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Philo U. Saunders, Laura A. Garvican-Lewis, Robert F. Chapman and Julien D. Périard

respective events. The IAAF World Cross Country Championships in 2015 (Guiyang, China; elevation 1,275 m) and 2017 (Kampala, Uganda; elevation 1,210 m) were held at altitudes high enough to significantly impair aerobic performance. In the consensus statement, we will briefly discuss the physiological effects

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Amelia J. Carr, Laura A. Garvican-Lewis, Brent S. Vallance, Andrew P. Drake, Philo U. Saunders, Clare E. Humberstone and Christopher J. Gore

For some elite endurance athletes, major races are held at altitude. 1 , 2 Competing even at low altitudes, classified as 500 to 2000 m, 3 can affect performances. 4 For instance, the International Association of Athletics Federations classifies events held at any elevation >1000 m as being

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Dennis van Erck, Eric J. Wenker, Koen Levels, Carl Foster, Jos J. de Koning and Dionne A. Noordhof

To find the optimal altitude for each sporting event, it is important to know the effect of altitude on the main variables that determine performance. The main performance-determining variables, according to the model of Joyner and Coyle, 1 are performance oxygen uptake ( V ˙ O 2 ; determined by

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Ben J. Lee and Charles Douglas Thake

known reductions in aerobic power associated with exercise at altitude, 12 – 14 a given intensity of work represents a greater relative intensity (higher percentage of V ˙ O 2 max ) when exercise is performed under hypoxic conditions. Therefore, greater physiological and metabolic adjustments are

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Blake D. McLean, Kevin White, Christopher J. Gore and Justin Kemp

Many high-intensity, intermittent team sports undertake prolonged preseason training, which is important for developing physical capacities essential for competitive success. Environmental stimuli, such as altitude 1 or heat, 2 have been applied during these periods, in an attempt to enhance

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Ray M. Merrill

altitude), as well as urban residency, poverty, tobacco smoking, and obesity, have been associated with physical activity. The influence of these variables on physical activity may be direct or indirect. Associations may also be modified by other variables such as gender. A direct effect of air temperature

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Ida A. Heikura, Louise M. Burke, Dan Bergland, Arja L.T. Uusitalo, Antti A. Mero and Trent Stellingwerff

Many high-performance endurance athletes undertake specialized forms of altitude training. The lack of agreement regarding the effects of altitude training on hematology and performance is partially explained by various differences in the methodology of altitude training studies. 1 For example

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Lindsey E. Miller, Graham R. McGinnis, Brian Kliszczewicz, Dustin Slivka, Walter Hailes, John Cuddy, Charles Dumke, Brent Ruby and John C. Quindry

Oxidative stress occurs as a result of altitude-induced hypobaric hypoxia and physical exercise. The effect of exercise on oxidative stress under hypobaric hypoxia is not well understood.

Purpose:

To determine the effect of high-altitude exercise on blood oxidative stress. Nine male participants completed a 2-d trek up and down Mt Rainer, in North America, at a peak altitude of 4,393 m. Day 1 consisted of steady-pace climbing for 6.25 hr to a final elevation of 3,000 m. The 4,393-m summit was reached on Day 2 in approximately 5 hr. Climb–rest intervals varied but were consistent between participants, with approximately 14 hr of total time including rest periods. Blood samples were assayed for biomarkers of oxidative stress and antioxidant potential at the following time points: Pre (before the trek), 3Kup (at ascent to 3,000 m), 3Kdown (at 3,000 m on the descent), and Post (posttrek at base elevation). Blood serum variables included ferric-reducing antioxidant potential (FRAP), Trolox equivalent antioxidant capacity (TEAC), protein carbonyls (PC), and lipid hydroperoxides. Serum FRAP was elevated at 3Kup and 3Kdown compared with Pre and Post values (p = .004, 8% and 11% increase from Pre). Serum TEAC values were increased at 3Kdown and Post (p = .032, 10% and 18% increase from Pre). Serum PC were elevated at 3Kup and 3Kdown time points (p = .034, 194% and 138% increase from Pre), while lipid hydroperoxides were elevated Post only (p = .004, 257% increase from Pre).

Conclusions:

Findings indicate that high-altitude trekking is associated with increased blood oxidative stress.

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Laura A. Garvican, Kristal Hammond, Matthew C. Varley, Christopher J. Gore, Francois Billaut and Robert J. Aughey

Purpose:

This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements.

Methods:

Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01–4.16 m/s; HiVR, 4.17–10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals.

Results:

Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES –0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES –0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (–0.47 ± 0.59), with no clear effect of altitude at d 6 (–0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt.

Conclusion:

Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.

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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.