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David M. Shaw, Fabrice Merien, Andrea Braakhuis, Daniel Plews, Paul Laursen and Deborah K. Dulson

least 12 months and without a history of recurrent gastrointestinal symptoms volunteered to participate in the study (age, 26.7 ± 5.2 years; body mass, 69.6 ± 8.4 kg; height, 1.82 ± 0.09 m; body mass index, 21.2 ± 1.5 kg/m 2 ; VO 2 peak, 63.9 ± 2.5 ml·kg −1 ·min −1 ; W max,  389.3 ± 50.4 W; hours

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Scott E. Crouter, Paul R. Hibbing and Samuel R. LaMunion

criterion measure. The oxygen consumption (VO 2 ) data were averaged over one-minute periods and converted to EE (MET y  = activity VO 2 divided by measured RMR). A cutoff of <1.5 MET y was used to identify minutes of SB. All minutes of the free-living measurement were used, except when the mask was

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Carl Foster, Jos J. de Koning, Christian Thiel, Bram Versteeg, Daniel A. Boullosa, Daniel Bok and John P. Porcari

 min at 5 km·hr −1  + 1.5 km·hr −1 per minute until 9.5 km·hr −1 , then 0.8 km·hr −1 until fatigue) in the laboratory with measurement of respiratory gas exchange (CPET; COSMED, Rome, Italy) to allow the determination of VO 2 peak. The pretraining and posttraining 10-km performances were conducted as

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Don W. Morgan, Wayland Tseh, Jennifer L. Caputo, Ian S. Craig, Daniel J. Keefer and Philip E. Martin

The purpose of this study was to quantify running economy (RE) during level treadmill running in 6-year-old children and to identify the potentially mediating effects of resting oxygen uptake and body fat percentage on sex differences in RE. Resting oxygen uptake (VO2), body fat, and RE at 5 mph were quantified in 15 boys and 20 girls following 30 min of treadmill accommodation. While absolute VO2 and mass-related values of gross and net VO2 were significantly higher in boys compared to girls, gross VO2 expressed relative to fat-free mass was not different between sexes. These results indicate that 6-year-old girls exhibit better RE compared to 6-year-old boys when VO2 is expressed as a function of total body mass. This sex difference in VO2 may reflect an increase in aerobic energy demands associated with the presence of a greater muscle mass in boys.

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Anthony D. Mahon and Paul Vaccaro

Whether the point of deflection from linearity of heart rate (HRD) coincides with ventilatory threshold (VT) has not been extensively examined in children. The purpose of this study was to assess the relationship between the VO2 measured at VT and the VO2 measured at HRD. Twenty-two boys with a mean age of 10.7 years (±1.0) performed a graded exercise test to determine VT, HRD, and VO2max. There was no significant difference between mean VO2 (ml/kg/min) at VT and at HRD (33.5±3.5 vs. 34.1±4.4; p>0.05). Linear regression analysis revealed a correlation of r = 0.76 (p<0.01) between the VO2 measured at VT and the VO2 measured at HRD. These results indicate that HRD may be an accurate predictor of VT in most but not all children, and caution should be used when interpreting the significance of HRD.

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Neil Armstrong and Joanne R. Welsman

Over 60 years ago, Robinson published the first investigation of boys’ aerobic fitness; almost 50 years ago, Åstrand conducted his pioneering studies of both sexes. Twenty four percent of the papers published during the first 10 years of Pediatric Exercise Science (1989-98) involved the determination of peak V̇O2. Yet, the interpretation of aerobic fitness during childhood and adolescence is still shrouded with controversy. In this paper we review peak V̇O2 in relation to age, growth, maturation, and sex. We describe the increase in peak V̇O2 with age, challenge the traditional interpretation of peak V̇O2 during growth, demonstrate the independent contribution of maturation to peak V̇O2, and address the progressive divergence of boys’ and girls’ peak V̇O2, during childhood and adolescence.

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Stamatis Agiovlasitis, Jeffrey A. McCubbin, Joonkoo Yun, Michael J. Pavol and Jeffrey J. Widrick

This study examined whether the net rate of oxygen uptake (VO2net) and the net oxygen uptake per kilometer (VO2net/km) are affected during walking in adults with Down syndrome (DS) and whether their preferred walking speed (PWS) minimizes the VO2net/km. Respiratory gases were collected as 14 adults with DS and 15 adults without DS completed a series of treadmill walking trials. PWS was measured over 15 meters in a hallway. The VO2net and the VO2net/km were higher in adults with DS than adults without DS. The overground PWS normalized for leg length was the same for both groups and did not appear to minimize the VO2net/km. Thus, adults with DS are less economical during walking than adults without DS. The overground PWS does not minimize the metabolic cost during treadmill walking.

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Espen Tønnessen, Erlend Hem, Svein Leirstein, Thomas Haugen and Stephen Seiler

Purpose:

The purpose of this investigation was to quantify maximal aerobic power (VO2max) in soccer as a function of performance level, position, age, and time of season. In addition, the authors examined the evolution of VO2max among professional players over a 23-y period.

Methods:

1545 male soccer players (22 ± 4 y, 76 ± 8 kg, 181 ± 6 cm) were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2012.

Results:

No differences in VO2max were observed among national-team players, 1st- and 2nd-division players, and juniors. Midfielders had higher VO2max than defenders, forwards, and goalkeepers (P < .05). Players <18 y of age had ~3% higher VO2max than 23- to 26-y-old players (P = .016). The players had 1.6% and 2.1% lower VO2max during off-season than preseason (P = .046) and in season (P = .021), respectively. Relative to body mass, VO2max among the professional players in this study has not improved over time. Professional players tested during 2006–2012 actually had 3.2% lower VO2max than those tested from 2000 to 2006 (P = .001).

Conclusions:

This study provides effect-magnitude estimates for the influence of performance level, player position, age, and season time on VO2max in men’s elite soccer. The findings from a robust data set indicate that VO2max values ~62–64 mL · kg−1 · min−1 fulfill the demands for aerobic capacity in men’s professional soccer and that VO2max is not a clearly distinguishing variable separating players of different standards.

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Glen E. Duncan, Anthony D. Mahon, Julie A. Gay and Jennifer J. Sherwood

Physiological and perceptual responses at ventilatory threshold (VT) and V̇O2 peak were examined in 10 male children (10.2 ± 1.3 yrs) during graded treadmill and cycle exercise. Treadmill V̇O2peak (57.9 ± 6.7 ml · kg−1 · min−1) was higher (p < .05) than the cycle (51.7 ± 7.7 ml · kg−1 · min−1). Ventilation and heart rate (HR) were higher (p < .05) on the treadmill, while respiratory exchange ratio (RER), rating of perceived exertion (RPE), capillary blood lactate, and test duration were similar between tests. The V̇O2 at VT was higher (p < .05) on the treadmill (36.7 ± 4.6 ml · kg−1 · min−1) than the cycle (32.5 ± 4.4 ml · kg−1 · min−1). When VT was expressed as a percentage of V̇O2 peak, there was no difference (p > .05) between tests. The RPE at VT, HR at VT, and VT expressed as a percentage of HRpeak were also similar (p > .05) between tests. Similar to V̇O2 peak, the V̇O2 at VT is dependent on the mode of exercise. However, when VT is expressed as a percentage of V̇O2 peak, it is independent of testing modality. The RPE at VT appears to be linked to a percentage of V̇O2 peak rather than an absolute V̇O2.

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Emma L. J. Eyre, Jason Tallis, Susie Wilson, Lee Wilde, Liam Akhurst, Rildo Wanderleys and Michael J. Duncan

ActiGraph monitors, suggesting it provides a valid and accurate estimate of physical activity intensities ( John, Tylo & Basset, 2010 ; Plasqui & Westerterp, 2007 ). A newer tool, the GENEActiv, has demonstrated excellent reliability and validity against breath-by-breath VO 2 , derived from indirect