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John M. Schuna Jr., Tiago V. Barreira, Daniel S. Hsia, William D. Johnson and Catrine Tudor-Locke

Background:

Energy expenditure (EE) estimates for a broad age range of youth performing a variety of activities are needed.

Methods:

106 participants (6–18 years) completed 6 free-living activities (seated rest, movie watching, coloring, stair climbing, basketball dribbling, jumping jacks) and up to 9 treadmill walking bouts (13.4 to 120.7 m/min; 13.4 m/min increments). Breath-by-breath oxygen uptake (VO2) was measured using the COSMED K4b2 and EE was quantified as youth metabolic equivalents (METy1:VO2/measured resting VO2, METy2:VO2/estimated resting VO2). Age trends were evaluated with ANOVA.

Results:

Seated movie watching produced the lowest mean METy1 (6- to 9-year-olds: 0.94 ± 0.13) and METy2 values (13- to 15-year-olds: 1.10 ± 0.19), and jumping jacks produced the highest mean METy1 (13- to 15-year-olds: 6.89 ± 1.47) and METy2 values (16- to 18-year-olds: 8.61 ± 2.03). Significant age-related variability in METy1 and METy2 were noted for 8 and 2 of the 15 evaluated activities, respectively.

Conclusions:

Descriptive EE data presented herein will augment the Youth Compendium of Physical Activities.

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Renee E. Magnan, Bethany M. Kwan, Joseph T. Ciccolo, Burke Gurney, Christine M. Mermier and Angela D. Bryan

Background:

Maximal oxygen uptake (VO2max), an assessment of cardiorespiratory fitness, is regularly used as the primary outcome in exercise interventions. Many criteria have been suggested for validating such tests—most commonly, a plateau in oxygen consumption. The current study investigated the proportion of inactive individuals who reached a plateau in oxygen uptake and who achieved a valid test as assessed by secondary criteria (RERmax ≥ 1.1; RPEmax ≥ 18; age predicted HRmax ±10bpm), and the correlates of a successful plateau or achievement of secondary criteria during a VO2max session.

Methods:

Participants (n = 240) were inactive individuals who completed VO2max assessments using an incremental treadmill test. We explored physical, behavioral, and motivational factors as predictors of meeting criteria for meeting a valid test.

Results:

Approximately 59% of the sample achieved plateau using absolute (increase of VO2 of 150ml O2 or less) and 37% achieved plateau using relative (increase of VO2 of 1.5ml/kg O2 or less) criteria. Being male, having a higher BMI, a greater waist-to-hip ratio, and increased self-efficacy were associated with lower odds of achieving an absolute plateau, whereas none of these factors predicted odds of achieving relative plateau.

Conclusion:

Findings raise questions about the validity of commonly used criteria with less active populations.

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Ralph K.L. Rogers, Tony Reybrouck, Maria Weymans, Monique Dumoulin, Marc Gewillig and Paul Vaccaro

This study assessed the relationship between the VO2 measured at ventilatory threshold (VT) and the VO2 measured at the point of deflection from linearity of heart rate (HRD). Twelve children (10 boys and 2 girls) with a mean age of 11.3 years (±4.8) performed a graded exercise test to determine VT and HRD. All children had undergone surgical repair for d-transposition of the great arteries at approximately 13 months of age. Because of failure to demonstrate HRD, the data from 4 patients were excluded from statistical analysis. For the remaining 8 patients there was no significant difference between mean VO2 (ml/kg/min) at VT and HRD (26.6 ± 6.4 vs. 26.3 ± 6.8; p > 0.25). Linear regression analysis revealed a correlation of r = 0.92 between the VO2 measured at VT and the VO2 measured at HRD. Only 8 of the 12 patients (66%) in this study satisfied criteria needed to identify the HRD. Therefore HRD may be an accurate predictor of VT in most but not all children who have had surgery for d-transposition of the great arteries.

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Monique Mendelson, Anne-Sophie Michallet, Julia Tonini, Anne Favre-Juvin, Michel Guinot, Bernard Wuyam and Patrice Flore

Aim:

To examine the role of ventilatory constraint on cardiorespiratory fitness in obese adolescents.

Methods:

Thirty obese adolescents performed a maximal incremental cycling exercise and were divided into 2 groups based on maximal oxygen uptake (VO2peak): those presenting low (L; n = 15; VO2peak: 72.9 ± 8.6% predicted) or normal (N; n = 15; VO2peak: 113.6 ± 19.2% predicted) cardiorespiratory fitness. Both were compared with a group of healthy controls (C; n = 20; VO2peak: 103.1 ± 11.2% predicted). Ventilatory responses were explored using the flow volume loop method.

Results:

Cardiorespiratory fitness (VO2peak, in % predicted) was lower in L compared with C and N and was moderately associated with the percent predicted forced vital capacity (FVC) (r = .52; p < .05) in L. At peak exercise, end inspiratory point was lower in L compared with N and C (77.4 ± 8.1, 86.4 ± 7.7, and 89.9 ± 7.6% FVC in L, N, and C, respectively; p < .05), suggesting an increased risk of ventilatory constraint in L, although at peak exercise this difference could be attributed to the lower maximal ventilation in L.

Conclusion:

Forced vital capacity and ventilatory strategy to incremental exercise slightly differed between N and L. These results suggest a modest participation of ventilatory factors to exercise intolerance.

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Thomas Losnegard, Martin Andersen, Matt Spencer and Jostein Hallén

Purpose:

To investigate the effects of an active and a passive recovery protocol on physiological responses and performance between 2 heats in sprint cross-country skiing.

Methods:

Ten elite male skiers (22 ± 3 y, 184 ± 4 cm, 79 ± 7 kg) undertook 2 experimental test sessions that both consisted of 2 heats with 25 min between start of the first and second heats. The heats were conducted as an 800-m time trial (6°, >3.5 m/s, ~205 s) and included measurements of oxygen uptake (VO2) and accumulated oxygen deficit. The active recovery trial involved 2 min standing/walking, 16 min jogging (58% ± 5% of VO2peak), and 3 min standing/walking. The passive recovery trial involved 15 min sitting, 3 min walk/jog (~ 30% of VO2peak), and 3 min standing/walking. Blood lactate concentration and heart rate were monitored throughout the recovery periods.

Results:

The increased 800-m time between heat 1 and heat 2 was trivial after active recovery (effect size [ES] = 0.1, P = .64) and small after passive recovery (ES = 0.4, P = .14). The 1.2% ± 2.1% (mean ± 90% CL) difference between protocols was not significant (ES = 0.3, P = .3). In heat 2, peak and average VO2 was increased after the active recovery protocol.

Conclusions:

Neither passive recovery nor running at ~58% of VO2peak between 2 heats changed performance significantly.

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Courteney L. Benjamin, William M. Adams, Ryan M. Curtis, Yasuki Sekiguchi, Gabrielle E.W. Giersch and Douglas J. Casa

[ M ] age = 19 years, standard deviation [ SD ] age = 1 year; M [ SD ] body mass = 58.8 [9.6] kg; M [ SD ] height = 168.4 [7.7] cm; M [ SD ] VO 2max  = 53.6 [5.6] mL·kg −1 ·min −1 ) participated in this study, which took place during the 2016 NCAA cross-country season (August–December) in the

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Eric D. Vidoni, Anna Mattlage, Jonathan Mahnken, Jeffrey M. Burns, Joe McDonough and Sandra A. Billinger

The purpose of this study was to determine the validity of a submaximal exercise test, the Step Test Exercise Prescription (STEP), in a broad age range and in individuals in the earliest stages of Alzheimer’s disease (AD). Individuals (n = 102) underwent treadmill-based maximal exercise testing and a STEP. The STEP failed to predict peak oxygen consumption (VO2peak), and was a biased estimate of VO2peak (p < .0001). Only 43% of subjects’ STEP results were within 3.5 ml · kg–1 · min–1 of VO2peak. When categorized into fitness levels these 2 measures demonstrated moderate agreement (kappa = .59). The validity of the STEP was not supported in our participants, including those with AD. The STEP may not be appropriate in the clinic as a basis for exercise recommendations in these groups, although it may continue to have utility in classifying fitness in research or community health screenings.

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Lee N. Burkett, Jack Chisum, Jack Pierce and Kent Pomeroy

Twenty spinal injured wheelchair bound individuals were tested to peak VO2 on a wheelchair ergometer. Sixteen subjects were paraplegics (5 females, 11 males) and four were quadriplegic (2 females, 2 males). The level of injury ranged from C4-5 to L2-3. The mean age of the subjects was 29.9 years, with a mean weight of 63.66 kg. Prior to the peak VO2 and during the rest immediately after peak VO2, each subject was tested for the ability to discriminate touch over the skin of the thigh, leg, and foot. A chi square statistical technique was used to test for differences between pre- and postexercise sensitivity. The chi square was significant at the .003 level of significance. Because the increase in sensitivity was short, it was theorized that under peak exercise stress the body may recruit pathways that have been dormant, but not injured, explaining the increase in sensitivity.

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Kenneth H. Pitetti, A. Lynn Millar and Bo Fernhall

The purpose of this study was to compare test-retest reliability when measuring peak physiological capacities of children and adolescents (age = 13.6 ± 2.9 yr) with mental retardation (MR) and their peers (12.0 ± 2.9 yr) without mental retardation (NMR) using a discontinuous treadmill (TM) protocol. Forty-six participants (23 MR = 12 male and 11 female; 23 NMR = 12 male and 11 female) completed two peak performance treadmill tests with 3 to 7 days of rest between tests. Physiological values measured included V̇O2peak (1 $$ min-1 and ml $$ kg-1 $$ min-1), V̇Epeak (1 $$ mhr-1), HRpeak (bpm), and RER (V̇O2 $$ V̇O2 -1). Test-retest reliability coefficients ranged from .85 to .99 for participants with MR and from .55 to .99 for participants without MR. Test reliability and accuracy in the present study does not appear to differ between the NMR and MR participants.

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Jerry Mayo, Brian Lyons, Kendal Honea, John Alvarez and Richard Byrum

Context:

Rehabilitation specialists should understand cardiovascular responses to different movement patterns.

Objective:

To investigate physiological responses to forward- (FM), backward- (BM), and lateral-motion (LM) exercise at self-selected intensities.

Design:

Within-subjects design to test independent variable, movement pattern; repeated-measures ANOVA to analyze oxygen consumption (VO2), heart rate (HR), respiratory-exchange ratio (RER), and ratings of perceived exertion (RPE).

Participants:

10 healthy women.

Results:

VO2 and HR were significantly higher during LM than during FM and BM exercise. The respective VO2 (ml · kg · min–1) and HR (beats/min) values for each condition were FM 25.19 ± 3.6, 142 ± 11; BM 24.24 ± 2.7, 145 ± 12; and LM 30.5 ± 4.6, 160 ± 13. No differences were observed for RER or RPE.

Conclusions:

At self-selected intensities all 3 modes met criteria for maintaining cardiovascular fitness. Practitioners can use these results to develop rehabilitation programs based on clients’ perception and level of discomfort