The expectancy-value theory: A meta-analysis of its application in physical education.

BACKGROUND: The purpose of motivating students is to enhance their learning achievement. The expectancy-value theory (EVT) has demonstrated its efficacy in motivating students in classrooms and in gymnasia. Understanding student motivation in physical education is needed. This meta-analysis review aimed to reveal the determinants and functions of EVT by evaluating the evidence in physical education research. METHODS: We followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines to identify and meta-analyze the current research literature published from January 2010 to December 2020 by generating and analyzing the effect sizes from the studies. RESULTS: A total of 31 studies were included. The results show that social support, motivation of teachers and peers, and positive class climate can predict student EVT motivation. EVT motivation predicts student learning behaviors, situational interests, fitness performance, health behavior function, out-of-school physical activity, and physical skill development. CONCLUSION: EVT motivation could facilitate learning behaviors and situational interest development in the gymnasium. It might lead to fitness enhancement, health behavior change, out-of-school physical activity participation, and physical skill development. Fostering a learning environment with a mastery-centered and/or student autonomy approach where students perceived success and the task values can enhance and maximize student EVT motivation and learning achievement.

Correction: Inhibition and interactions of alpha-amylase by daucosterol from the peel of Chinese water chestnut (Eleocharis dulcis).

Correction for 'Inhibition and interactions of alpha-amylase by daucosterol from the peel of Chinese water chestnut (Eleocharis dulcis)' by Yipeng Gu et al., Food Funct., 2021, DOI: 10.1039/D1FO00887K.

Inhibition and interactions of alpha-amylase by daucosterol from the peel of Chinese water chestnut (Eleocharis dulcis).

The alpha-amylase inhibitory effect of daucosterol purified from the peel of Chinese water chestnut (CWC), a common Chinese vegetable, was assessed. The alpha-amylase inhibitory properties were elucidated by enzyme inhibition, fluorescence quenching and molecular docking experiments. It was found that three saponins from CWC peel exhibited potent inhibitory activity on alpha-amylase and daucosterol was found to be the main inhibitory factor against alpha-amylase with a mixed-type mode. Strong fluorescence quenching of alpha-amylase was observed under static fluorescence quenching with hydrophobic interactions with daucosterol. Molecular docking revealed that the conformation of daucosterol in the high-affinity sites I and II of alpha-amylase was optimum, and hydrophobic interactions were produced by daucosterol aglycone, and hydrogen bonding by the ß-D-glucopyranosyl residue. Ingested daucosterol suppressed the elevation of blood glucose levels through inhibition of alpha-amylase in the small intestine in starch-loaded mice. This study provides data supporting the potential benefit of daucosterol from CWC peel in the treatment of diabetes.

Inhibitory properties of saponin from Eleocharis dulcis peel against α-glucosidase.

The inhibitory properties towards α-glucosidase in vitro and elevation of postprandial glycemia in mice by the saponin constituent from Eleocharis dulcis peel were evaluated for the first time. Three saponins were isolated by silica gel and HPLC, identified as stigmasterol glucoside, campesterol glucoside and daucosterol by NMR spectroscopy. Daucosterol presented the highest content and showed the strongest α-glucosidase inhibitory activity with competitive inhibition. Static fluorescence quenching of α-glucosidase was caused by the formation of the daucosterol-α-glucosidase complex, which was mainly derived from hydrogen bonds and van der Waals forces. Daucosterol formed 7 hydrogen bonds with 4 residues of the active site and produced hydrophobic interactions with 3 residues located at the exterior part of the binding pocket. The maltose-loading test results showed that daucosterol inhibited elevation of postprandial glycemia in ddY mice. This suggests that daucosterol from Eleocharis dulcis peel can potentially be used as a food supplement for anti-hyperglycemia.