1,720,979 research outputs found
Breath-by-breath estimate of alveolar gas transfer variability in man at rest and during exercise
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Effects of short-term, integrated body mass reduction program on maximal oxygen consumption and anaerobic alactic performance in obese subjects
No full textThe study investigated the effect of a short-term (3-week) body mass reduction program, combining energy-restricted diet, nutritional education, psychological counselling and aerobic exercise training (DEP-AT) on maximal oxygen consumption (VO2max) and anaerobic alactic performance evaluated with different techniques in obese patients (grade II and III). Fifty-three (14 males, 39 females) obese subjects [average±SD body mass index (BMI): 41.6±4.2 kg/m2] were tested before and after the DEP-AT program characterised by a daily conditioning protocol of aerobic exercise on cycloergometer, treadmill and armergometer for a total duration of 35 min at an intensity corresponding to 50% of individual VO2max during the first week of the program and at 60% in the following 2 weeks. VO2max was determined with the cycloergometric indirect method. Short-term alactic anaerobic performance was evaluated with: a) jumping test (5 consecutive jumps with maximal effort, Bosco technique), b) short sprint running test (8 m), and c) stair climbing test (modified Margaria test). The DEP-AT program induced a significant weight loss (-4.57±1.26%, p<0.001) and a significant ̇VO2max increase (14.1±20.5%, p<0.001). After the DEP-AT program, lower limb alactic anaerobic power output, calculated on a per kg body mass basis, increased significantly both in jumping and in stair climbing (20.1±24.8%, p<0.001 and 13.5±19.75%, p<0.001, respectively), as well as average horizontal velocity during short sprinting (7.2±17.6%, p<0.01 . Power output was a major determinant of the motor performance, being significantly correlated with: a) vertical displacement of the centre of gravity (R2=0.884, p<0.001) in jumping test, b) vertical velocity (R2=0.348, p<0.001) in stair climbing test, and c horizontal velocity (R2=0.394, p<0.001) in short running test. In conclusion, short-term DEP-AT program induces significant improvements in both aerobic capabilities and anaerobic performance, possibly through the combination of a number of contributory mechanisms, such as exercise-mediated training, shift in the balance between parasympathetic and sympathetic activity, a weight-loss dependent shift toward a more favourable region of the muscle power-velocity curve, acquisition of a certain degree of motor skill during the conditioning program, improvement of self-esteem and motivation. © 2003, Editrice Kurtis
The impact of gender, body dimension and body composition on hand-grip strength in healthy children
No full textMaximum hand-grip (HG) strength, body composition and main anthropometric variables were evaluated in 278 children with normal weight and growth, aged 5-15 yr divided into 3 age groups: group 1, age+/-SD: 7.6+/-0.9 yr 7.6+/-0.9 SD (Tanner stage 1); group 2, age: 10.8+/-0.7 yr (Tanner stage: 2-3); group 3, age: 13.2+/-0.9 yr (Tanner stage: 4-5). Weight, height, body surface area (BSA), BMI, percent body fat (BF) and fat free mass (FFM) increased progressively and significantly from the younger to the older age group. A significant difference between genders was detected only for BF and FFM, females having a higher fat mass and a lower FFM compared to males. Most children were right-handed (91%). In either genders, a curvilinear relation was detected between HG strength and age, with best fit for the dominant (d) hand given by the equations: dHG=5.891 *10(0.051) age, r2=0.986, p<0.001 in males and dHG=6.163 *10(0.045) age r2=0.973, p<0.001 in females. The increase in HG strength after 11 yr appears to be steeper in males as compared with that found in females. In both d and non-dominant (nd) hand, a significant difference in HG strength was detected between males and females, the average difference being about 10% at all ages. For both genders, nd hand was significantly weaker than d hand in the older age groups (2 and 3), but not in the younger group 1. Age and gender-dependent differences in HG strength (but not differences between d and nd hand) disappear if HG strength is normalized for FFM. Thus, in general, dHG strength normalized for FFM resulted on average to be 0.67+/-0.11 kg/kg. A multiple linear regression analysis indicated that HG was positively correlated with BMI, BSA, stature, stature2 and FFM (p<0.001 for all correlations) without differences between genders, while a negative correlation was found between HG strength and %BF. The most significant correlation was found between HG strength and FFM, without any significant difference between genders, so that the overall equation describing the line for the d hand was: dHG strength= 2.32+0.63 FFM, r2=0.72, p<0.001. In conclusion, the present study indicates that the age-dependent increase of HG strength as well as the between-gender differences are strongly related to changes of FFM values occurring during childhood. Moreover, the study provides a standard normative value of maximal HG strength for the healthy children population in Northern Italy
Locomotor behaviours and respiratory pattern of the Mediterranean fin whale (Balaenoptera physalus).
No full textEffects of low- and high-intensity exercise training on body composition and substrate metabolism in obese adolescents
No full textThe objective was to investigate the effects of a 3- week weight-management program including moderate energy restriction and exercise training at 2 intensities [low intensity (LI): 40% and high intensity (HI): 70% maximal oxygen uptake (V'O(2)max)] on body composition, energy expenditure, and fat oxidation rate in severely obese adolescents. Twenty obese adolescents, aged 15-17 yr (body mass index: 37.5 kg/m(2); 38.2% fat mass) participated in this study. Before starting (week 0, W0) and at the end of the weight-management period (week 3,W3), body composition was assessed by a multifrequency tetrapolar impedancemeter; basal metabolic rate (BMR), energy expenditure, and substrate oxidation rate during exercise and post-exercise recovery by indirect calorimetry. At W3, body mass and fat mass decreased significantly (p<0.005) in all groups, and the decreases were significantly greater in the LI than in the HI group (-8.1±1.6 vs -5.9±1.6 kg and -4.2±1.9 vs -2.3±1.7 kg, p<0.05, respectively). Predicted V'O(2)max, expressed in relative values, changed significantly only in the HI group by +0.010±0.006 l/(kg fat-free mass × min) (p=0.010). By contrast, no significant changes were observed at W3 in BMR, energy expenditure, and substrate oxidation rate during exercise and post-exercise recovery. In conclusion, LI (40% of V'O(2)max) physical activity favors fat oxidation and it seems advisable to encourage obese adolescents to perform LI physical activity which is more feasible and acceptable than intense exercis
Fat oxidation rate during and after a low- or high-intensity exercise in severely obese Caucasian adolescents.
No full textThe objective is to study the effects of low-intensity (LI) or high-intensity (HI) equicaloric exercises on energy expenditure (EE) and substrate oxidation rate during and after the exercises in severely obese Caucasian adolescents. Twenty obese boys (BMI-SDS 3.04 +/- 0.52, %Fat Mass 38.2 +/- 2.1%) aged 14-16 years (pubertal stage >3) participated in this study. Maximal oxygen uptake (V'O(2max)) and maximal fat oxidation rate were determined with indirect calorimetry using a graded exercise test on a treadmill. EE and substrate oxidation rate during equicaloric low-intensity (LI, 42% V'O(2max) for 45 min) and high-intensity (HI, 67% V'O(2max) for 30 min) exercises on a treadmill and during post-exercise recovery period (60 min) were determined with indirect calorimetry. Maximal fat oxidation rate was observed at 42 +/- 6% V'O(2max) (62 +/- 5% HR(max)) and fat oxidation rate was 0.45 +/- 0.07 g/min. The total amounts of EE, during the LI and HI exercises, and the post-exercise recovery periods were not significantly different (1,884 +/- 250 vs. 1,973 +/- 201 kJ, p = 0.453), but the total amount of fat oxidised was significantly higher (+9.9 g, +55.7%, p < 0.001) during the LI exercise than during the HI exercise. However, fat oxidation rates during the post-exercise recovery periods were not significantly different following LI and HI exercises. Total fat oxidised was significantly higher during the LI than during the HI exercise in obese adolescents. However, the equicaloric exercise intensity did not influence EE, fat and carbohydrate oxidation rate during the recovery period
Short-term effects of exercise on body water distribution of severely obese subjects as determined by bioelectrical impedance analysis
No full textWe have previously shown that a short-term weight (Wt) reduction programme consisting of energy restriction, physical activity and psychological counselling, produces physiological changes of body water distribution (BWD) in obese subjects as detected by bioelectrical impedance analysis. The present study was aimed at testing the contribution of diet and physical activity to the observed changes in BWD. A number of 96 obese inpatients were consecutively enrolled in the study at our Obesity Clinic. During a 3-wk period, they underwent a body Wt reduction programme comprising the same dietary strategy and psychological counselling. The programme differed as far as physical activity is concerned, with 52 subjects randomized to a baseline exercise programme (BEP), 22 to a cardiovascular exercise programme (CEP) and 22 to a cardiovascular and strength programme (CSP). Absolute and percent Wt reduction was significantly higher in CSP than BEP subjects (p<0.05) and the same hold for the changes in impedance (Z) at frequencies of 5, 50 and 100 kHz (P<0.05). The change in the Z(5)/Z(100) ratio did not show however any between-group difference (p=NS). The average values of Z changes were 1.5 to 2 times higher in CEP and 5.0 to 5.5 times higher in CSP than BEP subjects. We conclude that the type of exercise performed does influence the absolute changes of total body water and extracellular water but not BWD in severely obese subjects undergoing Wt loss
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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