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Michelle S.M. Silva, Wladimir Bolani, Cleber R. Alves, Diogo G. Biagi, José R. Lemos Jr, Jeferson L. da Silva, Patrícia A. de Oliveira, Guilherme B. Alves, Edilamar M. de Oliveira, Carlos E. Negrão, José E. Krieger, Rodrigo G. Dias and Alexandre C. Pereira

Aim:

To study the relationship between the ACTN3 R577X polymorphism and oxygen uptake (VO2) before and after exercise training.

Methods:

Police recruits (N = 206, 25 ± 4 y) with RR (n = 75), RX (n = 97), and XX (n = 33) genotypes were selected. After baseline measures, they underwent 18 wk of running endurance training. Peak VO2 was obtained by cardiopulmonary exercise testing.

Results:

Baseline body weight was not different among genotypes. At baseline, XX individuals displayed higher VO2 at anaerobic threshold, respiratory compensation point, and exercise peak than did RR individuals (P < .003). Endurance training significantly increased VO2 at anaerobic threshold, respiratory compensation point, and exercise peak (P < 2 × 10−6), but the differences between XX and RR were no longer observed. Only relative peak VO2 exercise remained higher in XX than in RR genotype (P = .04). In contrast, the increase in relative peak VO2 was greater in RR than in XX individuals (12% vs 6%; P = .02).

Conclusion:

ACTN3 R577X polymorphism is associated with VO2. XX individuals have greater aerobic capacity. Endurance training eliminates differences in peak VO2 between XX and RR individuals. These findings suggest a ceiling-effect phenomenon, and, perhaps, trained individuals may not constitute an adequate population to explain associations between phenotypic variability and gene variations.

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Katrin A. Dias, Concetta E Masterson, Matthew P. Wallen, Arnt E. Tjonna, Mansoureh S. Hosseini, Peter S.W. Davies, Peter A. Cain, Gary M. Leong, Ross Arena, Charlotte B. Ingul and Jeff S. Coombes

Purpose:

Poor cardiorespiratory fitness is associated with increased all cause morbidity and mortality. In children with obesity, maximum oxygen uptake (V̇O2max) may not be achieved due to reduced motivation and peripheral fatigue. We aimed to identify a valid submaximal surrogate for V̇O2max in children with obesity.

Method:

Ninety-two children with obesity (7–16 years) completed a maximal exercise treadmill test and entered a three-month exercise and/or nutrition intervention after which the exercise test was repeated (n = 63). Participants were required to reach V̇O2max to be included in this analysis (n = 32 at baseline and n = 13 at both time-points). The oxygen uptake efficiency slope (OUES) was determined as the slope of the line when V̇O2 (L/min) was plotted against log V̇E. Associations between the maximal OUES, submaximal OUES (at 3, 4, 5 and 6 min of the exercise test) and V̇O2max were calculated.

Results:

In the cross-sectional analysis, V̇O2max (L/min) was strongly correlated with 5-min OUES independent of Tanner puberty stage and sex (R 2 = .80, p < .001). Longitudinal changes in V̇O2max were closely reflected by changes in 5-min OUES independent of change in percent body fat (R 2 = .63, p < .05).

Conclusion:

The 5-min OUES is a viable alternative to V̇O2max when assessing children with obesity.

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Michael J. Buono, Julia J. Roby, Frank G. Micale and James F. Sallis

The Astrand-Ryhming est was modified to overcome problems of predicting V̇O2max in children. V̇O2max was measured directly during a maximal treadmill test and estimated by means of a submaximal protocol in a test group of 51 subjects ages 10–18 years. A multiple regression equation was developed with directly measured V̇O2max as the dependent variable and age, body weight, and V̇O2max estimated from the Astrand nomogram as independent variables. The validity and reliability of this equation to predict V̇O2max in children and adolescents was cross-validated. No significant difference was found between the measured V̇O2max and that estimated from the equation. The correlation coefficient between measured and estimated V̇O2max for the cross-validation group was 0.89, with a standard error of estimate of 12%. Test-retest reliability was 0.95. It was concluded that this modification of the Astrand nomogram provides a valid and reliable prediction of V̇O2max in children and adolescents.

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Zhen-Bo Cao, Nobuyuki Miyatake, Tomoko Aoyama, Mitsuru Higuchi and Izumi Tabata

Background:

The purpose was to develop new maximal oxygen uptake (VO2max) prediction models using a perceptually regulated 3-minute walk test.

Methods:

VO2max was measured with a maximal incremental cycle test in 283 Japanese adults. A 3-minute walk test was conducted at a self-regulated intensity corresponding to ratings of perceived exertion (RPE) 13.

Results:

A 3-minute walk distance (3MWD) was significantly related to VO2max (r = .60, P < .001). Three prediction models were developed by multiple regression to estimate VO2max using data on gender, age, 3MWD, and either BMI [BMI model, multiple correlation coefficients (R) = .78, standard error of estimate (SEE) = 5.26 ml⋅kg-1⋅min-1], waist circumference (WC model, R = .80, SEE = 5.04 ml⋅kg-1⋅min-1), or body fat percentage (%Fat model, R = .84, SEE = 4.57 ml⋅kg-1⋅min-1), suggesting that the %Fat model is the best model [VO2max = 37.501 + 0.463 × Gender (0 = women, 1 = men) – 0.195 × Age – 0.589 × %Fat + 0.053 × 3MWD]. Cross-validation by using the predicted residual sum of squares (PRESS) procedures demonstrated a high level of cross-validity of all prediction models.

Conclusions:

The new VO2max prediction models are reasonably applicable to estimating VO2max in Japanese adults and represent a quick, low-risk, and convenient means for estimating VO2max in the field.

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Sonja de Groot, Linda J. Valent, Richard Fickert, Babette M. Pluim and Han Houdijk

Purpose:

To determine the relationship between outcomes of the shuttle wheel test (SWT) and peak oxygen uptake (VO2peak) during that test and whether SWT and VO2peak can discriminate between different skill levels of wheelchair tennis players.

Methods:

Fifteen wheelchair tennis players performed an SWT on a tennis court while VO2 was measured continuously. Outcome measures were VO2peak and achieved stage. Relations between outcomes and Dutch wheelchair tennis ranking were calculated with Spearman correlation. Independent t tests were used to test for differences between national and international players.

Results:

Moderate correlations were found between VO2peak and SWT outcome (r = .40–.47). The tennis ranking correlated weakly with VO2peak (r = –.35) and strongly with SWT outcome (r = –.80). A significant difference was found between national and international players for achieved stage (P = .027) and VO2peak (P = .027).

Conclusions:

The SWT outcome only explained a small part of the variance in VO2peak among players, so it cannot be considered a valid test for aerobic capacity. However, SWT outcomes are related to the skill level of the player and give a good indication of the overall peak wheelchair performance.

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Karin M. Allor and James M. Pivarnik

We calculated individual heart rate–oxygen consumption (HR–V̇O2) regression lines for 49 sixth-grade girls based on a treadmill test. From these data, we determined V̇O2 at HRs of 140 and 160 b · min−1 and 50%, 60%, and 75% of maximal heart rate reserve (MHRR), and the relationship between V̇O2 and %fat at given heart rates. Results indicated traditional 140 and 160 b · min−1 HR cutpoints were at the low end of exercise intensity (46 and 63% V̇O2max) and were negatively correlated with %fat. Heart rates at 50%, 60%, and 75% MHRR corresponded to 52%, 62%, and 76% of V̇O2max. Although the best method for analyzing HR data to describe physical activity intensity is unknown, use of 140 and 160 cutpoints may not describe vigorous or very hard exercise in adolescent girls as well as 75% MHRR. Researchers should also consider the effects of adiposity when using specific heart rate cutpoints.

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Martin Švehlík, Kryštof Slabý, Tomáš Trc̆ and Jir̆í Radvanský

The aim of the study is to investigate whether the net nondimensional oxygen utilization scheme is able to detect postoperative improvement in the energy cost of walking in children with cerebral palsy and to compare it with a body mass normalization scheme. We evaluated 10 children with spastic cerebral palsy before and 9 months after equinus deformity surgery. Participants walked at a given speed of 2 km/hr and 3 km/hr on a treadmill. Oxygen utilization was measured, and mass relative VO2 and net nondimensional VO2 were calculated. Coefficient of variation was used for the description of variability among subjects. Postoperatively, gait kinematics normalized and the mass relative VO2 and net nondimensional VO2 showed significant improvement. Net nondimensional VO2 is able to detect postoperative improvement with smaller variability among subjects than body mass related normalization in children with cerebral palsy.

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Neil Armstrong, Joanne Williams, John Balding, Peter Gentle and Brian Kirby

The peak oxygen uptake (VO2) of 199 boys and 164 girls (mean age 13.2±1.3 yrs) was examined in relation to their body fatness, blood pressure, and serum cholesterol level. Peak VO2 was significantly correlated with skinfold thickness in both sexes (range r = −0.41 to −0.56). When the common effects of skinfold thickness were removed, no significant relationships were observed between peak VO2 and either serum cholesterol or blood pressure. The habitual physical activity (HPA) of 92 boys and 132 girls (mean age 13.0+1.3 yrs) was examined in relation to their body fatness, blood pressure, and serum cholesterol. No significant relationships were observed. The results of this study indicate that although skinfold thickness is negatively related to peak VO2, favorable relationships between children’s peak VO2 or HPA and either blood pressure or serum cholesterol remain to be proven.

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Thomas J. O’Connor, Rick N. Robertson and Rory A. Cooper

Three-dimensional kinematic variables and their relationship to the physiology of racing wheelchair propulsion were studied. Six male wheelchair athletes performed two trials (medium and maximum speed) of 3 min each. VO2, VO2/kg, VE, and HR were measured. Results showed that at medium speed, wrist velocity on hand contact was significantly correlated with VO2/kg. At maximum speed, elbow velocity during preparatory phase was significantly correlated with VO2. Stepwise regression showed wrist trajectory angle and elbow velocity during preparatory phase were significantly correlated with VO2/kg. Results indicate that kinematic variables recorded prior to and on hand contact with the pushrim are significant variables in developing a more efficient racing wheelchair propulsion technique. Results of this study indicate a need to educate coaches of wheelchair track athletes concerning the best racing wheelchair propulsion technique.

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Jacinta M. Saldaris, Grant J. Landers and Brendan S. Lay

body mass 62.9 [7.8] kg, and VO 2peak 63.6 [4.4] mL·kg −1 ·min −1 ) participated in the study. Ethical approval was granted by the Human Research Ethics Office at the University of Western Australia (RA/4/1/8273). Informed written consent was obtained from all participants before their involvement in