805 Japanese male professional athletes registered in 1993, 2001, 2010, and 2018. The athletes were divided into four groups based on their month of birth: quartiles Q1 (April-June), Q2 (July-September), Q3 (October-December), and Q4 (January-March of the following year). In addition, based on the data in 1993 for soccer and baseball and in 2010 for basketball and volleyball, the expected numbers of players were calculated in 2001, 2010, and 2018 for soccer and baseball, and 2018 for basketball and volleyball. RESULTS: Significant RAEs were observed among soccer and baseball players in 1993, 2001, 2010, and 2018, and strong tendencies of RAEs were found among basketball and volleyball players in 2010 and 2018. The magnitudes of the RAEs in soccer, baseball, and volleyball decreased over time, but not in basketball. CONCLUSION: The exact reasons for the decreasing or unchanging RAEs among these professional players remain unclear, but socio-cultural factors, such as low birthrates and the popularity of sports in Japan, might be related to the changing RAEs.

Characteristics of Relative Age Effects and Anthropometric Data in Japanese Recreational and Elite Male Junior Baseball Players.

BACKGROUND: The mechanisms underlying the relative age effect (RAE), a biased distribution of birth dates, in sport events have been investigated for more than two decades. The present study investigated the characteristics of the RAE in baseball and anthropometric data (height and weight) among recreational junior baseball players as well as elite players, using data extracted from national surveys. METHODS: Birth and anthropometric data were obtained from 4464 Japanese students as elementary school, junior high school, and high school players. RESULTS: Significant RAEs were noted in recreational junior high school and high school players, but not in elementary school players, and the effect size became larger with increasing grade (0.063 in elementary school players, 0.151 in junior high school players, and 0.227 in high school players). We also observed a significant RAE for elite elementary, junior high, and high school players. However, the effect size of elite players became smaller with increasing grade (0.563 in elementary school players, 0.358 in junior high school players, and 0.343 in high school players). Height and weight values were significantly larger in elite elementary and junior high school players than in recreational elementary and junior high school players, but height was almost the same between recreational and elite high school players. CONCLUSION: The characteristics of RAEs differed between recreational and elite junior baseball players. Anthropometric data were also different, depending on birth data, and between recreational and elite baseball players in elementary and junior high school students.

Effectiveness of Pilates exercise: A quality evaluation and summary of systematic reviews based on randomized controlled trials.

OBJECTIVE: The objective of this review were to summarize evidence for the effectiveness of Pilates exercise (PE) and to assess the quality of systematic review (SRs) based on randomized controlled trials (RCTs). STUDY DESIGN: A systematic review of SRs based on RCTs. METHODS: Studies were eligible if they were RCTs. Studies included those with one treatment group in which PE was applied. We searched the following databases from 1995 up to August 20, 2014: MEDLINE via PubMed, CINAHL, Web of Science, Global Health Library, and Ichushi-Web. We also searched All Cochrane Database and Campbell Systematic Reviews up to August 20, 2014. Based on the International Classification of Diseases-10 (ICD-10), we identified a disease targeted for each article. RESULTS: Nine studies met all inclusion criteria. As a whole, the quality of the articles was good. Seven studies were about "Musculoskeletal system and connective tissue (M5456)". There were two studies in "Factors influencing health status and contact with health services (Z723)". The traits of participants were for females and the comparatively young- and middle-aged. Five SRs for chronic low back pain (CLBP) concluded that there was pain-relief and functional improvement of the intervention in the short term, but two SRs were inconclusive about the effectiveness of PE. There were no adverse events described in any of the studies. CONCLUSION: Although no SR reported any adverse effect or harm by PE, there was pain-relief and functional improvement attributed to PE in the short term in participants with CLBP. There was also evidence of improved flexibility and dynamic balance, and of enhanced muscular endurance in healthy people in the short term. In addition, there may have been an effect on body composition in the short term.

Ultrasound method for estimating the cross-sectional area of the psoas major muscle.

PURPOSE: The present study aimed to develop an ultrasonographic method for estimating the cross-sectional area of the psoas major muscle. METHODS: The muscle cross-sectional area (CSA(MRI)) and thickness (MT(MRI)) of the psoas major muscle at L4-L5 on the right and left sides of the body were measured using magnetic resonance imaging in 11 healthy sedentary men age 21 to 25 yr. Ultrasonographic images were obtained at the corresponding sites where CSA(MRI) and MT(MRI) measurements were performed. From the ultrasonographic images, the thickness of the psoas major muscle (MT(US)) was analyzed on both sides of the body. RESULTS: The interclass correlation coefficient of MT(US) measurements performed on two separated days was 0.951 for the right side and 0.971 for the left side. CSA(MRI) was significantly correlated to MT(MRI) (r = 0.934 for the right side and r = 0.910 for the left side). There was no significant difference between MT(MRI) (4.68 ± 0.39 cm for the right side and 4.73 ± 0.39 cm for the left side) and MT(US) (4.67 ± 0.40 cm for the right side and 4.72 ± 0.43 cm for the left side). The MT(US) was significantly correlated to MT(MRI) (r = 0.979 for the right side and r = 0.980 for the left side) and CSA(MRI) (r = 0.947 for the right side and r = 0.916 for the left side). CONCLUSION: The current results indicate that the psoas major muscle thickness determined by the ultrasonographic method is useful for estimating the cross-sectional area of the psoas major muscle.