M Buchheit, S Racinais, J Bilsborough, J Hocking, A Mendez-Villanueva, P C Bourdon, S Voss, S Livingston, R Christian, J Périard, J Cordy, A J Coutts
ABSTRACT
Objectives: To examine with a parallel group study design the performance and physiological responses to a 14-day off-season ‘live high-train low in the heat’ training camp in elite football players.
Methods: Seventeen professional Australian Rules Football players participated in outdoor football-specific skills (32±1°C, 11.5 h) and indoor strength (23±1°C, 9.3 h) sessions and slept (12 nights) and cycled indoors (4.3 h) in either normal air (NORM, n=8) or normobaric hypoxia (14±1 h/day, FiO2 15.2–14.3%, corresponding to a simulated altitude of 2500–3000 m, hypoxic (HYP, n=9). They completed the Yo-Yo Intermittent Recovery level 2 (Yo-YoIR2) in temperate conditions (23±1°C, normal air) precamp (Pre) and postcamp (Post). Plasma volume (PV) and haemoglobin mass (Hbmass) were measured at similar times and 4 weeks postcamp (4WPost). Sweat sodium concentration ((Na+)sweat) was measured Pre and Post during a heat-response test (44°C).
Results: Both groups showed very large improvements in Yo-YoIR2 at Post (+44%; 90% CL 38, 50), with no between-group differences in the changes (−1%; −9, 9). Postcamp, large changes in PV (+5.6%; −1.8, 5.6) and (Na+ )sweat (−29%; −37, −19) were observed in both groups, while Hbmass only moderately increased in HYP (+2.6%; 0.5, 4.5). At 4WPost, there was a likely slightly greater increase in Hbmass (+4.6%; 0.0, 9.3) and PV (+6%; −5, 18, unclear) in HYP than in NORM.
Conclusions: The combination of heat and hypoxic exposure during sleep/training might offer a promising ‘conditioning cocktail’ in team sports.
INTRODUCTION
Along with the technical and tactical aspects of the game, well-developed physical capacities such as sprinting speed, acceleration/deceleration, maximal aerobic power and repeated-sprint performance are desirable for successful participation in elite level team sports such as Australian Rules football (AF). However, because training schedules are often crowded in many professional team sports, coaches often seek training strategies that concurrently target players’ physical fitness, technical and tactical skills. Additionally, with sports that have inter-
national competition schedules, teams are often required to play in extreme environments, including altitude (eg, 2010 Soccer World Cup in South Africa) and/or high temperatures and humidity (eg, 2008 Olympics in China). For these reasons, the use of hypoxic exposure including living high-training low model5 or living high-train low and high, interspersed and/or heat training has gained popularity. Both these methods have the potential to improve the ability to perform at high intensity in the environment of interest, elicit physiological adaptations that might translate into increased physical performance even in ‘normal’ environmental conditions and save time for technical training as many of the purported adaptations are deemed to occur without altering the tactical contents of the training sessions (ie, the players get the environmental stimuli during their sleep (sleep high-train low model (LHTL)) and/or while simply playing in the heat.