BACKGROUND: The lockdown measures related to coronavirus disease 2019 (COVID) impacted the health of adolescents by reducing physical activity (PA). The physical changes in response to decreases in PA can be measured with full body composition analysis. The aim of this study was to evaluate the effects of long-term PA restrictions on body fat (BF), fat-free mass (FFM) and skeletal muscle mass (SMM) in adolescents. METHODS: A total of 1669 boys (before PA restriction (G1): 998; after PA restrictions ended (G2): 671; between the ages of 11 and 18 were included. The measured parameters were body mass (BM), visceral fat area (VFA), BF, FFM and SMM. The whole-body composition was evaluated using bioelectrical impedance analysis (BIA). RESULTS: Compared to G1, G2 exhibited an increase in BF between 1.2 and 5.1%. This difference was significant in boys aged 13 to 18 years (p < 0.05). VFA increased between 5.3 and 20.5 cm2; this increase was significant in boys aged 13 to 18 years (p < 0.05). SMM decreased between 2.6 and 3.8%, and this decrease was significant in all age groups (p < 0.05). Changes in body composition were not accompanied by any significant changes in BM. CONCLUSIONS: COVID-19 restrictions reduced PA, resulting in a significant decrease in SMM. This decrease may impact boys' ability to engage in sufficiently varied PA, which may lead to a further decline in PA and subsequent medical consequences in adulthood.
- Klíčová slova
- Body fat, Body mass, Fat-free mass, Physical activity restriction, Skeletal muscle mass, Visceral fat,
- MeSH
- COVID-19 * epidemiologie MeSH
- dítě MeSH
- dospělí MeSH
- kontrola infekčních nemocí MeSH
- lidé MeSH
- mladiství MeSH
- složení těla MeSH
- tuková tkáň MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika epidemiologie MeSH
Chronic airflow limitation, caused by chronic obstructive pulmonary disease (COPD) or by asthma, is believed to change the shape and the position of the diaphragm due to an increase in lung volume. We have made a comparison of magnetic resonance imaging (MRI) of diaphragm in supine position with pulmonary functions, respiratory muscle function and exercise tolerance. We have studied the differences between patients with COPD, patients with asthma, and healthy subjects. Most interestingly we found the lung hyperinflation leads to the changes in diaphragmatic excursions during the breathing cycle, seen in the differences between the maximal expiratory diaphragm position (DPex) in patients with COPD and control group (p=0.0016). The magnitude of the diaphragmatic dysfunction was significantly related to the airflow limitation expressed by the ratio of forced expiratory volume in 1 s to slow vital capacity (FEV(1)/SVC), (%, p=0.0007); to the lung hyperinflation expressed as the ratio of the residual volume to total lung capacity (RV/TLC), (%, p=0.0018) and the extent of tidal volume constrain expressed as maximal tidal volume (V(Tmax)), ([l], p=0.0002); and the ratio of tidal volume to slow vital capacity (V(T)/SVC), (p=0.0038) during submaximal exercise. These results suggest that diaphragmatic movement fails to contribute sufficiently to the change in lung volume in emphysema. Tests of respiratory muscle function were related to the position of the diaphragm in deep expiration, e.g. neuromuscular coupling (P(0.1)/V(T)) (p=0.0232). The results have shown that the lung volumes determine the position of the diaphragm and function of the respiratory muscles. Chronic airflow limitation seems to change the position of the diaphragm, which thereafter influences inspiratory muscle function and exercise tolerance. There is an apparent relationship between the position of the diaphragm and the pulmonary functions and exercise tolerance.
- MeSH
- bránice patofyziologie MeSH
- bronchiální astma patofyziologie MeSH
- chronická obstrukční plicní nemoc patofyziologie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- respirační funkční testy MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
AIM: The aim of this study was to investigate multiple regression models with prediction equations that would enable a valid estimate of running repeated-sprint ability (RSA) in soccer players from the variables measured in field and laboratory physiological tests. METHODS: Adolescent soccer players (N=33) performed five field performance tests and two laboratory tests for assessment of muscle strength of legs, sprint ability, anaerobic power and capacity, aerobic power and capacity, and running economy. These tests served as potential predictors of RSA. RSA was assessed by a intermittent anaerobic running test (IAnRT) consisted of ten 20 m sprints. RESULTS: Multiple regression analysis revealed that the mean speed in the 20 m sprint test and the 2 km endurance running test accounted for 89% of total variation in the mean running speed in the IAnRT (VIAnRT) as the indicator of capacity for multiple sprint work (R2=0.89, SEM=0.09 m.s-1). Using the variables from the laboratory tests, the best prediction of the VIAnRT was obtained from the running speed at the ventilatory threshold level (VVT) and anaerobic power (Pmax.kg-1) (R2=0.49, SEM=0.21 m.s-1). CONCLUSION: Performance in the multiple-sprint exercise as an indicator of RSA can be estimated by the regression equation with two predictors - mean speed in the 20 m sprint and 2 km running test with an error of 4%.
BACKGROUND: Increases in juvenile overweight and obesity have emphasized the importance of accurate and accessible body composition (BC) assessment, namely for the monitoring, prevention and treatment. Bioimpedance analysis seems to be one of the simple, safe, and inexpensive methods for assessment of the body composition in paediatric subjects METHODS AND RESULTS: Three-thousand-twelve children aged 6-14 years (1611 - 53.5 % boys, and 1401 - 46.5 % girls) were evaluated BC using mono frequency and multi-frequency bioimpedance analyser with adapted prediction equation for Czech children. In both genders %BF decreased significantly with age (r = -0.698 in boys and r = -0.681 in girls, both p<0.0005). Linear regression analysis showed a significant positive relationship between %BF measured with BMI %BF(%)= 0.921*BMI(kg.m(-2)) -4.292, r = 0.858, r(2) = 0.736, SEE = 1.22 % in boys, and in girls %BF(%) = 1.284*BMI(kg.m(-2)) - 6.906, r = 0.903, r(2) = 0.815, SEE = 1.05 %, p<0.0001 in both cases. CONCLUSIONS: BIA method is a useful method for detecting BC in children and can be accepted as a precise tool for measuring of BC in epidemiological studies in children. The decisive role for the use of this method has the population oriented prediction equation and the subject's hydration state.
- MeSH
- dítě MeSH
- elektrická impedance MeSH
- lidé MeSH
- mladiství MeSH
- složení těla * MeSH
- tělesná voda MeSH
- tuková tkáň MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
BACKGROUND: During chronic renal failure, number of complex metabolic and endocrinal changes in organism can develop, which in consequence lead to an inception of associate complications and in principle change the activity of all organ systems. Functional capacity of the chronically dialysed patients is limited, muscle strength is decreased, joint mobility is limited and the muscular imbalance is frequently found. According to the recent literature, an acceptable choice of exercise activity could contribute to prevention of disturbances and improve the patient's status. An essential part of each exercise program for these patients is an acceptable motor tests battery (1, 2, 3, 4, 5, 6 and 7). The aim of our study was to choose an acceptable motor tests battery, which should target such components of motor performance, whose certain rate is necessary for self-sufficiency keeping and perform activities of daily living. METHODS AND RESULTS: We observed mixed group of 23 patients. For evaluation of the functional condition we used the "Senior Fitness Test Manual" (8), which measures these physical attributes: muscle strength, physical endurance, flexibility, agility and balance. The input results we compared with population standard specification used in the test battery. Results of the tests showed that the group of patients in comparison with the population standard specification have reached subnormal and risk performances, especially in tests requiring for its implementation muscular strength of lower extremities and physical efficiency. Normal and above normal performances we observed in patients that were physically active before and during regular dialysis treatment. CONCLUSIONS: After the evaluation of result, we consider the selected battery of motor tests as an acceptable choice for motor skills testing in renal dialysed patients all age categories.
- MeSH
- chronické selhání ledvin patofyziologie terapie MeSH
- dialýza ledvin MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- posuzování pracovní neschopnosti MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- tělesná výkonnost * MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
BACKGROUND: Both the high body fatness and low aerobic fitness have been shown to be risk factors for cardiovascular disease and type 2 diabetes. It is still unclear, whether these factors are related to each other or if they are independent risk factors. The objective of this study was to assess the influence of body composition on aspects of aerobic fitness in obese women. METHODS AND RESULTS: Relative body fat was measured in a group of 31 obese women differing in age (25-54 years) by dual energy X-ray absorbtiometry (DEXA), in range of 40,8-58,8% of the body fat. Intracellular and extracellular fractions of the fat free mass were assessed by bioimpedance analysis. Maximal power output and maximal oxygen consumption were measured by stepwise load test on bicycle ergometer. Mean values of absolute and relative VO2max expressed per kg body mass and per kg fat-free mass were 2,09+/-0,38 l x min(-1), 22,82+/-3,79 ml x min(-1) kg(-1), and 44,05+/-7,03 ml x min(-1) x kg(-1), respectively. Absolute VO2max was positively related to body weight (R=0,4758; P<0,01), BMI (R=0,5004; P<0,01), fat-free mass (R=0,5138; P<0,01) and body cell mass (R=0,4983; P<0,01). No significant dependence of relative VO2max per kg body mass on the body fat was identified. CONCLUSIONS: Aerobic fitness, expressed by relative maximal oxygen consumption per kg of body weight, is not influenced by the percent of body fat in obese women. Body cell mass is markedly related to aerobic fitness, expressed by absolute maximal oxygen consumption in obese women.
- MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- obezita patofyziologie MeSH
- složení těla * MeSH
- spotřeba kyslíku * MeSH
- tělesná výkonnost * MeSH
- tolerance zátěže MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
BACKGROUND: Bioimpedance analysis (BIA) is often used for the assessment of relative body fat (%BF). The accuracy of the test depends on prediction equation used, which respects the group of population, body composition, age and gender of the individual. The requirement to construct a specific prediction equation for obese population with more than 30% body fat was suggested. The objective of the study was to evaluate the validity of bioimpedance analysis and to develop population-specific prediction equation for obese women. METHODS AND RESULTS: Relative body fat were measured in set of 63 obese women by means of 3 methods: tetrapolar bioimpedance analysis, bipedal bioimpedance analysis and dual energy X-ray absorbtiometry (DEXA). Significant differences were found among mean values of %BF measured by methods above (39.9%, 42.2% and 48.7%, respectively). Significant correlation between results obtained by tetrapolar BIA and by DEXA method was noticed (R=0.73). New specific prediction equation was developed for measuring %BF of obese women by tetrapolar BIA. No good agreement between bipedal BIA and DEXA method was found. CONCLUSIONS: By using the new prediction equation, measurement of the relative body fat in obese women by tetrapolar bioimpedance analysis was comparable with the reference DEXA method.
- MeSH
- absorpční fotometrie MeSH
- dospělí MeSH
- elektrická impedance MeSH
- lidé středního věku MeSH
- lidé MeSH
- obezita diagnóza patologie MeSH
- složení těla * MeSH
- tuková tkáň patologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
BACKGROUND: There is still much uncertainty and debate surrounding the physiological requirements of competitive soccer. The coaching emphasis on skill development, deficiencies in fitness training, conservative training methods lead to difficulty in the scientific study of soccer. METHODS: The physiological profiles of 22 young soccer players (mean age = 8.0+/-0.3 years, body mass = 28.2+/-3.2 kg, body height = 132.4+/-4.3 cm and body fat = 19.4+/-1.6 percent) were measured by the incremental exercise protocol on the treadmill with 5 percent inclination. All boys systematically trained at least 2 years with a minimum of two training units per week. During preseason, they trained two times per week, and during the competitive season they trained at least three times and competed in one or two games per week. RESULTS: Mean VO2max x kg(-1) was 56.7+/-4.9 ml x kg(-1) x min(-1). Mean value of maximal running speed on a treadmill with 5 percent of inclination was 12.0+/-0.9 km x h(-1). Mean values of Rmax = 1.11+/-0.07. The selected functional variables at the ventilatory threshold (VT) level corresponded to VO2 x kg(-1) = 42.9+/-5.0 ml x kg(-1) x min(-1), mean values of percent VO2max x kg(-1) at VT level were 76.5+/-1.3 percent, mean speed of running was 10.5+/-1.2 km x h(-1), mean values of percent Vmax at VT level were 87.5+/-1.9 percent. The mean of energy cost of running was 4.28+/-0.19 J x kg(-1) x m(-1). According to our results, we can conclude that the physiological characteristics of young soccer players about 8 years old should be as follows: VO2max x kg(-1) higher than 55 ml x kg(-1) x min(-1) in defenders, and higher than 60 ml x kg(-1) x min(-1), in midfielders and forwards. Maximal speed of running on the treadmill with 5 percent of inclination should be higher than 12 km x h(-1) in all players, the running speed at anaerobic threshold (5 percent) higher than 10.5 km x h(-1), percent VO2max at anaerobic threshold level higher than 77.0 percent, and the energy cost of running lower than 4.20 J x kg(-1) x m(-1). CONCLUSIONS: As in other sports where skills play a decisive role, the physiological data cannot be the sole predictor of competitive success. On the other hand, we must note that these physiological norms and standards are necessary conditions for success in high levels of soccer competition. The norms play decisive role in talent selection.
- MeSH
- anaerobní práh fyziologie MeSH
- antropometrie * MeSH
- dítě MeSH
- dospělí MeSH
- energetický metabolismus MeSH
- fotbal fyziologie MeSH
- index tělesné hmotnosti MeSH
- lidé MeSH
- lineární modely MeSH
- respirační funkční testy MeSH
- spotřeba kyslíku fyziologie MeSH
- tuková tkáň anatomie a histologie MeSH
- zátěžový test MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: The energy demands of movement may be characterised by the energy cost C, which indicates how much energy is needed to carry a body mass of 1 kg over a distance of 1 m. It is generally accepted that the lower C represents a lesser amount of mechanical work executed with the same efficiency. The purpose of this study was to assess the influence of body fat on energy cost of running in healthy non-trained females. METHODS: Energy cost of running (C) was determined on the treadmill in a group of healthy non-trained females (N=63, mean age=39.+/-10.2 years, body mass=64.6+/-5.5 kg, height= 166.2+/-5.7 cm, VO2max.kg(-1)=35.0+/-3.6 ml.kg(-1)min(-1)), differing significantly in the percentage of body fat (18.9-30.2%), assessed by the 10 skinfold measurements. RESULTS: Mean value of C was 3.97+/-0.07 J.kg(-1)m(-1). The lowest values of C were found in subjects with the lowest %BF (C ranged from 3.81 to 4.06 J.kg(-1).m(-1)). There is a significant positive correlation between C and %BF [C (J.kg(-1).m(-1))= 0.0185*%BF (%) + 3.5090; r=0.7805; p<0.001; r2=0.6091], C and body mass (BM) [C (J.kg(-1).m(-1)) = 0.0083*BM (kg) + 3.4384; r=0.6176; p<0.001; r2 = 0.3814], and C and free fat mass (FFM) [C (J.kg(-1).m(-1))=0.0087*FFM (kg) + 3.5543; r=0.3521; p<0.05; r2=0.1240]. There is a negative correlation between C and VO2max.kg(-1) [C (J.kg(-1).m(-1))=-0.0181* VO2max.kg(-1) (ml.kg(-1).min(-1)) +4.6071; r=-0.8810; p<0.0001; r2=0.7761], and VO2max.kg(-1) and %BF [VO2max.kg(-1) (ml.kg(-1).min(-1)) =-0.8401* %BF(%) + 54.1021; r=-0.7142; p<0.0001; r2=0.5101]. CONCLUSIONS: From the collected data for untrained females we may conclude: first, the higher the training state (VO2max.kg(-1)), the lower the energy cost of running. Second, the energy cost of running C increases with the increase in body mass, %BF and FFM. Third, the training state decreases (VO2max.kg(-1)) with the increase in %BF.
- MeSH
- běh fyziologie MeSH
- dospělí MeSH
- energetický metabolismus * MeSH
- lidé středního věku MeSH
- lidé MeSH
- mechanika dýchání MeSH
- složení těla * MeSH
- spotřeba kyslíku MeSH
- tuková tkáň MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Walking is a basic activity in visually handicapped subjects, and often it is used as a general means of improving physical fitness. The level of adaptation to walking may be assessed by means of energy cost, c. The variable c was studied during walking on a treadmill in two groups of visually handicapped children (international classification of vision of 5/200 or less). The two groups were comprised of 15 boys (mean age = 11.8 +/- 2.1 years) and 13 girls (mean age = 11.6 +/- 3.1 years). The mean energy cost in boys was found to be 3.79 +/- 0.31 J kg(-1) m(-1) and in girls it was 3.77 +/- 0.36 J kg(-1) m(-1). Both these values were not significantly higher than the energy cost in untrained nonhandicapped children of the same age. There was a U-shaped dependence of c on increased speed of walking. The minimum was about 3.6 km h(-1) in both groups of handicapped children, which was similar to that for non-handicapped subjects. It is concluded that in visually handicapped children the energy cost of walking, and thus adaptation to walking, is the same as in the healthy children. The visually handicapped individuals show a 'normal' response to exercise, to which they are adapted, with increases in both cardiovascular and muscular fitness.
- MeSH
- chůze fyziologie MeSH
- dítě MeSH
- fyziologická adaptace MeSH
- lidé MeSH
- mladiství MeSH
- poruchy zraku * MeSH
- spotřeba kyslíku MeSH
- tělesná výkonnost MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
