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Raphael Faiss, Claudia von Orelli, Olivier Dériaz and Grégoire P. Millet

Purpose:

Hypoxia is known to reduce maximal oxygen uptake (VO2max) more in trained than in untrained subjects in several lowland sports. Ski mountaineering is practiced mainly at altitude, so elite ski mountaineers spend significantly longer training duration at altitude than their lower-level counterparts. Since acclimatization in hypobaric hypoxia is effective, the authors hypothesized that elite ski mountaineers would exhibit a VO2max decrement in hypoxia similar to that of recreational ski mountaineers.

Methods:

Eleven elite (E, Swiss national team) and 12 recreational (R) ski mountaineers completed an incremental treadmill test to exhaustion in normobaric hypoxia (H, 3000 m, FIO2 14.6% ± 0.1%) and in normoxia (N, 485 m, FIO2 20.9% ± 0.0%). Pulse oxygen saturation in blood (SpO2), VO2max, minute ventilation, and heart rate were recorded.

Results:

At rest, hypoxic ventilatory response was higher (P < .05) in E than in R (1.4 ± 1.9 vs 0.3 ± 0.6 L · min−1 · kg−1). At maximal intensity, SpO2 was significantly lower (P < .01) in E than in R, both in N (91.1% ± 3.3% vs 94.3% ± 2.3%) and in H (76.4% ± 5.4% vs 82.3% ± 3.5%). In both groups, SpO2 was lower (P < .01) in H. Between N and H, VO2max decreased to a greater extent (P < .05) in E than in R (–18% and –12%, P < .01). In E only, the VO2max decrement was significantly correlated with the SpO2 decrement (r = .74, P < .01) but also with VO2max measured in N (r = .64, P < .05).

Conclusion:

Despite a probable better acclimatization to altitude, VO2max was more reduced in E than in R ski mountaineers, confirming previous results observed in lowlander E athletes.

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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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Stephen J. Bailey, Anni Vanhatalo, Matthew I. Black, Fred J. DiMenna and Andrew M. Jones

Purpose:

To assess whether combining prior “priming” exercise with an all-out pacing strategy is more effective at improving oxygen-uptake (V̇O2) kinetics and cycling performance than either intervention administered independently.

Methods:

Nine men completed target-work cycling performance trials using a self-paced or all-out pacing strategy with or without prior severe-intensity (70%Δ) priming exercise. Breath-by-breath pulmonary V̇O2 and cycling power output were measured during all trials.

Results:

Compared with the self-paced unprimed control trial (22 ± 5 s), the V̇O2 mean response time (MRT) was shorter (V̇O2 kinetics were faster) with all-out pacing (17 ± 4 s) and priming (17 ± 3 s), with the lowest V̇O2 MRT observed when all-out pacing and priming were combined (15 ± 4 s) (P < .05). However, total O2 consumed and end-exercise V̇O2 were only higher than the control condition in the primed trials (P < .05). Similarly, cycling performance was improved compared with control (98 ± 11 s) in the self-paced primed (93 ± 8 s) and all-out primed (92 ± 8 s) trials (P < .05) but not the all-out unprimed trial (97 ± 5 s; P > .05).

Conclusions:

These findings suggest that combining an all-out start with severe-intensity priming exercise additively improves V̇O2 MRT but not total O2 consumption and cycling performance since these were improved by a similar magnitude in both primed trials relative to the self-paced unprimed control condition. Therefore, these results support the use of priming exercise as a precompetition intervention to improve oxidative metabolism and performance during short-duration high-intensity cycling exercise, independent of the pacing strategy adopted.

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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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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.

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Andrew M. Murray, Joong Hyun Ryu, John Sproule, Anthony P. Turner, Phil Graham-Smith and Marco Cardinale

Purpose:

Running performance is influenced by the interaction of biomechanical and physiological factors. Miniaturized accelerometers worn by athletes can be used to quantify mechanical aspects of running and as a noninvasive tool to assess training status and progression. The aim of this study was to define and validate a method to assess running regularity and allow the estimation of an individual’s oxygen uptake (V̇O2) and/or blood lactate—[La]b—based on data collected with accelerometers and heart rate.

Methods:

Male adolescent endurance athletes completed an incremental submaximal aerobic stage test where V̇O2 and [La]b were measured. The test was terminated when [La]b concentration at the end of the stage exceeded 4 mmol/L. Two wireless triaxial accelerometers were placed on participants’ right shank and lower back throughout the test. The root mean square (RMS) and sample entropy (SampEn) were calculated for the vertical, mediolateral, and anteroposterior components of acceleration.

Results:

There were significant positive correlations of acceleration and entropy variables with [La]b and V̇O2, with moderate to high coefficients (r = .43–.87). RMS of the shank acceleration was the most highly related with both physiological variables. When the accelerometer was attached on the trunk, SampEn of the vertical acceleration had the strongest relationship with V̇O2 (r = .76, P < .01).

Conclusions:

The described method analyzing running complexity may allow an assessment of gait variability, which noninvasively tracks V̇O2 and/or [La]b, allowing monitoring of fatigue or training readiness for trained adolescent individuals.

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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.

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Thomas Losnegard, Martin Andersen, Matt Spencer and Jostein Hallén

Purpose:

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.

Methods:

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.

Results:

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.

Conclusions:

Neither passive recovery nor running at ~58% of VO2peak between 2 heats changed performance significantly.

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Humberto M. Carvalho, Manuel J. Coelho-e-Silva, Joey C. Eisenmann and Robert M. Malina

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.