Raphael Faiss, Claudia von Orelli, Olivier Dériaz and Grégoire P. Millet
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.
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.
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).
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.
Cyril Besson, Martin Buchheit, Manu Praz, Olivier Dériaz and Grégoire P. Millet
In this study, the authors compared the cardiorespiratory responses between the 30–15 Intermittent Ice Test (30-15IIT) and the 30–15 Intermittent Fitness Test (30-15IFT) in semiprofessional hockey players.
Ten players (age 24 ± 6 y) from a Swiss League B team performed the 30-15IIT and 30-15IFT in random order (13 ± 4 d between trials). Cardiorespiratory variables were measured with a portable gas analyzer. Ventilatory threshold (VT), respiratory-compensation point (RCP), and maximal speeds were measured for both tests. Peak blood lactate ([Lapeak]) was measured at 1 min postexercise.
Compared with 30-15IFT, 30-15IIT peak heart rate (HRpeak; mean ± SD 185 ± 7 vs 189 ± 10 beats/min, P = .02) and peak oxygen consumption (VO2peak; 60 ± 7 vs 62.7 ± 4 mL/min/kg, P = .02) were lower, whereas [Lapeak] was higher (10.9 ± 1 vs 8.6 ± 2 mmol/L, P < .01) for the 30–15IIT. VT and RCP values during the 30-15IIT and 30-15IFT were similar for %HRpeak (76.3% ± 5% vs 75.5% ± 3%, P = .53, and 90.6% ± 3% vs. 89.8% ± 3%, P = .45) and % VO2peak (62.3% ± 5% vs 64.2% ± 6%, P = .46, and 85.9% ± 5% vs 84.0% ± 7%, P = .33). VO2peak (r = .93, P < .001), HRpeak (r = .86, P = .001), and final velocities (r = .69, P = .029) were all largely to almost perfectly correlated.
Despite slightly lower maximal cardiorespiratory responses than in the field-running version of the test, the on-ice 30-15IIT is of practical interest since it is a specific maximal test with a higher anaerobic component.