This study tested the hypothesis that the DMAX (for maximal distance) method could be applied to ratings of perceived exertion (RPE), to propose a novel method for individual detection of the lactate threshold (LT) using RPE alone during an incremental test to exhaustion. Twenty-one participants performed an incremental test on a cycle ergometer. At the end of each stage, lactate concentration was measured and the participants estimated RPE using the Borg CR100 scale. The intensity corresponding to the fixed lactate values of 2 or 4 mmol · L−1(2mM and 4mM), the ventilatory threshold (VT), the respiratory-compensation point (RCP), and the instant of equality of pulmonary gas exchange (RER=1.00) were determined. Lactate (DMAX La) and RPE (DMAX RPE) thresholds were determined using the DMAX method. Oxygen uptake (VO2), heart rate, and power output measured at DMAX RPE and at DMAX La were not statistically different. Bland-Altman plots showed small bias and good agreements when DMAX RPE was compared with the DMAX La and RER=1.00 methods (bias = −0.05% and −2% of VO2max, respectively). Conversely, VO2 from the DMAX RPE method was lower than VO2 at 4 mM and at RCP and was higher than VO2 at 2 mM and at VT. VO2 at DMAX RPE was strongly correlated with VO2 at DMAX La (r = .97), at RER=1.00 (r = .97), at 2 mM (r = .85), at 4 mM (r = .93), at VT (r = .95), and at RCP (r = .95). The combination of the DMAX method with the RPE responses permitted precise and individualized estimates of LT using the DMAX method.
Nicolas Fabre, Laurent Mourot, Livio Zerbini, Barbara Pellegrini, Lorenzo Bortolan and Federico Schena
Vanessa Martínez-Lagunas and Ulrich Hartmann
To evaluate the validity of the Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) for the direct assessment and the indirect estimation of maximal oxygen consumption (VO2max) in female soccer players compared with a maximal laboratory treadmill test (LTT).
Eighteen female soccer players (21.5 ± 3.4 y, 165.6 ± 7.5 cm, 63.3 ± 7.4 kg; mean ± SD) completed an LTT and a YYIR1 in random order (1 wk apart). Their VO2max was directly measured via portable spirometry during both tests and indirectly estimated from a published non-gender-specific formula (YYIR1-F1).
The measured VO2max values in LTT and YYIR1 were 55.0 ± 5.3 and 49.9 ± 4.9 mL · kg−1 · min−1, respectively, while the estimated VO2max values from YYIR1-F1 corresponded to 45.2 ± 3.4 mL · kg−1 · min−1. Large positive correlations between the VO2max values from YYIR1 and LTT (r = .83, P < .001, 90% confidence interval = .64–.92) and YYIR1-F1 and LTT (r = .67, P = .002, .37–.84) were found. However, the YYIR1 significantly underestimated players’ VO2max by 9.4% compared with LTT (P < .001) with Bland-Altman 95% limits of agreement ranging from –20.0% to 1.4%. A significant underestimation from the YYIR1-F1 (P < .001) was also identified (17.8% with Bland-Altman 95% limits of agreement ranging from –31.8% to –3.8%).
The YYIR1 and YYIR1-F1 are not accurate methods for the direct assessment or indirect estimation of VO2max in female soccer players. The YYIR1-F1 lacks gender specificity, which might have been the reason for its larger error.
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).
Kenneth H. Pitetti, Bo Fernhall, Nancy Stubbs and Louis V. Stadler Jr.
The purpose of this study was to determine if a step test could be feasible, reliable, and valid for youths with educable (EMR) or trainable (TMR) mental retardation. Thirteen males and 11 females (age M = 14.7 ± 2.7 yr) with EMR or TMR participated in this study. Three step tests were employed using one platform height and stepping frequencies of 13, 15, and 17 ascents/min for 3 min. Recovery HR was used to estimate VO2peak. Though significant, correlations between the recovery HR and VO2peak for the 15 (r = −0.48) and 17 (r = −0.46) ascents/min were not high enough to be considered valid indicators of VO2peak. The large standard errors of the estimate and total errors suggested systematic errors of prediction. Furthermore, the measured VO2peak was significantly different from the estimated values at all step rates (p < .05). The step-test was relatively feasible, but was not a valid test of VO2peak in this population.
Ian G. Campbell, Clyde Williams and Henryk K.A. Lakomy
The purpose was to examine selected physiological responses of endurance-trained male wheelchair athletes in different Paralympic racing classes (T2, n = 3; T3, n = 8; T4, n = 7) during a 10-km treadmill time trial (TM:10-km). Peak oxygen uptake (V̇O2 peak) was determined, and a TM:10-km was completed on a motorized treadmill. From this, % V̇O2peak utilized and the relationship between V̇O2peak and TM:10-km were established. During the TM:10-km, the following dependent variables were examined: propulsion speed, oxygen uptake, respiratory exchange ratio, and heart rate. The results showed athletes utilize a high % V̇O2peak (78.4 –13.6%) during the TM:10-km. There was a moderate correlation (r = -.57, p < .01) between VO2peak and TM:10-km. No physiological differences were found between the paraplegic racing classes (T3, T4), which suggests that there is some justification in amalgamating these racing classes for endurance events.
Glen E. Duncan, Anthony D. Mahon, Cheryl A. Howe and Pedro Del Corral
This study examined the influence of test duration and anaerobic capacity on VO2max and the occurrence of a VO2 plateau during treadmill exercise in 25 boys (10.4 ± 0.8 years). Protocols with 1-min (P1) and 2-min (P2) stages, but identical speed and grade changes, were used to manipulate test duration. On separate days, VO2max was measured on P1 and P2, and 200-m run time was assessed. At maximal exercise, VO2, heart rate (HR), and pulmonary ventilation (VE) were similar between protocols, however, respiratory exchange ratio (RER) and treadmill elevation were higher (p < .05) on P1 than on P2. Plateau achievement was not significantly different. On P1, there were no differences between plateau achievers and nonachievers. On P2, test duration and 200-m run time were superior (p < .05), and relative VO2max tended to be higher (p < .10) in plateau achievers. Indices of aerobic and anaerobic capacity may influence plateau achievement on long, but not short duration tests.
Bo Fernhall and Garth T. Tymeson
This study evaluated the concurrent validity of the 300-yard and the 1.5-mile run with a group of mildly mentally retarded (MR) adults. The subjects, 15 healthy MR adults (M age = 29.5 + 5.6 yrs, M IQ = 60), underwent a maximal treadmill test utilizing a walking protocol, with heart rate and oxygen consumption data collected every minute. They also completed a 300-yard and a 1.5-mile run. The order of testing was counterbalanced. The results indicated that these subjects exhibited very poor cardiovascular fitness levels, with a mean V̇O2max of 28.1 ml•kg-1•min-1 and mean run times of 98.9 sec and 21.1 min for the 300-yard and the 1.5-mile runs, respectively. The correlation between V̇O2max and the 1.5-mile run was –.88, and the correlation for the 300-yard run and V̇O2max was –.71. However, partial correlations indicated that when the effect of height and weight were held constant, only the correlation between V̇O2max and the 1.5-mile run remained significant whereas that between V̇O2max and the 300-yard run dropped. Consequently, the 1.5-mile run appears to be a valid indicator of cardiovascular fitness for these adults with MR, but the 300 yard run is not.
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.
Joanne R. Williams and Neil Armstrong
This investigation set out to estimate exercise intensity and blood lactate corresponding to the maximal lactate steady state (MLaSS) and also examined the relationship between performance at the MLaSS with performance at fixed blood lactate reference values of 2.5 and 4.0 mmol•1−1. Cardiopulmonary responses at peak treadmill exercise and blood lactate reference values were measured in 10 boys and 8 girls ages 13-14 years. The 2.5 mmol•11 reference value represented 84±7% peak VO2 in boys and 82±6% peak VO2 in girls. Corresponding values at the 4.0 mmol•1−1 level were 93±6% and 90±5% peak VO2. MLaSS occurred at 77±7% peak VO2 in boys and 76±7% peak VO2 in girls. Blood lactate at the MLaSS was 2.1±0.5 mmol•l−1 in boys and 2.3±0.6 mmol•l−1 in girls. Cardiopulmonary and heart rate responses at the MLaSS were not significantly different from corresponding responses at the 2.5 mmol•l−1 reference value. In contrast, cardiopulmonary responses at the 4.0 mmol•l−1 reference level were significantly higher than those at the MLaSS. These data indicate that a 2.5 mmol•l−1 criterion for assessing aerobic performance in children may be the most appropriate.
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.