Effects of an eight-week exercise program on parameters of the lipid profile of female students.

BACKGROUND: Increased lipid levels are one of the major risk factors for the development of cardiovascular diseases. The aim of the current study was to evaluate the effect of short-term (8 weeks) aerobic exercise of moderate to vigorous intensity on lipid profile in young healthy females. METHODS: 27 female students (mean age 20.5 ± 1 year) completed 8 weeks of aerobic training that included two exercise sessions of continuous aerobic activity of moderate intensity (running 35-60 min) and one exercise session with interval training of vigorous intensity. Intervention aerobic capacity and lipid profile were examined before and after the exercise. RESULTS: Exercise intervention has caused a decrease of low density lipoprotein levels per 9.8% (from 2.52 ± 0.47 to 2.27 ± 0.53 mmol/L; p < 0.001) and significant improvement of high density lipoprotein (HDL) levels per 22.7% (from 1.29 ± 0.24 to 1.59 ± 0.24 mmol/L; p < 0.001), total cholesterol/HDL ratio per 17.2 % and aerobic capacity (VO2max) per 3.8 % (43.9 ± 3.7 to 45.56 ± 3.63 mLO2/kg/min). CONCLUSIONS: The results support the hypothesis that a short-term aerobic exercise intervention of moderate to vigorous intensity may have significant effects on blood lipid profile in young healthy females.

A Comparison of Dietary Habits between Recreational Runners and a Randomly Selected Adult Population in Slovenia.

INTRODUCTION: The aim of the study was to compare the dietary habits of recreational runners with those of a random sample of the general population. We also wanted to determine the influence of gender, age and sports performance of recreational runners on their basic diet and compliance with recommendations in sports nutrition. METHODS: The study population consisted of 1,212 adult Slovenian recreational runners and 774 randomly selected residents of Slovenia between the ages of 18 and 65 years. The data on the dietary habits of our subjects was gathered by means of two questionnaires. The following parameters were evaluated: the type of diet, a food pattern, and the frequency of consumption of individual food groups, the use of dietary supplements, fluid intake, and alcohol consumption. RESULTS: Recreational runners had better compliance with recommendations for healthy nutrition than the general population. This pattern increased with the runner's age and performance level. Compared to male runners, female runners ate more regularly and had a more frequent consumption of food groups associated with a healthy diet (fruit, vegetables, whole grain foods, and low-fat dairy products). The consumption of simple sugars and use of nutritional supplements by well-trained runners was inadequate with values recommended for physically active individuals. CONCLUSION: Recreational runners are an exemplary population group that actively seeks to adopt a healthier lifestyle.

Exercise-induced changes in iron status and hepcidin response in female runners.

BACKGROUND AND AIMS: Exercise-induced iron deficiency is a common finding in endurance athletes. It has been suggested recently that hepcidin may be an important mediator in this process. OBJECTIVE: To determine hepcidin levels and markers of iron status during long-term exercise training in female runners with depleted and normal iron stores. METHODS: Fourteen runners were divided into two groups according to iron status. Blood samples were taken during a period of eight weeks at baseline, after training and after ten days' recovery phase. RESULTS: Of 14 runners, 7 were iron deficient at baseline and 10 after training. Hepcidin was lower at recovery compared with baseline (p<0.05). The mean cell haemoglobin content, haemoglobin content per reticulocyte and total iron binding capacity all decreased, whereas soluble transferrin receptor and hypochromic red cells increased after training and recovery (p<0.05 for all). CONCLUSION: The prevalence of depleted iron stores was 71% at the end of the training phase. Hepcidin and iron stores decreased during long-term running training and did not recover after ten days, regardless of baseline iron status.

The effects of 8 weeks of endurance running on hepcidin concentrations, inflammatory parameters, and iron status in female runners.

Exercise-associated iron deficiency is a common disorder in endurance athletes. The authors investigated the effects of long-term endurance exercise on hepcidin concentrations, inflammatory parameters, and iron status in moderately trained female long-distance runners. Eighteen runners were assigned to either an interval- or a continuous-training exercise group. The physical training consisted of two 3-week progressive overload periods, each followed by a week's recovery, and concluded with a 10- or 21-km competitive run. Samples were taken 6 times during the 8-wk training program, first at baseline (BPre), then after the first and second 3-wk training loads (TPost1, TPost2), after each recovery week (Recovery1 and Recovery2), and poststudy (BPost). Soluble transferrin receptor (sTfR) concentrations were increased in Recovery2 and BPost compared with BPre (p=.02), hemoglobin decreased in TPost1 and TPost2 (p<.001), and red blood cells decreased in TPost2 (p=.01). Hepcidin decreased with time in TPost1 and in BPost compared with BPre (p<.001) and increased in TPost2 compared with TPost1 (p<.001). No differences over time were found for high-sensitivity C-reactive protein. The main findings of the current study indicate that serum hepcidin and sTfR were affected after 8 weeks of endurance running in women. No positive relation was found with inflammation.

Gender-related differences in maximum mechanical power output in short-term activities in children and adolescents.

The study was designed to examine the gender-related differences in maximum mechanical power output in various short-burst activities during growth. The subject sample consisted of four subgroups: 9 boys (14.11 +/- 0.6 yr), 9 boys (10.67 +/- 0.71 yr), 7 girls (14.29 +/- 0.49 yr), 7 girls (10.57 +/- 0.54 yr). We measured peak power (PP), mean power (MP), fatigue index (FI) during 30-s WAnT, squat jump height (SJH) and power (SJP), and counter movement jump height (CMJH) and power (CMJP), maximum speed over 20-metre distance (S20). Lactation concentration was measured in the 3rd and 5th minutes after the WAnT Ratio normalisation and ANCOVA were used to remove the influence of the differences in muscle (MM) and body mass (BM). Male adolescents had higher absolute values of PP (P < 0.05), MP (P < 0.05) than female. Ratio normalisation showed that boys had higher PP/BM (P < 0.05), PP/MM (P < 0.05), MP/BM (P < 0.05), MP/MM (P < 0.06) than girls. The ANCOVA adjustment for MM showed differences between genders in PP (P < 0.001), MP (P < 0.001), SJH (P < 0.05), SJP (P < 0.05) and CMJP (P < 0.001), whereas the ANCOVA adjustment for BM showed differences only in PP (P < 0.001), MP (P < 0.001). Prepubertal boys had higher absolute values only in SJP (P < 0.05). We concluded that variations in body composition could not be the only key to gender-related differences in power output in short-burst activities.

The effect of two warm-up protocols on some biomechanical parameters of the neuromuscular system of middle distance runners.

The objective of this study was to determine the effect of 2 different warm-up protocols on the neuromuscular system of well-trained middle distance runners. Seven runners performed 2 different warm-up protocols, one of which included slow running, stretching, and bounding and sprinting exercises, while the other consisted of slow running and stretching only. Before and after warm-up, contractile properties of the vastus lateralis and quadriceps femoris were monitored with a single twitch test, maximal torque, and the level of muscle activation during maximal voluntary extension. The 2 types of warm-up protocols showed statistically significant differences in the increase of peak knee extension torque and muscle activation level. After warm-up 1 maximal twitch torque was increased and twitch contraction time (CT) was shortened. Both maximal torque and the level of activation were increased. Parameter changes after warm-up 2 were similar to those after warm-up 1 but not statistically significant. Sprinting and bounding as part of athletes' warm-up improve muscle activation.