The Relationship between Maximum Oxygen Consumption （VO2 Max） and Body Fat Percentage of the Male Secondary School Pupils （15-18 Years）

The purpose of this study was to find out the type of relationship between VO2 max and percentage of body fat in male secondary school students. The research sample consisted of 30 male students studying at Al-Khawarizmi High School in Tlemcen. Their average age was 16.56 ± 0.69. We based our research on books and scientific journals, site visits, and personal meeting. We used the descriptive approach. The test was carried out and the measurements were taken at the institution＇s yard and the doctor＇s office respectively. We used the running test for one mile to measure the maximum oxygen consumption. The skin folds were taken in three areas： the chest, abdomen and mid-thigh, to estimate the proportion of fat in the body. The results showed that the relationship between maximum oxygen consumption and body fat percentage was strongly reversed at a significant level of 0.01, with Pearson correlation coefficient -0.597.

Physical Performance of Migrant Schoolchildren with Marginal and Severe Iron Deficiency in the Suburbs of Beijing

Objectives To investigate relationship between iron deficiency of different degrees and physical performance and habitual activity of migrant schoolchildren at the age of 11-14 years. Methods Ninety one randomly selected schoolchildren were divided into three groups according to their iron status. Iron status including hemoglobin （Hb）, serum ferritin （SF）, serum iron （SI） and sTfR was determined. Physical performance tests included maximum oxygen consumption （VO2max） and maximum work time. Energy expenditure （EE） and daily physical activity were estimated by recording 24-h heart rate （HR）. Dietary intake was assessed with frequency questionnaires, and physical activity level was estimated with frequency and physical activity questionnaires. Results Severe iron deficiency （IDA） impaired the aerobic capacity and habitual physical activity. When fat-free mass （FFM） was considered, VO2max （VO2max/FFM） was significantly lower in the iron-marginal group than in the iron-adequate groups among girls （P=0.02）, but such a deference was not found among boys （P=0.28）. Aerobic activity and EE at leisure were significantly lower in the severe iron deficient group than in the marginal iron deficient and iron adequate groups. Net HR at leisure time was correlated with lib, log SF, body weight, and FFM （P〈0.05）. Conclusion The functional effect of iron deficiency on physical performance and habitual physical activity rely on the degree of current iron deficiency. Severe iron deficiency significantly impairs both aerobic capacity and habitual physical activity. Iron-marginal deficiency impairs VO2max/FFM in girls, rather than in boys.

The effect of flutamide on the physical working capacity and activity of some of the key enzymes for the energy supply in adult rats

The aim of the study was to assess the effects of androgen receptor antagonists on the physical working capacity and activity of some of the key muscle enzymes for the energy supply in rats. Young adult male Wistar rats were divided into two groups. One group received 15 mg kg-1 of flutamide daily for 6 days a week and the other group served as control for 8 weeks. At the beginning and at the end of the experiment, all rats were subjected to submaximal running endurance （SRE）, maximum time to exhaustion （MTE）, and maximal sprinting speed （MSS） tests. At the end of the trial, maximum oxygen consumption （VO2max） test was performed and the levels of testosterone, erythrocytes, hemoglobin as well as enzyme activity of succinate dehydrogenase （SDH）, lactate dehydrogenase （LDH）, and NAD.H2-cytochrome-c reductase （NAD.H2） of the gastrocnemius muscle were measured. Serum testosterone of the flutamide-treated rats was higher than that of the controls, which verifies the effectiveness of the dose chosen. MTE and SRE of the anti-androgen-treated group were lower compared with the initial values. Flutamide treatment decreased the activity of SDH and NAD.H2 compared with the controls. We found no effect of the anti-androgen treatment on MSS, VO2max, running economy, LDH activity, and hematological variables. Our findings indicate that the maintenance of the submaximal and maximal running endurance as well as the activity of some of the key enzymes associated with muscle oxidative capacity is connected with androgen effects mediated by androgen receptors.