RESUMO
This study aimed to model adolescents' cardiorespiratory fitness performance change trajectories longitudinally across high school years and its relation to school- and individual/student-level factors. We employed hierarchical linear modeling to examine longitudinal cardiorespiratory fitness performance changes, as measured by the progressive aerobic capacity endurance run (PACER), over the years, between sexes, and in association with the school-level variables. Participants were 76,227 adolescents from 80 high schools in the mid-Atlantic region of the United States. School-level academic performance (SAP), the percent of students eligible for free and reduced-price meals (FARM), and physical education student-faculty ratio were obtained with permission from the school districts. The number of laps completed in PACER test improved throughout the first three years of high school, however, proportions of those within the healthy fitness zone (HFZ) decreased overall from 9th to 11th grade. Furthermore, the number of laps completed by adolescents appeared to have plateaued at 11th grade, with a significant decline during the final year of high school. Sex-based discrepancies in performance in meeting HFZ were evident, where girls significantly outperformed boys during 9th and 10th grades, and boys significantly outperformed girls during 12th grade. Additionally, SAP and FARM were positively and negatively, respectively, significantly associated with PACER performance at the school level. The odds ratio of adolescents performing in the HFZ declined significantly over the years, even though the number of PACER laps improved in the first three years. Concerted efforts should be targeted at improving cardiorespiratory fitness in high school due to its positive relationship to academic achievement in schools, and negative association with cardiovascular disease, metabolic syndrome, obesity, and all-cause mortality in adulthood.
RESUMO
Gracilaria eucheumoides Linn (Gracilariaceae; G. eucheumoides) is abundant in dietary fiber, which aids the clearance of excess cholesterol from the blood and maintains stable blood glucose levels. The aim of the present study was to investigate the antifatigue effect of G. eucheumoides in mice and the physiological and molecular mechanisms underlying this effect. Mice were randomly divided into four groups and three of the groups were administered different doses of G. eucheumoides extract. A loaded swimming test demonstrated that the swimming times of the low-, medium- and high-dose groups were longer than those of the control group. Examinations revealed that the liver and muscle glycogen, lactate dehydrogenase and blood glucose concentration levels of the treatment groups were higher than those of the control group (P<0.05). However, this was not the case for lactic acid concentration (P>0.05). Quantitative polymerase chain reaction showed that the gene expression levels of glucose transport protein 4 and AMP-activated protein kinase in the medium-dose group exhibited the largest increases, compared with the other treatment groups, and were 3.0- and 1.8-fold higher than those in the control group, respectively. The results of the present study indicated that G. eucheumoides exerts an antifatigue effect on mice.
RESUMO
Oligosaccharides were obtained from agar by enzymatic hydrolysis. Activated carbon adsorption separation was used to extract oligosaccharides, and gel chromatography separation was applied to further purify oligosaccharides. The result showed that activated carbon adsorption could remove the most salt impurities, and gel column chromatography could give the separation of the two kinds of oligosaccharides. ESI-MS, (13)C-NMR revealed that the molecular weight (Mw) of two oligosaccharides were 630 and 936, which were identified as neoagarotetraose and neoagarohexaose respectively.
