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Jaak Jürimäe, Kaja Haljaste, Antonio Cicchella, Evelin Lätt, Priit Purge, Aire Leppik and Toivo Jürimäe

The purpose of this study was to examine the influence of the energy cost of swimming, body composition, and technical parameters on swimming performance in young swimmers. Twenty-nine swimmers, 15 prepubertal (11.9 ± 0.3 years; Tanner Stages 1−2) and 14 pubertal (14.3 ± 1.4 years; Tanner Stages 3−4) boys participated in the study. The energy cost of swimming (Cs) and stroking parameters were assessed over maximal 400-m front-crawl swimming in a 25m swimming pool. The backward extrapolation technique was used to evaluate peak oxygen consumption (VO2peak). A stroke index (SI; m2 · s−1 · cycles−1) was calculated by multiplying the swimming speed by the stroke length. VO2peak results were compared with VO2peak test in the laboratory (bicycle, 2.86 ± 0.74 L/min, vs. in water, 2.53 ± 0.50 L/min; R2 = .713; p = .0001). Stepwise-regression analyses revealed that SI (R2 = .898), in-water VO2peak (R2 = .358), and arm span (R2 = .454) were the best predictors of swimming performance. The backward-extrapolation method could be used to assess VO2peak in young swimmers. SI, arm span, and VO2peak appear to be the major determinants of front-crawl swimming performance in young swimmers.

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Ryan D. Burns, James C. Hannon, Timothy A. Brusseau, Patricia A. Eisenman, Pedro F. Saint-Maurice, Greg J. Welk and Matthew T. Mahar

Cardiorespiratory endurance is a component of health-related fitness. FITNESSGRAM recommends the Progressive Aerobic Cardiovascular Endurance Run (PACER) or One mile Run/Walk (1MRW) to assess cardiorespiratory endurance by estimating VO2 Peak. No research has cross-validated prediction models from both PACER and 1MRW, including the New PACER Model and PACER-Mile Equivalent (PACER-MEQ) using current standards. The purpose of this study was to cross-validate prediction models from PACER and 1MRW against measured VO2 Peak in adolescents. Cardiorespiratory endurance data were collected on 90 adolescents aged 13–16 years (Mean = 14.7 ± 1.3 years; 32 girls, 52 boys) who completed the PACER and 1MRW in addition to a laboratory maximal treadmill test to measure VO2 Peak. Multiple correlations among various models with measured VO2 Peak were considered moderately strong (R = .74–0.78), and prediction error (RMSE) ranged from 5.95 ml·kg-1, min-1 to 8.27 ml·kg-1.min-1. Criterion-referenced agreement into FITNESSGRAM’s Healthy Fitness Zones was considered fair-to-good among models (Kappa = 0.31–0.62; Agreement = 75.5–89.9%; F = 0.08–0.65). In conclusion, prediction models demonstrated moderately strong linear relationships with measured VO2 Peak, fair prediction error, and fair-to-good criterion referenced agreement with measured VO2 Peak into FITNESSGRAM’s Healthy Fitness Zones.

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Michal Botek, Jakub Krejčí, Andrew J. McKune and Barbora Sládečková

in a heterogenous group of athletes. Methods Participants A total of 16 male athletes (mean [SD]; age 31.6 [8.6] y, body mass 71.5 [8.8] kg, body height 177.0 [7.2] kg, body fat 13.4% [4.4%], VO 2 max 57.2 [8.9] mL·kg −1 ·min −1 ) volunteered for this study. They followed instructions to avoid using

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Kerry McGawley and Hans-Christer Holmberg

Purpose:

Cross-country-ski races place complex demands on athletes, with events lasting between approximately 3 min and 2 h. The aim of the current study was to compare the aerobic and anaerobic measures derived from a short time trial (TT) between male and female skiers using diagonal cross-country skiing.

Methods:

Twenty-four highly trained cross-country skiers (12 male and 12 female, age 17.4 ± 1.4 y, body mass 68.2 ± 8.9 kg, height 174 ± 8 cm) participated. The submaximal VO2–speed relationship and VO2max were derived from an incremental ramp test to exhaustion (RAMP), while the accumulated oxygen deficit (AOD), peak VO2, and performance time were measured during a 600-m TT.

Results:

The female skiers took longer to complete the TT than the males (209 ± 9 s vs 166 ± 7 s, P < .001) and exhibited a lower relative anaerobic contribution (20% ± 4% vs 24% ± 3%, P = .015) and a higher fractional utilization of VO2max (84% ± 4% vs 79% ± 5%, P = .007) than males. Although there was no significant difference in AOD between the sexes (40.9 ± 9.5 and 47.3 ± 7.4 mL/kg for females and males, respectively; P = .079), the mean difference ± 90% confidence intervals of 6.4 ± 6.0 mL/kg reflected a likely practical difference (ES = 0.72). The peak VO2 during the TT was significantly higher than VO2max during the RAMP for all participants combined (62.3 ± 6.8 vs 60.5 ± 7.2 mL · kg−1 · min−1, P = .011), and the mean difference ± 90% confidence intervals of 1.8 ± 1.1 mL · kg−1 · min−1 reflected a possible practical difference (ES = 0.25).

Conclusions:

These results show that performance and physiological responses to a self-paced TT lasting approximately 3 min differ between sexes. In addition, a TT may provide a valid measure of VO2max.

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Katrina Taylor, Jeffrey Seegmiller and Chantal A. Vella

Purpose:

To determine whether a decremental protocol could elicit a higher maximal oxygen consumption (VO2max) than an incremental protocol in trained participants. A secondary aim was to examine whether cardiac-output (Q) and stroke-volume (SV) responses differed between decremental and incremental protocols in this sample.

Methods:

Nineteen runners/triathletes were randomized to either the decremental or incremental group. All participants completed an initial incremental VO2max test on a treadmill, followed by a verification phase. The incremental group completed 2 further incremental tests. The decremental group completed a second VO2max test using the decremental protocol, based on their verification phase. The decremental group then completed a final incremental test. During each test, VO2, ventilation, and heart rate were measured, and cardiac variables were estimated with thoracic bioimpedance. Repeated-measures analysis of variance was conducted with an alpha level set at .05.

Results:

There were no significant main effects for group (P = .37) or interaction (P = .10) over time (P = .45). VO2max was similar between the incremental (57.29 ± 8.94 mL · kg–1 · min–1) and decremental (60.82 ± 8.49 mL · kg–1 · min–1) groups over time. Furthermore, Q and SV were similar between the incremental (Q 22.72 ± 5.85 L/min, SV 119.64 ± 33.02 mL/beat) and decremental groups (Q 20.36 ± 4.59 L/min, SV 109.03 ± 24.27 mL/beat) across all 3 trials.

Conclusions:

The findings suggest that the decremental protocol does not elicit higher VO2max than an incremental protocol but may be used as an alternative protocol to measure VO2max in runners and triathletes.

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Shelby L. Francis, Ajay Singhvi, Eva Tsalikian, Michael J. Tansey and Kathleen F. Janz

Purpose:

Determining fitness is important when assessing adolescents with type 1 diabetes mellitus (T1DM). Submaximal tests estimate fitness, but none have been validated in this population. This study cross-validates the Ebbeling and Nemeth equations to predict fitness (VO2max (ml/kg/min)) in adolescents with T1DM.

Methods:

Adolescents with T1DM (n = 20) completed a maximal treadmill test using indirect calorimetry. Participants completed one 4-min stage between 2.0 and 4.5 mph and 5% grade (Ebbeling/Nemeth protocol). Speed and grade were then increased until exhaustion. Predicted VO2max was calculated using the Ebbeling and Nemeth equations and compared with observed VO2max using paired t tests. Pearson correlation coefficients, 95% confidence intervals, coefficients of determination (R2), and total error (TE) were calculated.

Results:

The mean observed VO2max was 47.0 ml/kg/min (SD = 6.9); the Ebbeling and Nemeth mean predictions were 42.4 (SD = 9.4) and 43.5 ml/kg/min (SD = 6.9), respectively. Paired t tests resulted in statistically significant (p < .01) mean differences between observed and predicted VO2max for both predictions. The association between the Ebbeling prediction and observed VO2max was r = .90 (95% CI = 0.76, 0.96), R 2 = .81, and TE = 6.5 ml/kg/min. The association between the Nemeth prediction and observed VO2max was r = .81 (95% CI = 0.57, 0.92), R 2 = .66, and TE = 5.6 ml/kg/min.

Conclusion:

The Nemeth submaximal treadmill protocol provides a better estimate of fitness than the Ebbeling in adolescents with T1DM.

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Michael Wilkinson, Damon Leedale-Brown and Edward M. Winter

Purpose:

This study examined the validity of a squash-specific test designed to assess endurance capability and aerobic power.

Methods:

Eight squash players and eight runners performed, in a counterbalanced order, incremental treadmill (TT) and squash-specific (ST) tests to volitional exhaustion. Breath-by-breath oxygen uptake was determined by a portable analyzer and heart rate was assessed telemetrically. Time to exhaustion was recorded.

Results:

Independent t tests revealed longer time to exhaustion for squash players on the ST than runners (775 ± 103 vs. 607 ± 81 s; P = .003) but no difference between squash players and runners in maximal oxygen uptake ( Vo2max) or maximum heart rate (HRmax). Runners exercised longer on the TT (521 ± 135 vs. 343 ± 115 s; P = .01) and achieved higher Vo2max than squash players (58.6 ± 7.5 vs. 49.6 ± 7.3 mL·kg−1·min−1; P = .03), with no group difference in HRmax. Paired t tests showed squash players achieved higher Vo2max on the ST than the TT (52.2 ± 7.1 vs. 49.6 ± 7.3 mL·kg−1·min−1; P = .02). The Vo2max and HRmax of runners did not differ between tests, nor did the HRmax of squash players. ST and TT Vo2max correlated highly in squash players and runners (r = .94, P < .001; r = .88, P = .003).

Conclusions:

The ST discriminated endurance performance between squash players and runners and elicited higher Vo2max in squash players than a nonspecifc test. The results suggest that the ST is a valid assessment of Vo2max and endurance capability in squash players.

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Philo U. Saunders, Amanda J. Cox, Will G. Hopkins and David B. Pyne

It is unclear whether physiological measures monitored in an incremental treadmill test during a training season provide useful diagnostic information about changes in distance running performance.

Purpose:

To quantify the relationship between changes in physiological measures and performance (peak running speed) over a training season.

Methods:

Well-trained distance runners (34 males; VO2max 64 ± 6 mL⋅kg-1⋅min-1, mean ± SD) completed four incremental treadmill tests over 17 wk. The tests provided values of peak running speed, VO2max, running economy, and lactate threshold (as speed and %VO2max). The physiological measures were included in simple and multiple linear regression models to quantify the relationship between changes in these measures and changes in peak speed.

Results:

The typical within-subject variation in peak speed from test to test was 2.5%, whereas those for physiological measures were VO2max (mL⋅min-1⋅kg-1) 3.0%, economy (m⋅kg⋅mL–1) 3.6%, lactate threshold (%VO2max) 8.7%, and body mass 1.8%. In simple models these typical changes predicted the following changes in performance: VO2max 1.4%, economy 0.8%, lactate threshold –0.3%, and body mass –0.2% (90% confidence limits ~±0.7%); the corresponding correlations with performance were 0.57, 0.33, –0.05, and –0.13 respectively (~±0.20). In a multiple linear regression model, the contribution of each physiological variable to performance changed little after adjustment for the other variables.

Conclusion:

Change in VO2max in an incremental test during a running season is a good predictor of change in peak running speed, change in running economy is a moderate predictor, and lactate threshold and body mass provide little additional information.

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Vanessa Martínez-Lagunas and Ulrich Hartmann

Purpose:

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).

Methods:

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).

Results:

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%).

Conclusions:

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.

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Nicolas Fabre, Laurent Mourot, Livio Zerbini, Barbara Pellegrini, Lorenzo Bortolan and Federico Schena

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.