Search Results

You are looking at 31 - 40 of 1,124 items for :

Clear All
Restricted access

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.

Restricted access

Melitta A. McNarry

: 22433260 doi:10.1123/pes.24.1.2 22433260 10.1123/pes.24.1.2 6. Fawkner S , Armstrong N. Modelling the VO 2 kinetic response to moderate intensity exercise in children . Sports Med . 2002 ; 33 ( 9 ): 651 – 69 . doi:10.2165/00007256-200333090-00002 10.2165/00007256-200333090-00002 7. Jansson E

Restricted access

Matthew T. Mahar, Gregory J. Welk, David A. Rowe, Dana J. Crotts and Kerry L. McIver

Background:

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.

Methods:

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.

Results:

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.

Conclusions:

The model developed in this study was more accurate than the Leger et al. model and allows easy conversion of PACER laps to VO2peak.

Restricted access

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.

Restricted access

David R. Lubans, Philip J. Morgan, Robin Callister and Clare E. Collins

The purpose of this study was to examine the relationship between pedometer step counts and estimated VO2max as determined by a submaximal exercise test. Participants (N = 115; 65 girls, 50 boys) wore pedometers for five days and completed the Queen’s College Step Test (QCST). Based on these results participants were classified as HIGH, MOD, or LOW cardiorespiratory fitness. Boys accumulated more steps per day (p < .05) than girls (12,766 ± 4,923 versus 10,887 ± 2,656). The relationship between estimated VO2max and mean steps/day was moderate (r = .34, p < .01). Participants classified as having HIGH fitness levels accumulated more steps/day than LOW-fit adolescents (p < .05). The results from this study suggest that estimated VO2max as determined by a submaximal exercise test is moderately associated with mean steps/day in adolescents.

Restricted access

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).

Restricted access

Andrew Thomas, Brian Dawson and Carmel Goodman

Purpose:

The purpose of the study was to determine the reliability of yo-yo intermittent recovery test (yo-yo) scores and their degree of association with a 20-m shuttle run (20MSR) and VO2max values.

Methods:

Subjects were elite (Australian Football League [AFL], n = 23), state-level (hockey, n = 15, and cricket, n = 27), and recreational team-sport players (n = 33). All performed a 20MSR and the yo-yo at either level 1 (recreational and state level) or level 2 (AFL). A recreational subgroup (n = 19) also performed a treadmill VO2max test.

Results:

Test–retest results found the yo-yo (levels 1 and 2) to be reliable (ICC = .86 to .95). The 20MSR and yo-yo level 1 scores correlated (P < .01) in the recreational (r = .81 to .83) and state-level groups (r = .84 to .86), and 20MSR and yo-yo level 2 scores, in the elite (r = .86) and recreational groups (r = .55 to .57). The VO2max and yo-yo level 1 scores in the recreational group correlated (P < .01, r = .87), but no association was found with yo-yo level 2 (r = .40 to .43, non significant).

Conclusions:

We conclude that level 1 (recreational and state level) and level 2 (elite) yo-yo scores were both strongly associated with 20MSR scores and VO2max (level 1: recreational subjects only). The yo-yo appears to measure aerobic fitness similarly to the 20MSR but may also be used as a field test of the ability to repeat high-intensity efforts.

Restricted access

Jean M. Nyakayiru, Kristin L. Jonvik, Philippe J.M. Pinckaers, Joan Senden, Luc J.C. van Loon and Lex B. Verdijk

While the majority of studies reporting ergogenic effects of dietary nitrate have used a multiday supplementation protocol, some studies suggest that a single dose of dietary nitrate before exercise can also improve subsequent performance. We aimed to compare the impact of acute and 6-day sodium nitrate supplementation on oxygen uptake (V̇O2) and time-trial performance in trained cyclists. Using a randomized, double-blind, cross-over design, 17 male cyclists (25 ± 4 y, V̇O2peak 65 ± 4 ml·kg-1·min-1, Wmax 411 ± 35 W) were subjected to 3 different trials; 5 days placebo and 1 day sodium nitrate supplementation (1-DAY); 6 days sodium nitrate supplementation (6-DAY); 6 days placebo supplementation (PLA). Nitrate was administered as 1097 mg sodium nitrate providing 800 mg (~12.9 mmol) nitrate per day. Three hours after ingestion of the last supplemental bolus, indirect calorimetry was performed while subjects performed 30 min of exercise at 45% Wmax and 30 min at 65% Wmax on a cycle ergometer, followed by a 10 km time-trial. Immediately before exercise, plasma [nitrate] and [nitrite] increased to a similar extent during the 6-DAY and 1-DAY trial, but not with PLA (plasma nitrite: 501 ± 205, 553 ± 278, and 239 ± 74 nM, respectively; p < .001). No differences were observed between interventions in V̇O2 during submaximal exercise, or in time to complete the time-trial (6-DAY: 1004 ± 61, 1-DAY: 1022 ± 72, PLA: 1017 ± 71 s; p = .28). We conclude that both acute and 6-days of sodium nitrate supplementation do not alter V̇O2 during submaximal exercise or improve time-trial performance in highly trained cyclists, despite increasing plasma [nitrate] and [nitrite].

Restricted access

Brian R. Hunt, James D. George, Pat R. Vehrs, A. Garth Fisher and Gilbert W. Fellingham

The purpose of this study was to validate the ability of the 1-mile jog test to predict VO2max in fit teenagers. Forty-one males and 42 females performed the steady-state, submaximal jogging test on an indoor track, along with a maximal graded exercise test (GXT) on a treadmill. Open circuit calorimetry was used during the GXT to measure maximal oxygen consumption (VO2max). We generated the following age-specific prediction equation applicable to boys and girls 13–17 years old (n = 83, Radj = .88, SEE = 3.26 ml · kg−1 · min−1): VO2max = 92.91 + 6.50 × gender (0 = female, 1 = male) − 0.141 × body mass (kg) − 1.562 × jog time (min) − 0.125 × heart rate (bpm). Cross-validation results were acceptable (SEEpress = 3.44 ml · kg−1 · min−1). As a field test, the submaximal 1-mile jogging test may alleviate problems associated with pacing, motivation, discouragement, injury, and fatigue that are sometimes associated with maximal effort timed or distance run tests.

Restricted access

Barry Braun, Priscilla M. Clarkson, Patty S. Freedson and Randall L. Kohl

The effects of dietary supplementation with Coenzyme Q10 (CoQlO), a reputed performance enhancer and antioxidant, on physiological and biochemical parameters were examined. Ten male bicycle racers performed graded cycle ergometry both before and after being given 100 mg per day CoQlO or placebo for 8 weeks. Analysis of variance showed a significant difference between groups for postsupplementation serum CoQ10. Although both groups demonstrated training related improvements in all physiological parameters over the course of the study, there were no significant differences between the two groups (p>.05). Both groups showed a 21 % increase in serum MDA (an index of lipid peroxidation) after the presupplementation exercise test. After 8 weeks this increase was only 5 % , and again was identical for both groups. Supplementation with CoQlO has no measurable effect on cycling performance, VO2max, submaximal physiological parameters, or lipid peroxidation. However, chronic intense training seems to result in marked attenuation of exercise-induced lipid peroxidation.