Relationships among chronological age (CA), maturation, training experience, and body dimensions with peak oxygen uptake (VO2max) were considered in male basketball players 14–16 y of age. Data for all players included maturity status estimated as percentage of predicted adult height attained at the time of the study (Khamis-Roche protocol), years of training, body dimensions, and VO2max (incremental maximal test on a treadmill). Proportional allometric models derived from stepwise regressions were used to incorporate either CA or maturity status and to incorporate years of formal training in basketball. Estimates for size exponents (95% CI) from the separate allometric models for VO2max were height 2.16 (1.23–3.09), body mass 0.65 (0.37–0.93), and fat-free mass 0.73 (0.46–1.02). Body dimensions explained 39% to 44% of variance. The independent variables in the proportional allometric models explained 47% to 60% of variance in VO2max. Estimated maturity status (11–16% of explained variance) and training experience (7–11% of explained variance) were significant predictors with either body mass or estimated fat-free mass (P ≤ .01) but not with height. Biological maturity status and training experience in basketball had a significant contribution to VO2max via body mass and fat-free fat mass and also had an independent positive relation with aerobic performance. The results highlight the importance of considering variation associated with biological maturation in aerobic performance of late-adolescent boys.
Humberto M. Carvalho, Manuel J. Coelho-e-Silva, Joey C. Eisenmann and Robert M. Malina
John M. Schuna Jr., Tiago V. Barreira, Daniel S. Hsia, William D. Johnson and Catrine Tudor-Locke
Energy expenditure (EE) estimates for a broad age range of youth performing a variety of activities are needed.
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.
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.
Descriptive EE data presented herein will augment the Youth Compendium of Physical Activities.
Thomas Losnegard, Martin Andersen, Matt Spencer and Jostein Hallén
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.
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.
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.
Neither passive recovery nor running at ~58% of VO2peak between 2 heats changed performance significantly.
Saul R. Bloxham, Joanne R. Welsman and Neil Armstrong
This study examined ergometer-specific relationships between short-term power and peak oxygen uptake (peak VO2) in children. Boys (n = 28) and girls (n = 28) age 11-12 years completed two incremental tests to exhaustion on a cycle ergometer and motorized treadmill for the determination of peak VO2. In addition, they completed two 30 s “all-out” sprint tests, one on a cycle ergometer and one on a nonmotorized treadmill for the assessment of peak power (PP) and mean power (MP). Relationships between peak VO2 and shortterm power measures were examined by sex for cycle- and treadmill-derived data using simple per-body-mass ratios and sample-specific allometric exponents to control for body size differences. From correlational analyses on scaled data, sex differences in responses were shown. In boys, PP and MP were unrelated to peak VO2 for cycle-derived measures but significantly related (r = 0.58 PP; r = 0.69 MP) for treadmill values. PP and MP were significantly related to peak VO2 for both modes of exercise in girls (r = .41−.68). In all but one case, correlation coefficients based on mass-related data were higher than those based on allometrically adjusted data.
Danette M. Rogers, Kenneth R. Turley, Kathleen I. Kujawa, Kevin M. Harper and Jack H. Wilmore
This study was designed to examine the relationship between oxygen consumption and both body surface area and body mass in children to determine what allometric scaling factors from these variables provide appropriate means of expressing data for this population. These scaling factors were then compared to exponents based on theoretical and animal models to determine if the same relationships were present. Forty-two children (21 boys and 21 girls) 7 to 9 years of age participated in maximal and submaximal treadmill testing. The submaximal V̇O2 to body size relationship proved to be a more appropriate factor to use when scaling V̇O2 than the relationship seen between body size and V̇O2max. Therefore, in this population of children, V̇O2 relative to body surface area or body mass to the power 0.67, demonstrated submaximally, provided a more appropriate means of data expression both statistically and physiologically than the traditional expression of V̇O2 relative to body mass (ml·kg−1·min−1).
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
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.
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.
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.
Jerry Mayo, Brian Lyons, Kendal Honea, John Alvarez and Richard Byrum
Rehabilitation specialists should understand cardiovascular responses to different movement patterns.
To investigate physiological responses to forward- (FM), backward- (BM), and lateral-motion (LM) exercise at self-selected intensities.
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).
10 healthy women.
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.
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