Antioxidant diet supplementation enhances aerobic performance in amateur sportsmen

The effects of antioxidant diet supplements on blood lactate concentration and on the aerobic and anaerobic thresholds and their adaptations to training were analysed. Fifteen amateur male athletes were randomly assigned to either a placebo group or an antioxidant-supplemented group (90 days supplementation with 500 mg x day(-1) of vitamin E and 30 mg x day(-1) of beta-carotene, and the last 15 days also with 1 g x day(-1) of vitamin C). Before and after the antioxidant supplements, the sportsmen performed a maximal exercise test on a cycle ergometer and maximal and submaximal physiological parameters were assessed together with blood lactate concentration. Maximal oxygen uptake (VO(2max)), maximal blood lactate concentration, and the maximal workload attained rose significantly in both groups after the 3 months of training. At the end of the study, maximal blood lactate concentration was lower in the group that took supplements than in the placebo group. The percentage of VO(2max) attained at the anaerobic threshold rose significantly in both groups after 3 months of training, although the final value in the supplemented group was higher than that in the placebo group. Antioxidant diet supplements induced lower increases in blood lactate concentration after a maximal exercise test and could improve the efficiency in which aerobic energy is obtained.     

User studies in archives: the case of the Manhyia Archives of the Institute of African Studies, Kumasi, Ghana

This paper examines the use and users of the records at the Manhyia Archives of the Institute of African Studies, Kumasi. Data for the study were collected from the searcher’s ticket application forms available at the Manhyia Archives. These data collected were analysed using SPSS software. The study revealed that men and Ghanaians visit the archive most frequently. Recommendations include intensification of efforts to promote the existence, availability, and potential use of the records and the need for further research about the use of the records in the future.     

From diagrams to self-regulated learning: student teachers’ reflections on the construction of their PLE

This paper presents a study on the reflections on their PLEs by student teachers in an ICT subject of the fourth degree course in Teacher Education (Early Childhood Teacher Training) at the University of the Balearic Islands (UIB). There were four student teacher groups (n = 117) participating in this project, from the three Balearic Islands’ campuses (Mallorca, Menorca and Ibiza). The main research issues focused on in this study are: the topics highlighted from the reflections on the students’ PLEs and the reflection level achieved. To explore these issues, a content analysis technique has been used to interpret their final assignment of the students’ eportfolios, in which they had to carry out their reflections on their PLEs. For that purpose, two instruments have been designed: a system of categories and a rubric of assessment. Results show that the topics on which students reflect most are the conception of the PLE, its explicitness and its purpose. Although some improvement in students’ reflective skills was observed, conclusions lead us to the necessity of working further on the depth of reflections in order to adequately support self-regulated learning.     

Pre-exercise antioxidant enzyme activities determine the antioxidant enzyme erythrocyte response to exercise

Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H₂O₂ (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.