Peak oxygen consumption (VO 2 peak) reflects the capability of the cardiorespiratory system to transport oxygen during strenuous exercise ( 22 ) and is an objective measure of youth aerobic fitness ( 23 ). Cardiorespiratory fitness is an independent risk factor for cardiovascular disease, and
Stacy N. Scott, Cary M. Springer, Jennifer F. Oody, Michael S. McClanahan, Brittany D. Wiseman, Tyler J. Kybartas and Dawn P. Coe
Magnus Dencker, Bianca Hermansen, Anna Bugge, Karsten Froberg and Lars B. Andersen
This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers. Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4–7%. Further analyses showed the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3–6%.
Cameron P. Brewer, Brian Dawson, Karen E. Wallman and Kym J. Guelfi
Research into supplementation with sodium phosphate has not investigated the effects of a repeated supplementation phase. Therefore, this study examined the potential additive effects of repeated sodium phosphate (SP) supplementation on cycling time-trial performance and peak oxygen uptake (VO2peak). Trained male cyclists (N = 9, M ± SD VO2peak = 65.2 ± 4.8 ml · kg−1 · min−1) completed baseline 1,000-kJ time-trial and VO2peak tests separated by 48 hr, then ingested either 50 mg · kg fat-free mass−1 · d−1 of tribasic SP or a combined glucose and NaCl placebo for 6 d before performing these tests again. A 14-d washout period separated the end of one loading phase and the start of the next, with 2 SP and 1 placebo phase completed in a counterbalanced order. Although time-trial performance (55.3–56.5 min) was shorter in SP1 and SP2 (~60–70 s), effect sizes and smallest-worthwhile-change values did not differ in comparison with baseline and placebo. However, mean power output was greater than placebo during time-trial performance at the 250-kJ and 500-kJ time points (p < .05) after the second SP phase. Furthermore, mean VO2peak values (p < .01) were greater after the SP1 (3.5–4.3%), with further improvements (p < .01) found in SP2 (7.1–7.7%), compared with baseline and placebo. In summary, repeated SP supplementation, ingested either 15 or 35 d after initial loading, can have an additive effect on VO2peak and possibly time-trial performance.
Stamatis Agiovlasitis, Kenneth H. Pitetti, Myriam Guerra and Bo Fernhall
This study examined whether 20-m shuttle-run performance, sex, body mass index (BMI), age, height, and weight are associated with peak oxygen uptake (VO2peak) in youth with Down syndrome (DS; n = 53; 25 women, age 8–20 years) and whether these variables can be used to develop an equation to predict VO2peak. BMI, 20-m shuttle-run performance, and sex were significantly associated with VO2peak in youth with DS, whereas age, height, and weight were not. A regression model included only shuttle-run performance as a significant predictor of VO2peak; however, the developed prediction equation had low individual predictability. Therefore, 20-m shuttle-run performance alone does not provide valid prediction of VO2peak in youth with DS. Sex, BMI, age, height, and weight do not improve the prediction of VO2peak.
Mark Loftin, Patricia Strikmiller, Barbara Warren, Leann Myers, Leslie Schroth, James Pittman, David Harsha and Melinda Sothern
Peak cardiorespiratory responses, physical activity patterns, and the association of VO2peak and physical activity were examined in 16 elementary (ES) and 16 high school (HS) females. Peak responses were assessed during treadmill running, and physical activity patterns were examined over two 12-hour weekdays. Results indicated similar relative VO2peak responses between groups (ES: M = 46.8 ml · kg−1 · min−1;HS:M = 46.6 ml · kg−1 · min−1). No statistical differences (p ≤ .05) were noted when moderate to vigorous physical activity (MVPA) and vigorous physical activity (VPA) were compared. Also, a three-way (Group × HR level × Sustained minutes) ANOVA revealed no statistical differences. A median correlation (r = .27) was found from 8 independent correlations of habitual physical activity and VO2peak. ES and HS appeared similar in regard to VO2peak, accumulative and sustained MVPA and VPA. Low levels of sustained MVPA and VPA (≥ 10 min) were evident in both groups.
Matthew T. Mahar, Gregory J. Welk, David A. Rowe, Dana J. Crotts and Kerry L. McIver
The purpose of this study was to develop and cross-validate a regression model to estimate VO2peak from PACER performance in 12- to 14-year-old males and females.
A sample of 135 participants had VO2peak measured during a maximal treadmill test and completed the PACER 20-m shuttle run. The sample was randomly split into validation (n = 90) and cross-validation (n = 45) samples. The validation sample was used to develop the regression equation to estimate VO2peak from PACER laps, gender, and body mass.
The multiple correlation (R) was .66 and standard error of estimate (SEE) was 6.38 ml·kg−1·min−1. Accuracy of the model was confirmed on the cross-validation sample. The regression equation developed on the total sample was: VO2peak = 47.438 + (PACER*0.142) + (Gender[m=1, f=0]*5.134) − (body mass [kg]*0.197), R = .65, SEE = 6.38 ml·kg–1·min–1.
The model developed in this study was more accurate than the Leger et al. model and allows easy conversion of PACER laps to VO2peak.
Paul M. Vanderburgh
Previously there existed no efficacious maximal effort, VO2peak prediction test for subjects who, because of injury, can exercise at high intensity only on a device such as a cycle ergometer. This study's purpose was to develop and validate such a test, a 12-Minute Stationary Cycle Ergometer Test (12MSCET), for college-age physically active men and women. For 60 college-age men and women, and a gender-based resistance setting, the total work done on the 12MSCET and body weight were found to be highly predictive of VO2peak, measured via open circuit spirometry. Furthermore, the torques required for such a test are, for this sample, approximately 50% of those required in other predictive protocols. To date, the 12MSCET has been used for VO2peak assessment of over 300 military cadets who, because of injury, found cycling their only efficacious high-intensity aerobic modality.
Kenneth H. Pitetti, Bo Fernhall and Steve Figoni
Two regression equations were developed to predict cardiovascular fitness (CVF) based on the 20-m shuttle run test (20-MST) for nondisabled youth and for youth with mild mental retardation (MR). The purpose of this study was to compare the validity of both regression formulas to predict CVF in nondisabled, healthy youths (ages 8 to 15 yrs; 38 females and 13 males). Participants performed two modified Bruce protocol treadmill (TM) tests and two 20-MSTs on separate days. CVF (V̇O2peak, ml • kg−1 • min−1) was measured during the TM tests and computed for the 20-MST using both regression equations. Results indicate that test-retest correlations for the 20-MST (# of laps; r = 0.89) and TM test (V̇O2peak, ml • kg−1 • min−1; r = 0.86) were high. Predicted V̇O2peak values were moderately significant (nondisabled youth: r = 0.55, p < .01; youth with MR: r = 0.66, p < .01) when compared with TM V̇O2peak. Correlation between the two regression equations was significant (r = 0.78, p < .01).
Beverly J. Warren, Ruth G. Dotson, David C. Nieman and Diane E. Butterworth
The accuracy of a 1-mile walking test to estimate aerobic power was assessed in a group of 28 sedentary elderly women (age = 73.5 ±0.8 yrs; body mass = 66.0 ±2.2 kg). Subjects were given the walk test and a graded maximal treadmill test for VO2peak at baseline and then were randomly assigned to either a walking group or a mild calisthenics control group for 12 weeks. Both the treadmill test and the walk test were re-administered at 5 weeks and at 12 weeks. The data suggest that regression approaches underestimate measured VO2peak by 17% in sedentary elderly women, but that accuracy is much improved after 5 weeks of brisk walking. Measurements at 12 weeks demonstrated even closer approximations of the laboratory measurement of VO2peak for the walking group. The 1-mile walk test underestimated VO2peak for the calisthenics group by 11% at the end of the 12 weeks. It was concluded that the 1-mile walk test underestimates measured VO2peak in elderly women unless they are accustomed to brisk walking.
Christine L. LaLanne, Michael S. Cannady, Joseph F. Moon, Danica L. Taylor, Jeff A. Nessler, George H. Crocker and Sean C. Newcomer
Participation in surfing has evolved to include all age groups. Therefore, the purpose of this study was to determine whether activity levels and cardiovascular responses to surfing change with age. Surfing time and heart rate (HR) were measured for the total surfing session and within each activity of surfing (paddling, sitting, wave riding, and miscellaneous). Peak oxygen consumption (VO2peak) was also measured during laboratory-based simulated surfboard paddling on a modified swim bench ergometer. VO2peak decreased with age during simulated paddling (r = –.455, p < .001, n = 68). Total time surfing (p = .837) and time spent within each activity of surfing did not differ with age (n = 160). Mean HR during surfing significantly decreased with age (r = –.231, p = .004). However, surfing HR expressed as a percent of age-predicted maximum increased significantly with age. Therefore, recreational surfers across the age spectrum are achieving intensities and durations that are consistent with guidelines for cardiovascular health.