Beta-hydroxy-beta-methylbutyrate supplementation preserves fat-free mass in collegiate boxers during acute body mass loss.

Acute body mass loss before competitions in combat sports usually leads to loss in fat-free mass. Beta-hydroxy-beta-methylbutyrate (HMB) has been shown to increase skeletal muscle mass and muscle strength in various muscle wasting conditions. This study investigated the effect of HMB supplementation on body composition and sport-specific performance in well-trained boxers consuming a hypocaloric diet. Twelve male college boxers were divided into the HMB and placebo (PLA) groups using a body weight-matched single-blind parallel design. The study comprised a 6-day weight loss period (days 1-6), followed by a 3-day competition period (days 7-9). The participants in both the groups consumed 16 kcal/kg/day, including 1.6-1.7 g/kg of carbohydrates, 1.2-1.3 g/kg of protein, and 0.45-0.5 g/kg of fat during the 9-day period. The HMB group consumed 3 g/day HMB. Body composition measurement, isometric mid-thigh pull (IMTP), and a simulated boxing match were performed at baseline and on days 7, 8, and 9. Fasting blood samples were collected on the day before day 1 and on days 7, 8, and 9. Body mass was significantly decreased after the 6-day weight loss period (HMB group: baseline: 69.4 ± 11.2 kg, day 7: 67.1 ± 11.2 kg; PLA group: baseline: 68.6 ± 12.1 kg, day 7: 65.7 ± 11.5 kg, P < 0.05) while it was unchanged on the 3-day competition period in both the groups. Fat-free mass in the HMB group was maintained throughout the 9-day period (baseline: 56.7 ± 9.3 kg, day 7: 56.3 ± 8.7 kg, day 9: 55.8 ± 9.5 kg) whereas it significantly decreased on days 7 and 9 compared to the baseline in the PLA group (baseline: 55.2 ± 6.4 kg, day 7: 54.1 ± 6.6 kg, day 9: 54.0 ± 6.6 kg, P < 0.05). In the PLA group, the average and maximal heart rates in round 1 and the average heart rate in round 2 on days 8 and 9 were significantly lower than those at baseline, while these parameters were unchanged in the HMB group. The maximal force and the rate of force development in the IMTP remained unchanged among the different timepoints in both the groups. The blood biochemical parameters were similar at any timepoint between the PLA and HMB groups. HMB supplementation during acute weight loss may preserve fat-free mass and maintain heart rate response in subsequent simulated matches in well-trained boxers. In addition, HMB supplementation had a nonsignificant effect on glucose, fat, and protein metabolism during energy restriction.

Results from the Chinese Taipei (Taiwan) 2022 report card on physical activity for children and youth.

Background: /Objective: In Taiwan, physical inactivity is highly prevalent among children and adolescents. Chinese Taipei (Taiwan) joined the Global Matrix 3.0 in 2018 to share local data on childhood physical activity and related factors with the international community. This study reports the grades for 10 indicators endorsed by the Global Matrix 4.0 and 1 additional indicator. Methods: Local data for school-aged children and adolescents (approximately 5-17 years old) from 2017 to 2022 were used to determine the grades. The data were obtained from online academic databases and websites of government agencies. The highest priority was given to national surveys, followed by studies using nationally representative samples. Results: The data revealed very poor Overall Physical Activity, Organized Sport Participation, and Active Play (F, D-, and F, respectively). Active Transportation, Sedentary Behavior, and Family and Peers were also below average (C-, D+, and D-, respectively). Taiwan's central and local governments have recognized the importance of physical activity by implementing related policy and improving public sports facilities. Accordingly, School and Community and the Built Environment both received a grade of A-, and Government Strategies and Investments received a B+. Physical Fitness received an INC for lack of data. An additional indicator, body mass index, received a grade of B-. Conclusions: Despite great effort by governments and schools, physical activity levels are low and sedentary behavior is prevalent among Taiwanese children and adolescents.

Report card grades on physical activity for children and adolescents from 18 Asian countries: Patterns, trends, gaps, and future recommendations.

Background: Physical inactivity is a persistent and worsening population health concern in Asia. Led by the Active Healthy Kids Global Alliance, Global Matrix (GM) initiative provides an opportunity to explore how regional and cultural differences across 18 Asian countries relate to physical activity (PA) participation among children and adolescents. Objectives: To synthesize evidence from the GM2.0 to GM4.0 (2016-2022) in Asian countries. Methods: Report Card grades on behavioral/individual and sources of influence indicators were reported from 18 Asian countries. Letter grades were converted into numerical values for quantitative analyses. Based on this, cross-sectional and longitudinal analyses were conducted to investigate patterns and trends. Qualitative evidence synthesis was performed based on Report Card grades and published papers to identify gaps and suggest future recommendations. Results: In total, 18 countries provided grades for at least one round of GM, 12 countries provided grades for at least two rounds, and seven countries provided grades for all three GMs. Of possible grades, 72.8%, 69.2%, and 76.9% of the grades were assigned from GM 2.0 to GM 4.0, respectively. In terms of the Report Card grades, there was a slight decrease in behavioral/individual indicators from "D+" in GM 2.0 to "D-" in GM 3.0 but this reverted to "D" in GM 4.0. For the sources of influence, a "C" grade was given in all three rounds of GM. Longitudinal observation of seven Asian countries that provided grades in all three rounds of GM revealed that grades are generally stable for all indicators with some country-specific fluctuations. In future GM initiatives and research, considerations should be made to provide more accurate and rich data and to better understand contextual challenges in evaluating certain indicators such as Active Transportation, Active Play, and Physical Fitness in particular. Further, macro level factors such as socioeconomic/cultural disparities and gender-specific barriers, ideology, or climate change should also be proactively considered in future research as these factors are becoming increasingly relevant to indicators of GM and United Nation's Sustainable Development Goals. Conclusions: Participation from Asian countries in GM has increased over the years, which demonstrates the region's enthusiasm, capacity, and support for global PA promotion efforts. The efforts to promote a physically active lifestyle among children and adolescents should be a collective interest and priority of the Asia region based on the gaps identified in this paper.

Intermittent Cooling Reduces Perceived Exertion but Has No Effect on Baseball Hitting or Defense Performance in a Hot Environment.

Hot environments can impair the complex cognitive functions that are crucial to baseball hitting and defense. This study investigated the effects of intermittent forehead and neck cooling on the hitting and reactive agility of baseball players in hot environments. Ten male collegiate baseball players played 7-inning intrasquad games in a hot environment (31.1°C - 33.4°C), completing one cooling and one control trial in a randomized crossover design. In the cooling trial, the participants placed ice-cold towels on their forehead and neck for 3 min during offensive half innings. Hitting and reactive agility tests, a go/no-go task, and the Stroop Color and Word Test were administered before and after each game. The games in the hot environment significantly increased rectal temperatures to the same level in the control (38.15°C ± 0.31°C, p < 0.001) and cooling (38.08°C ± 0.24°C, p < 0.001) trials. Intermittent cooling significantly reduced forehead and tympanic temperatures, perceived exertion, and thermal sensation during the game. Swing power significantly increased after the game, but the exit velocity of batted balls did not significantly differ in both trials. Reactive agility was significantly impaired after the game in the control trial (before: 0.367 ± 0.109 s, after: 0.491 ± 0.212 s, p = 0.008) but displayed a trend of decrease in the cooling trial (before: 0.390 ± 0.183 s, after: 0.518 ± 0.282 s, p = 0.066). The game and cooling intervention had no significant effects on the reaction time or error rate in the go/no-go task and Stroop Color and Word Test. The results showed that intermittent cooling during a baseball game in a hot environment reduces perceived exertion and thermal sensation but has no significant effect on hitting, defense performance, or cognitive function.

Thirty minutes of moderate-intensity downhill or level running has no effect on postprandial lipemia: A randomized controlled trial.

Elevated postprandial triglyceride (TG) concentrations are linked to a relatively high risk of cardiovascular disease. Eccentric endurance exercise, such as downhill walking and running, can provide metabolic benefits similar to concentric exercise. However, whether eccentric exercise affects postprandial lipemia remains unknown. Nine healthy young men performed level running (trial) or downhill running (DR trial, -15% slope) at 60% [INSIDE:1]O2max or rest (CON trial) for 30 min in a randomized crossover design. The participants were fed a high-fat meal the next day. Blood and expired gas samples were collected before and 0.5, 1, 2, 3, 4, 5, and 6 h after the meal. Muscle soreness was measured using a visual analog scale. The DR trial induced mild muscle damage. During the 6-h postprandial period, serum TG concentrations and area under the curve (AUC) were similar across the three trials. The DR trial had a significantly higher AUC of nonesterified fatty acid concentrations and a significantly lower AUC of glucose concentrations than the CON trial. The results suggested that neither moderate-intensity DR nor running a level surface had a significant effect on lipemia after a high-fat meal. However, DR improved the postprandial glycemic response.

Influence of Hot Environment on Pitching and Hitting Performance in Professional Baseball.

ABSTRACT: Huang, J-H, Chiu, Y-C, and Chang, C-K. The influence of hot environment on pitching and hitting performance in professional baseball. J Strength Cond Res 35(11): 3251-3255, 2021-Baseball is usually played outdoors during the warmest months of the year. The long exposure to a hot environment may lead to hyperthermia and subsequent impaired cognitive function, which is crucial for hitting and pitching performance in baseball. The purpose of this study was to investigate the effect of apparent temperature on pitching and hitting performance in Chinese Professional Baseball League games in Taiwan. Each pitched and batted ball from a total of 480 regular season games in 2018 and 2019 was analyzed. Each game was categorized into one of the 4 groups on the basis of the average apparent temperature at which it was played: cold (below 21° C), warm (21-28° C), hot (28-34° C), or extremely hot (above 34° C). Differences in pitching and hitting variables were compared across the 4 groups. In the extremely hot environment, slugging percentage, isolated power, base on balls per 9 innings, home runs per 9 innings, and walks plus hits per inning were all significantly higher than those in the other 3 environments. The results suggest that offensive production was significantly increased in extremely hot environments in the Chinese Professional Baseball League. It is recommended that pitchers could adopt cooling interventions to alleviate the decline in performance in an extremely hot environment.

Results from the Chinese Taipei (Taiwan) 2018 Report Card on physical activity for children and youth.

BACKGROUND/OBJECTIVE: Taiwan is facing a high prevalence of physical inactivity in children and adolescents, which has led to rising obesity and morbidity levels in young people. Chinese Taipei (Taiwan) joined the Global Matrix 3.0 to share the local information on childhood physical activity and related factors with the international community. This study reports the grades for 10 indicators endorsed by the Global Matrix 3.0. METHODS: The local data for school-aged children and youth (∼5-17 year-olds) from 2010 to 2018 were used to determine the grades. The highest priority was given to the national survey data released by the government or academic institutions, followed by academic publications using nationally representative samples. Government or academic publications relying on only regional samples were excluded. RESULTS: The data showed very poor Overall Physical Activity and Organized Sport Participation (F and D-, respectively). The grades for Active Transportation and Sedentary Behavior were C-. Low physical activity levels and high screen time may have led to sub-optimal Physical Fitness levels (B-). The central and local governments have recognized the importance of physical activity by creating related policy and improving facilities. Therefore, School, Community and the Built Environment, and Government Strategies and Investments all received the grade of B+. Active Play and Family and Peers received INC for a lack of sufficient data. CONCLUSIONS: Despite great effort by the governments and schools, physical activity and fitness levels are low while sedentary behavior is prevalent in Taiwanese children and youth.

Applying a Treatment Effects Model to Investigate Public Amenity Effect on Physical Activity of the Elderly.

The increasing elderly population puts significant health, economic, and social burdens on society. Physical activity is one of the most cost-effective ways to maintain the health of the elderly. This study adopts a treatment effects model to investigate the causal relationship between environment attributes and physical activity among the elderly, while taking endogeneity into account. The data were collected from 274 participants by face-to-face interviews in Taichung, Taiwan. Performing physical activity regularly in parks is the most important measure of the amount of physical activity by the elderly. Providing sufficient and accessible parks in metropolitan residential neighborhoods could be one of the most cost-effective ways to promote physical activity for the elderly living in midsize Asian cities.

Scratch wound closure of myoblasts and myotubes is reduced by inflammatory mediators.

Complex interactions exist between muscle repair processes and acute inflammatory responses that are initiated by exercise-induced muscle damage. The purpose of this study was to examine whether inflammatory mediators secreted by activated macrophages affect the migration of myogenic cells to the injury site. Migration was measured using a scratch wound closure assay in C2 C12 -derived myogenic cells incubated in activated macrophage-conditioned medium. Both myoblast and myotube migrations were significantly reduced in activated macrophage-conditioned medium compared with control medium. Furthermore, we demonstrated that the inhibitory effect on myoblast and myotube migrations was mediated, at least in part, by the two major cytokines secreted by activated macrophages, tumour necrosis factor (TNF)-α and interleukin (IL)-6. These findings suggest that the migration rate of myogenic cells may be reduced by inflammatory mediators. It may provide useful insights for future researches on the role of macrophages in the process of muscle repair and regeneration.

The Supplementation of Branched-Chain Amino Acids, Arginine, and Citrulline Improves Endurance Exercise Performance in Two Consecutive Days.

The central nervous system plays a crucial role in fatigue during endurance exercise. Branched-chain amino acids (BCAA) could reduce cerebral serotonin synthesis by competing with its precursor tryptophan for crossing the blood brain barrier. Arginine and citrulline could prevent excess hyperammonemia accompanied by BCAA supplementation. This study investigated the combination of BCAA, arginine, and citrulline on endurance performance in two consecutive days. Seven male and three female endurance runners ingested 0.17 g·kg-1 BCAA, 0.05 g·kg-1 arginine and 0.05 g·kg-1 citrulline (AA trial) or placebo (PL trial) in a randomized cross-over design. Each trial contained a 5000 m time trial on the first day, and a 10000 m time trial on the second day. The AA trial had significantly better performance in 5000 m (AA: 1065.7 ± 33.9 s; PL: 1100.5 ± 40.4 s) and 10000 m (AA: 2292.0 ± 211.3 s; PL: 2375.6 ± 244.2 s). The two trials reported similar ratings of perceived exertion. After exercise, the AA trial had significantly lower tryptophan/BCAA ratio, similar NH3, and significantly higher urea concentrations. In conclusion, the supplementation could enhance time-trial performance in two consecutive days in endurance runners, possibly through the inhibition of cerebral serotonin synthesis by BCAA and the prevention of excess hyperammonemia by increased urea genesis.

Pacing Strategies in Elite Individual-Medley Swimmers: A Decision-Tree Approach.

PURPOSE: This study aimed to examine pacing strategies and identify the stroke that has the most significant impact on overall performance in men's and women's 200-m and 400-m individual-medley events from 2000 to 2021. METHODS: The time in each lap and overall race was retrieved from the World Aquatics website. The standardized time for each stroke in individual medley was calculated by dividing the actual time by a reference time specific to each stroke. The reference time was derived from the respective laps in single-stroke finals in the 2017 World Swimming Championships. The decision-tree method was used for analysis. The dependent variables were qualified or nonqualified in heats and semifinals, and winning medals in finals. The independent variables were the ratio of standardized time in each stroke to the sum of standardized time in all 4 strokes. RESULTS: Swimmers who spent a higher ratio of standardized time in the butterfly stroke (>0.236-0.245) are associated with a higher likelihood of winning medals or qualifying for the next stage in most men's and women's 200-m and 400-m individual medley. Butterfly exhibited the highest normalized importance that distinguished medalists from nonmedalists in the finals. The front-crawl stroke is the second most important determinant in medalists in men's and women's 200-m individual medley, whereas backstroke and breaststroke were the second most important in men's and women's 400-m individual medley, respectively. CONCLUSION: Individual-medley swimmers who were excellent in butterfly and conserved energy in butterfly had a higher likelihood of success.

Low- or moderate-carbohydrate calorie-restricted diets have similar effects on body composition and taekwondo performance after high-carbohydrate recovery meals.

Low-carbohydrate (LC) diets are popular among general and athletic populations attempting to lose body mass. This study investigated the effect of a 7-day LC or moderate-carbohydrate (MC) calorie-restricted diet followed by 18-h recovery on body composition and taekwondo-specific performance. In this randomised cross-over study, 12 male taekwondo athletes consumed an LC (10% of carbohydrate, 41% of protein, 49% of fat, and 15.8 ± 0.4 kcal/kg/day) or an isocaloric MC diet (60% of carbohydrate, 30% of protein, and 10% of fat) for 7 days. The participants then consumed a carbohydrate-rich recovery dinner (39.2 ± 3.1 kcal/kg) followed by breakfast (6.2 ± 0.4 kcal/kg) in both the trials. Three repeated sprint ability (RSA) tests were conducted after breakfast. The taekwondo-specific reaction battery was administered before the first RSA test and after each RSA test. The participants experienced similar magnitudes of significant loss of body mass in the LC (-2.4 ± 1.7%) and MC (-2.3 ± 1.7%) trials. Fat mass and fat percentage significantly decreased in the MC trial but remained unchanged in the LC trial after body mass loss. Fat free mass was maintained in both the trials. The average and peak power in the RSA tests and the premotor reaction time were similar between the trials. The participants experienced significantly higher fatigue in the LC trial. In conclusion, both the diets can help athletes rapidly lose body mass while maintaining performance as long as an adequate amount of carbohydrate is consumed during the recovery period.

Resting salivary levels of IgA and cortisol are significantly affected during intensive resistance training periods in elite male weightlifters.

The aim of this study was to investigate the cumulative effects of intensive resistance training on salivary immunoglobulin A (SIgA) and cortisol responses in elite male weightlifters. Eleven elite male Taiwanese weightlifters were trained through 3 training stages before a national weightlifting competition, and this was followed by a 2-week recovery stage. Resting saliva samples were collected once in each of the 4 stages. Salivary concentrations of total protein (TP), SIgA, lactoferrin, and cortisol were measured. The results showed that (a) salivary TP concentrations were not significantly affected; (b) resting levels of SIgA, the ratio of SIgA to TP (SIgA/TP), cortisol, and the ratio of cortisol to TP (cortisol/TP) were significantly higher in the training stages than in the recovery stage; (c) a positive correlation was revealed between the ratios of SIgA/TP and cortisol/TP; and (d) the resting salivary lactoferrin concentrations and the ratio of lactoferrin to TP (lactoferrin/TP) were significantly lower in stage 1 than in the recovery stage. The findings in this study suggest that prolonged, intensive resistance training exerts cumulative effects on SIgA and cortisol responses in elite weightlifters.

Global Matrix 4.0 Physical Activity Report Card Grades for Children and Adolescents: Results and Analyses From 57 Countries.

BACKGROUND: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions. METHODS: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country. RESULTS: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally. CONCLUSIONS: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

Relationships among salivary immunoglobulin A, lactoferrin and cortisol in basketball players during a basketball season.

The aim of this study was to examine the changes and relationships of immune and stress parameters of basketball players during a basketball season. Eight members of National Taichung University basketball team volunteered to participate. Saliva samples were collected at rest and before the start of practice or competition at seven time points during the intense training, competition and recovery period. Salivary immunoglobulin A (sIgA), cortisol, and lactoferrin were measured during training and competition period and compared with those measured at the fourth recovery week. Relationships among immune and stress parameters were evaluated. Compared with those detected at the fourth recovery week, significant decreases in secretion rates and absolute concentrations of sIgA and lactoferrin were observed at times of intense training and competition. In addition, significant increases in secretion rates and absolute concentrations of salivary cortisol were observed during intense training and competition period and the first week of recovery. Moreover, a significant inverse correlation (r = -0.28; P < 0.05) that existed between secretion rates of sIgA and cortisol as well as a positive correlation (r = 0.32; P < 0.05) that existed between secretion rates of sIgA and lactoferrin was measured. Our results demonstrated that the secreted cortisol was induced and the mucosal immunity of the participants was suppressed during the basketball season. The inverse correlation existed between secretion rates of sIgA and cortisol may indicate a possible role of cortisol in the strenuous exercise-induced immunosuppression. Our results also suggest that a delicate balance may exist between mucosal innate and adaptive immune responses.

The interactive effect of exercise and immunosuppressant cyclosporin A on immune function in mice.

Cyclosporin A (CsA) is an effective immunosuppressive agent and exerts its actions by interfering with the activation of T cells. There is growing evidence that regular exercise improves immune function. However, the effects of exercise on immune functions in patients taking CsA are unclear. Here, we examine the interactive effects of CsA administration and regular exercise on immune function in mice. Forty-eight BALB/c mice were randomly assigned to one of six groups with eight mice per group: 0-Ex (no CsA/no exercise), 0 + Ex (no CsA + exercise), 10-Ex (10 mg kg(-1) day(-1) CsA/no exercise), 10 + Ex (10 mg kg(-1) day(-1) CsA + exercise), 20-Ex (20 mg kg(-1) day(-1) CsA/no exercise), and 20 + Ex (20 mg kg(-1) day(-1) CsA + exercise). The three exercise groups were trained for 8 weeks, three times a week, at approximately 75% maximum oxygen uptake (VO(2max)). Nitric oxide and interferon-gamma secretions by mitogen-activated macrophages and spleen cells, respectively, were higher in exercise groups than in non-exercise groups receiving the same doses of CsA. The results of this study indicate that regular exercise may enhance Type I helper T cell functions in mice receiving 10 or 20 mg kg(-1) day(-1) CsA. Our results demonstrate that moderate regular exercise modulates the immune function of CsA-treated mice. However, whether this exercise-induced immunomodulatory effect is beneficial or detrimental to CsA-treated patients needs to be clarified.

Private doctors' practices, knowledge, and attitude to reporting of communicable diseases: a national survey in Taiwan.

BACKGROUND: Epidemiological surveillance of infectious diseases through the mandatory-reporting system is crucial in the planning and evaluation of disease control and prevention program. This study investigated the reporting behavior, knowledge, and attitude to reporting communicable disease in private doctors in Taiwan. The differences between the reporting and non-reporting doctors were also explored. METHODS: A total of 1250 clinics were randomly sampled nationwide by a 2-stage process. Data were collected from 1093 private doctors (87.4% response rate) using a self-administered structured questionnaire. Four hundred and six (37.2%) doctors reported having diagnosed reportable communicable diseases. Among them, 340 (83.5%) have the experiences of reporting. RESULTS: The most common reasons for not reporting were "do not want to violate the patient's privacy", "reporting procedure is troublesome", and "not sure whether the diagnosed disease is reportable". Significantly higher proportions of the non-reporting doctors considered the reporting system inconvenient or were not familiar with the system. The highest percentage (65.2%) of the non-reporting doctors considered that a simplified reporting procedure, among all measures, would increase their willingness to report. In addition, a significantly higher proportion of the non-reporting doctors would increase their willingness to report if there has been a good reward for reporting or a penalty for not reporting. CONCLUSION: The most effective way to improve reporting rate may be to modify doctor's attitude to disease reporting. The development of a convenient and widely-accepted reporting system and the establishment of a reward/penalty system may be essential in improving disease reporting compliance in private doctors.

SNP combinations in chromosome-wide genes are associated with bone mineral density in Taiwanese women.

Osteoporosis is a major public health problem, mainly quantified by low BMD. Eleven polymorphisms were investigated in this study; TNFalpha-857 (rs1799724), TGFbeta1-509 (rs1800469), osteocalcin (rs1800247), TNFalpha-308 (rs1800629), PTH BstB I (rs6254), PTH Dra II (rs6256), IL-1ra (VNTR), HSP70 hom (rs2227956), HSP 70-2 (rs1061581), CTR (rs1801197), and BMP-4 (rs17563). The relationship between the combined polymorphisms in different genomic regions and BMD variation was investigated. Among the female subjects, the proportion of subjects with low BMD in low BMI group (< or = 18.50) was significantly higher than that of the middle (18.51-22.99) and high (> or = 23.00) BMI groups (P < 0.05). In post-menopausal women, there was a significant association between low BMD and genotypes ranging from 2 to approximately 7 SNPs. For two combined SNPs, the portion of subjects with low BMD was significantly higher in those with CC-AA genotypes in rs1799724-rs1800629, compared to those with non-CC-AA genotypes in post-menopausal women and the combination of all women. Similarly, part of the combined SNPs with rs1799724-rs1800629-rs6254-rs6256-IL-1ra-rs2227956-rs1801197 was significantly associated with reduced BMD. After controlling for age and BMI, post-menopausal women with certain specific SNP combination had a 3.54- to 4.68-fold increased risk for low BMD, comparing to other SNP combinations. In conclusion, our data suggest that several gene polymorphisms may be cooperatively involved in the development of osteoporosis.

The Effect of Branched-Chain Amino Acids, Citrulline, and Arginine on High-Intensity Interval Performance in Young Swimmers.

High-intensity interval training has drawn significant interest for its ability to elicit similar training responses with less training volume compared to traditional moderate-intensity protocols. The purpose of this study was to examine the effect of co-ingestion of branched-chain amino acids (BCAA), arginine, and citrulline on 8 × 50 m high-intensity interval swim performance in trained young swimmers. This study used a randomized cross-over design. Eight male (age 15.6 ± 1.3 years) and eight female (age 15.6 ± 0.9 years) swimmers completed both amino acids (AA) and placebo (PL) trials. The participants ingested 0.085 g/kg body weight BCAA, 0.05 g/kg body weight arginine and 0.05 g/kg body weight citrulline before the swim test in the AA trial. The average 50 m time was significantly shorter in the AA trial than that in the PL trial. The AA trial was faster than the PL trial in the first, second, and the seventh laps. The AA trial showed significantly higher plasma BCAA concentrations and lower tryptophan/BCAA ratio. The other biochemical parameters and ratings of perceived exertion were similar between the two trials. The results showed that BCAA, arginine, and citrulline, allowed the participants to swim faster in a high-intensity interval protocol in young swimmers.

Report Card Grades on the Physical Activity of Children and Youth Comparing 30 Very High Human Development Index Countries.

BACKGROUND: To better understand the childhood physical inactivity crisis, Report Cards on physical activity of children and youth were prepared concurrently in 30 very high Human Development Index countries. The aim of this article was to present, describe, and compare the findings from these Report Cards. METHODS: The Report Cards were developed using a harmonized process for data gathering, assessing, and assigning grades to 10 common physical activity indicators. Descriptive statistics were calculated after converting letter grades to interval variables, and correlational analyses between the 10 common indicators were performed using Spearman's rank correlation coefficients. RESULTS: A matrix of 300 grades was obtained with substantial variations within and between countries. Low grades were observed for behavioral indicators, and higher grades were observed for sources of influence indicators, indicating a disconnect between supports and desired behaviors. CONCLUSION: This analysis summarizes the level and context of the physical activity of children and youth among very high Human Development Index countries, and provides additional evidence that the situation regarding physical activity in children and youth is very concerning. Unless a major shift to a more active lifestyle happens soon, a high rate of noncommunicable diseases can be anticipated when this generation of children reaches adulthood.