We cross validated the 20-m shuttle run test of aerobic capacity in children and adolescents with mild and moderate mental retardation (MR) using the population specific formula of Fernhall et al. (1998). Nine boys and 8 girls (age = 13.7 yr) completed a maximal treadmill protocol (measured V̇O2peak) and a 20-m shuttle run (predicted V̇O2peak). The measured peak oxygen consumption (V̇O2peak) was 39.4 ml kg-1 min-1. The relationship between measured and predicted V̇O2peak was r = .86 with an SEE of 6.2 ml kg-1 min-1. Multiple regression and Bland-Altman analyses showed that there was little bias, but the Bland-Altman analysis indicated highly variable limits of agreement (Bland & Altman 1986). Thus, the traditional approach (regression analysis) to concurrent validity revealed that the 20-m shuttle run is a valid indicator of V̇O2peak in these participants. The accuracy of prediction (Bland & Altman, 1986), however, was lower than expected in a population without MR.
Bo Fernhall, A. Lynn Millar, Kenneth H. Pitetti, Terri Hensen and Mathew D. Vukovsch
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.
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.
George T. Hardison Jr., Richard G. Israel and Grant W. Somes
The purpose of this study was to identify the most desirable cranking rate to be used by paraplegic individuals during submaximal arm training programs. Eleven healthy paraplegic males (M age = 28.8 years) with lesion levels ranging from T4 to T12 served as subjects. Arm exercise loads for the four submaximal cranking rates studied (50, 60, 70, and 80 rpm) were set to elicit 60% of peak V̇O2. Duration of the submaximal tests was 15 min. V̇E, V̇O2, RER, HR, and differentiated RPE were recorded each minute throughout the 15-min test. A randomized block ANOVA and Duncan’s post hoc analysis indicated that 80 rpm produced significantly higher (p <.05) values for HR, absolute V̇O2, V̇E, V̇CO2, and V̇E/V̇O2 than any other rates. Cranking at 70 rpm resulted in significantly higher (p <.05) values for O2 pulse, while relative V̇O2 was significantly higher (p <05) at 70 rpm than at all other rates except 80 rpm. RPE was significantly higher (p <.05) at 50 rpm than at 60 or 70 rpm, with no difference between 50 and 80 or 60, 70, and 80. The authors concluded that 70 rpm was the most appropriate cranking rate for paraplegic males to use during arm training programs.
Ana Sousa, Pedro Figueiredo, David Pendergast, Per-Ludvik Kjendlie, João P. Vilas-Boas and Ricardo J. Fernandes
Swimming has become an important area of sport science research since the 1970s, with the bioenergetic factors assuming a fundamental performance-influencing role. The purpose of this study was to conduct a critical evaluation of the literature concerning oxygen-uptake (VO2) assessment in swimming, by describing the equipment and methods used and emphasizing the recent works conducted in ecological conditions. Particularly in swimming, due to the inherent technical constraints imposed by swimming in a water environment, assessment of VO2max was not accomplished until the 1960s. Later, the development of automated portable measurement devices allowed VO2max to be assessed more easily, even in ecological swimming conditions, but few studies have been conducted in swimming-pool conditions with portable breath-by-breath telemetric systems. An inverse relationship exists between the velocity corresponding to VO2max and the time a swimmer can sustain it at this velocity. The energy cost of swimming varies according to its association with velocity variability. As, in the end, the supply of oxygen (whose limitation may be due to central—O2 delivery and transportation to the working muscles—or peripheral factors—O2 diffusion and utilization in the muscles) is one of the critical factors that determine swimming performance, VO2 kinetics and its maximal values are critical in understanding swimmers’ behavior in competition and to develop efficient training programs.
Myriam Guerra, Kenneth H. Pitetti and Bo Fernhall
The purpose of this study was to determine if the regression formula developed for the 20-m shuttle run test (20 MST) for children and adolescents with mild mental retardation (MR), used to predict cardiovascular fitness (V̇O2peak), is valid for adolescents with Down syndrome (DS). Twenty-six adolescents (mean age = 15.3 ± 2.7 yr) with DS (15 males, 11 females) completed a maximal treadmill protocol (measured V̇O2peak) and a 20 MST (predicted V̇O2peak). There was a significant difference (p < .01) between the means of the measured (25.5 ± 5.2 ml·kg-1-·min-1) and the predicted (33.5 ± 3.9 ml·kg-1·min-1) V̇O2peak, respectively. In addition, there was a low relationship between measured and predicted values (r = .54). The results of this study indicate that the regression formula developed for children and adolescents with MR to predict V̇O2peak was not valid in this sample of adolescents with DS.
Monique Mendelson, Anne-Sophie Michallet, Julia Tonini, Anne Favre-Juvin, Michel Guinot, Bernard Wuyam and Patrice Flore
To examine the role of ventilatory constraint on cardiorespiratory fitness in obese adolescents.
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.
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.
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.
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.
Renee E. Magnan, Bethany M. Kwan, Joseph T. Ciccolo, Burke Gurney, Christine M. Mermier and Angela D. Bryan
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.
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.
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.
Findings raise questions about the validity of commonly used criteria with less active populations.
Amanda J. Visek, Erin A. Olson and Loretta DiPietro
Little is known about factors affecting adherence to highly-structured and supervised exercise programs in older people.
Healthy, inactive older (≥65 y) women (N = 30) were randomized into a 1) higher- (ATH—80% VO2peak); 2) moderate- (ATM—65% VO2peak) intensity aerobic; or 3) lower-intensity resistance (RTL; 50% VO2peak) group. All 3 groups exercised 4 days·week-1 for an average of 45 to 70 min·session-1 over 9 months. Adherence (%) was defined as the proportion of prescribed sessions (N = 144) in which subjects achieved their 1) prescribed heart rate (intensity adherence) and 2) their prescribed duration (duration adherence). Primary determinants of adherence included prescribed intensity (METs) and prescribed duration (min), as well as age, body composition, VO2peak, and exercise self-efficacy score.
Intensity adherence was nearly 100% for all 3 groups, while duration adherence was 95%, 91%, and 85% in the RTL, ATH, and ATM groups, respectively. Prescribed exercise duration was the strongest determinant of duration adherence (r = −0.72; P < .0001), independent of prescribed METs, age, VO2peak, and body composition.
Due to competing lifestyle demands, exercise intensity may be less of a factor in adherence among older women than is exercise duration.