The PWC170: comparison of different stage lengths in 11-16 year olds.
ABSTRACT It is unknown how the estimation of aerobic fitness in children and adolescents compares among physical working capacity (PWC) protocols with different stage lengths. The purpose of this study was twofold: (1) compare PWC tests with 2-, 3-, and 6-min stage lengths in youth, and (2) examine the relationship between PWC at a heart rate (HR) of 170 beats min(-1) (PWC170) and peak oxygen consumption (VO(2)peak). Fifty youth (31 m, 19 f), aged 11-16 years participated. Each participant visited the laboratory twice and performed three PWC tests (2-, 3-, 6-min stages) on a cycle ergometer. Tests usually consisted of three stages of increasing loads with the goal of reaching HR ≥ 165 beats min(-1). Individual regression lines were created to predict workload at HR = 170 beats ∙ min(-1) for each test. Participants completed two VO(2peak) tests, both running and cycling. Repeated measures ANOVA was used to compare PWC170 values. Pearson correlation was used to assess the relationships between VO(2peak) and power output for different PWC170 stage lengths. The three PWC170 protocols differ significantly; therefore, it is not advisable to directly compare results from different protocols. Furthermore, PWC170 showed moderate associations with VO(2peak), with the 2-min protocol showing the best correlation.
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ABSTRACT: The aim of this study was to examine possible discriminant physical and physiological characteristics between elite male handball players from elite teams with different league rankings. Players from three teams (A, B and C), which competed in the first league of the Greek championship during the season 2011-2012 participated in the study. Team A finished first, B came second and C came eighth out of eleven clubs. Teams A and B also participated in European Cups, and team A won the European Challenge Cup. The players (n=44) were examined for anthropometric characteristics and performed a series of physical fitness tests. Players from teams A and B were taller (6.2 cm (0.7;11.7), mean difference (95% CI) and 9.2 cm (4.0;14.5), respectively), and had a higher amount of fat free mass (6.4 kg (1.1;11.8) and 5.4 kg (0.2;10.5)) compared to those of team C. Players from team A performed better than players from team C in the squat jump (5.5 cm (1.0;10.0)), the countermovement jump without (5.5 cm (0.4;10.6)) and with arm-swing (6.0 cm (0.7;11.3)) and in the 30 s Bosco test (5.7 W·kg-1 (1.2;10.2)). Also, players from team A outperformed team B in mean power during the Wingate anaerobic test (WAnT, 0.5 W·kg-1(0;0.9)) and in the Bosco test (7.8 W·kg-1 (3.4;12.2)). Overall, players from the best ranked team performed better than the lowest ranked team on WAnT, vertical jumps and the Bosco test. Stepwise discriminant analysis showed that stature and mean power during the Bosco test were the most important characteristics in TH players, accounting for 54.6% of the variance in team ranking. These findings indicate the contribution of particular physical fitness components (stature, fat free mass and anaerobic power) to excellence in TH. In addition, the use of the Bosco test as an assessment tool in talent identification and physical fitness monitoring in this sport is further recommended.Journal of Human Kinetics 10/2013; 38:115-24. DOI:10.2478/hukin-2013-0051 · 0.70 Impact Factor
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ABSTRACT: To determine the feasibility of non-invasive evaluation of adrenal response in healthy prepubertal children by standardized exercise tests. On separate occasions, healthy prepubertal children performed a submaximal cycling test, a maximal cycling test, and a 20-m shuttle-run test. Salivary cortisol levels were determined before exercise, and 1 and 15 min after exercise. Immediately after cessation of the cycling and shuttle-run tests, salivary cortisol levels remained unchanged or decreased. Fifteen minutes after the shuttle-run test, salivary cortisol levels increased significantly. This increase in salivary cortisol levels was not observed 15 min after the cessation of the cycling tests. The results of this study demonstrate a different response in salivary cortisol levels after standardized cycling and running tests in prepubertal children. The increase in salivary cortisol levels found after a short standardized running test suggests that this may be a practical non-invasive method for evaluating adrenal response in healthy prepubertal children.Journal of pediatric endocrinology & metabolism: JPEM 06/2012; 25(5-6):471-8. DOI:10.1515/jpem-2012-0054 · 0.71 Impact Factor
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ABSTRACT: Cardiopulmonary exercise testing (CPET) is increasingly used as a biomarker of fitness in children. Maximal or peak values remain the most common variables obtained in CPET, but these physiologically challenging high-intensity work rates are often not achieved. We hypothesized that interactions of gas exchange, heart rate (HR), and work rate (WR) CPET variables (slopes) could yield useful mechanistic and clinical insights that might enhance the clinical utility of CPET in children. We further hypothesized that the dependence of the slope on body mass could be predicted by first-principle analysis of body size and physiological response. One hundred sixty-nine healthy participants (8-18 years old, BMI < 95 percentile, 82 females) underwent dual X-ray absorptiometry scan to estimate lean body mass (LBM) and performed a ramp-type progressive cycle ergometry exercise protocol with breath-by-breath measurement of gas exchange. Linear regression was used to calculate the slopes among V˙O2, V˙CO2, V˙E, HR, and WR. [INCREMENT]WR/[INCREMENT]HR (r = 0.87) and [INCREMENT]V˙O2/[INCREMENT]HR (r = 0.96) were strongly correlated with peak V˙O2, while [INCREMENT]V˙O2/[INCREMENT]WR (r = 0.42) and [INCREMENT]V˙E/[INCREMENT]V˙CO2 (r = - 0.51) were mildly correlated with peak values. LBM was more highly correlated than was total body mass with those slopes predicted to be body size dependent (p < 0.0001). The data largely supported our original hypotheses. Unlike peak or maximal values, which are derived from no more than a few data points at the end of a progressive exercise test, the CPET slopes were calculated from a much larger data set obtained throughout the test. Analysis of these slopes might ultimately prove useful clinically and in research studies when peak values are not achieved.Medicine and science in sports and exercise 10/2013; 46(5). DOI:10.1249/MSS.0000000000000180 · 4.46 Impact Factor