Effects of 6-day ischaemic preconditioning on adaptations to an altitude training camp in cross-country skiers.

To determine whether ischaemic preconditioning (IPC) administered prior to an altitude training camp could enhance aerobic fitness and endurance performance in athletes. In a randomized controlled trial, 19 competitive (Tiers 3-5) cross-country (XC) skiers (V˙ O2peak 69.1 ± 6.4 ml.min-1.kg-1) performed a 6-day IPC block ( n = 10) or placebo compressions (n = 9) before a 21-day altitude camp in Park City, Utah (2,200 m) during their pre-competition season. Measures of performance and laboratory outcomes included a 3000-m track time trial, peak treadmill speed, peak O2 uptake, muscle oxygenation, ventilatory thresholds and haematological markers. V˙ O2peak improved only in IPC (2.9 ml.min-1.kg-1, 4%, p = 0.002), in direct proportion to the increase in quadriceps muscle deoxygenation (~17%, r = 0.84, p -1, p V˙ O2peak (r = -0.67, p V˙ O2peak gain from an altitude training camp in trained XC skiers, concomitant with greater muscle deoxygenation, and from similar training load. IPC may be considered as an effective and sustainable strategy for developing maximal aerobic fitness in a 'live high-train high' paradigm.