The objective of this study was to verify the effect of the exercise mode on slow component of VO2 (VO2SC) in children aged 11–12 years during severe-intensity exercise. After determination of the lactate threshold (LT) and peak VO2 (VO2peak) in both cycling (CE) and running exercise (TR), fourteen active boys completed a series of “square-wave” transitions of 6-min duration at 75%∆ [75%∆ = LT + 0.75 × (VO2peak—LT)] to determine the VO2 kinetics. The VO2SC was significantly higher in CE (180.5 ± 155.8 ml • min−1) than in TR (113.0 ± 84.2 ml · min−1). We can conclude that, although a VO2SC does indeed develop during TR in children, its magnitude is considerably lower than in CE during severe-intensity exercise.
Fabiana A. Machado, >Luiz G. A. Guglielmo, Camila C. Greco and Benedito S. Denadai
Andreas Schuchert and Thomas Meinertz
It is more feasible to assess functional capacity with an exercise test than to measure peak-exercise VO2.
To assess whether maximal workload reliably predicts peak VO2.
Thirty-six patients after aortic-valve replacement during routine follow-up.
Incremental symptom-limited cycle exercise test in the upright position with increments of 20 W/min.
Out-clinic patients, university hospital.
Main Outcome Measures:
Maximal workload, ventilatory threshold, and peak VO2.
Maximal workload was 151 ± 39 W, and peak VO2, 1649 ± 486 ml/min. The correlation coefficient between maximal workload and peak VO2 was r = .92 (P < .0001). The regression equation for the estimation of peak VO2 was y = 11.7 (maximal workload in watts) – 110.7. Peak VO2 calculated with this equation was 1657 ± 451 ml/min.
Maximal workload during ergometry in the upright position reliably predicted peak VO2.
Nicholas J. Hanson, Sarah C. Martinez, Erik N. Byl, Rachel M. Maceri and Michael G. Miller
least 48 hours between testing sessions. The first visit included a VO 2 max test and familiarization with the laboratory equipment. During the first visit, the participants were also familiarized with the protocol and the rating of perceived exertion (RPE) scale. The second, third, and fourth visits
Diego Chaverri, Thorsten Schuller, Xavier Iglesias, Uwe Hoffmann and Ferran A. Rodríguez
Assessing cardiopulmonary function during swimming is a complex and cumbersome procedure. Backward extrapolation is often used to predict peak oxygen uptake (V̇O2peak) during unimpeded swimming, but error can derive from a delay at the onset of V̇O2 recovery. The authors assessed the validity of a mathematical model based on heart rate (HR) and postexercise V̇O2 kinetics for the estimation of V̇O2peak during exercise.
34 elite swimmers performed a maximal front-crawl 200-m swim. V̇O2 was measured breath by breath and HR from beat-to-beat intervals. Data were time-aligned and 1-s-interpolated. Exercise V̇O2peak was the average of the last 20 s of exercise. Postexercise V̇O2 was the first 20-s average during the immediate recovery. Predicted V̇O2 values (pV̇O2) were computed using the equation: pV̇O2(t) = V̇O2(t) HRend-exercise/HR(t). Average values were calculated for different time intervals and compared with measured exercise V̇O2peak.
Postexercise V̇O2 (0–20 s) underestimated V̇O2peak by 3.3% (95% CI = 9.8% underestimation to 3.2% overestimation, mean difference = –116 mL/min, SEE = 4.2%, P = .001). The best V̇O2peak estimates were offered by pV̇O2peak from 0 to 20 s (r 2 = .96, mean difference = 17 mL/min, SEE = 3.8%).
The high correlation (r 2 = .86–.96) and agreement between exercise and predicted V̇O2 support the validity of the model, which provides accurate V̇O2peak estimations after a single maximal swim while avoiding the error of backward extrapolation and allowing the subject to swim completely unimpeded.
Ashleigh E. Smith, Roger G. Eston, Belinda Norton and Gaynor Parfitt
Peak oxygen uptake (V̇O2peak) is reliably predicted in young and middle-aged adults using a submaximal perceptually-regulated exercise test (PRET). It is unknown whether older adults can use a PRET to accurately predict V̇O2peak. In this study, the validity of a treadmill-based PRET to predict V̇O2peak was assessed in 24 participants (65.2 ± 3.9 years, 11 males). The PRET required a change in speed or incline corresponding to ratings of perceived exertion (RPE) 9, 11, 13, and 15. Extrapolation of submaximal V̇O2 from the PRET to RPE endpoints 19 and 20 and age-predicted HRmax were compared with measured V̇O2peak. The V̇O2 extrapolated to both RPE19 and 20 over-predicted V̇O2peak (p < .001). However, extrapolating V̇O2 to age-predicted HRmax accurately predicted V̇O2peak (r = .84). Results indicate older adults can use a PRET to predict V̇O2peak by extrapolating V̇O2 from submaximal intensities to an age-predicted HRmax.
Barbara E. Ainsworth, Robert G. McMurray and Susan K. Veazey
The purpose of this study was to determine the accuracy of two submaximal exercise tests, the Sitting-Chair Step Test (Smith & Gilligan. 1983) and the Modified Step Test (Amundsen, DeVahl, & Ellingham, 1989) to predict peak oxygen uptake (VO2 peak) in 28 adults ages 60 to 85 years. VO2 peak was measured by indirect calorimetry during a treadmill maximal graded exercise test (VO2 peak, range 11.6–31.1 ml · kg −l · min−1). In each of the submaximal tests, VO2 was predicted by plotting stage-by-stage submaximal heart rate (HR) and perceived exertion (RPE) data against VO2 for each stage and extrapolating the data to respective age-predicted maximal HR or RPE values. In the Sitting-Chair Step Test (n = 23), no significant differences were observed between measured and predicted VO2 peak values (p > .05). However, predicted VO2 peak values from the HR were 4.3 ml · kg−1 · min−1 higher than VO2 peak values predicted from the RPE data (p < .05). In the Modified Step Test (n = 22), no significant differences were observed between measured and predicted VO2 peak values (p > .05). Predictive accuracy was modest, explaining 49–78% of the variance in VO2 peak. These data suggest that the Sitting-Chair Step Test and the Modified Step Test have moderate validity in predicting VO2 peak in older men and women.
Katherine E. Robben, David C. Poole and Craig A. Harms
A two-test protocol (incremental/ramp (IWT) + supramaximal constant-load (CWR)) to affirm max and obviate reliance on secondary criteria has only been validated in highly fit children. In girls (n = 15) and boys (n = 12) with a wide range of VO2max (17–47 ml/kg/min), we hypothesized that this procedure would evince a VO2-WR plateau and unambiguous VO2max even in the presence of expiratory flow limitation (EFL). A plateau in the VO2-work rate relationship occurred in 75% of subjects irrespective of EFL There was a range in RER at max exercise for girls (0.97–1.14; mean 1.06 ± 0.04) and boys (0.98−1.09; mean 1.03 ± 0.03) such that 3/15 girls and 2/12 boys did not achieve the criterion RER. Moreover, in girls with RER > 1.0 it would have been possible to achieve this criterion at 78% VO2max. Boys achieved 92% VO2max at RER = 1.0. This was true also for HRmax where 8/15 girls’ and 6/12 boys’ VO2max would have been rejected based on HRmax being < 90% of age-predicted HRmax. In those who achieved the HRmax criterion, it represented a VO2 of 86% (girls) and 87% (boys) VO2max. We conclude that this two-test protocol confirms VO2max in children across a threefold range of VO2max irrespective of EFL and circumvents reliance on secondary criteria.
Gabriela Fischer, Pedro Figueiredo and Luca P. Ardigò
To investigate physiological performance determinants of the partial laps and an overall 22-km handbiking (HB) time trial in athletes with high paraplegia.
Seven male HB athletes with spinal cord injury (lesion levels thoracic 2-8) performed a laboratory maximal incremental test under cardiorespiratory-mechanical monitoring including respiratory-exchange ratio (RER), oxygen uptake (V̇O2), and mechanical power output (PO). Individual first and second ventilatory thresholds (V̇O2VT1 and V̇O2VT2), V̇O2peak, and POpeak were posteriorly identified. Athletes also performed a simulated HB time trial along a 4-lap bike circuit under cardiorespiratory measurement. Overall metabolic cost (C) and %V̇O2peak (ratio of V̇O2 to V̇O2peak) were calculated from race data. Race performance was defined as mean race velocity (v).
athletes completed the 22-km HB time trial in 45 ± 6 min, at 29.9 ± 3.6 km/h, with %V̇O2peak = 0.86 ± 0.10 and RER = 1.07 ± 0.17. V̇O2peak (r = .89, P = .01), POpeak (r = .85, P = .02), V̇O2VT1 (r = .96, P = .001), V̇O2VT2 (r = .92, P = .003), and C (2nd lap, r = .78; 3rd lap, r = .80; and 4th lap, r = .80) were significantly (P < .05) positively correlated with race performance. Within-subjects correlation coefficient revealed a large and significant (r = .68, P < .001) relationship between %V̇O2peak and v.
V̇O2peak, POpeak, ventilatory thresholds, %V̇O2peak, and C appeared to be important physiological performance determinants of HB time trial.
David M. Shaw, Fabrice Merien, Andrea Braakhuis, Daniel Plews, Paul Laursen and Deborah K. Dulson
least 12 months and without a history of recurrent gastrointestinal symptoms volunteered to participate in the study (age, 26.7 ± 5.2 years; body mass, 69.6 ± 8.4 kg; height, 1.82 ± 0.09 m; body mass index, 21.2 ± 1.5 kg/m 2 ; VO 2 peak, 63.9 ± 2.5 ml·kg −1 ·min −1 ; W max, 389.3 ± 50.4 W; hours
Bo Fernhall, Wendy Kohrt, Lee N. Burkett and Steven Walters
This study evaluated the relationship between run performance, lactate threshold (LT), VO2max, and running economy in adolescent boys (n = 11) and girls (n = 10). Subjects completed laboratory tests to establish VO2max, LT, and running economy. The race performance was the finish time from a cross-country meet. The boys exhibited higher VO2max (67.7 vs. 54.6 ml · kg−1 · min−1) and VO2 at LT (61.7 vs. 48.4 ml · kg−1 · min−1) compared with the girls (p < .05), but there was no difference in running economy, peak lactate, or the %VO2max at LT (p > .05). VO2max (r = −.70) and VO2 at LT (r = −.74) were significantly correlated to performance for the boys, but running economy was not (r = .10). For the girls, VO2max (r = −.90), VO2 at LT (r = −.77), and running economy (r = −.86) were all significantly related to performance. LT was important for cross-country run performance. However, VO2max was an equally strong or better predictor than either LT or running economy.