The LH-TL training has been found not to reduce the energy cost in normoxia (Levine and StrayGundersen, 1997; Telford et al., 1996), but in several studies (Gore et al., 2001; Katayama et al., 2003; Marconi et al., 2005; Neya et al., 2007; Saunders et al., 2004b; Schmidt et al.
(2006) energy cost of exercise did not change immediately after LH-TL protocol but 15 days later was reduced in the non-specific activity.
One of the more interesting modifications in the LH-TL protocol was proposed by Chapman et al.
The athletes from the H group beside the LH-TL procedure performed specific aerobic endurance training in hypoxia.
In case of LH-TH and LH-TL training, two factors are considered to be responsible for improvement of hematological variables, e.g.
These results suggest that, altitude between 2,000 and 2,500 m during the LH-TL protocol allows for an optimal acclimatization response for sea level performance.
Contrary, in several experiments with the LH-TL protocol where the subjects' exposure to hypoxia was extended to 250 hours or longer (300-550 h) haemoglobin mass increased significantly by 8-10% (Brugniaux et al., 2006; Schmidt et al., 2002), and 4-7% (Clark et al., 2009; Friedmann et al., 2005; Gough et al., 2012; Rusko et al., 1999; Wehrlin et al., 2006), respectively.
Neither maximal capacity of oxidative phosphorylation nor mitochondrial efficiency was modified by time or LH-TL procedure.
The Hi-Lo or LH-TL model combines living at high altitude with daily sojourns to lower altitudes for training.
In the literature reviewed, the evidence suggest that the Hi-Lo or LH-TL model has advantages over SL training to improve performance, associated with an increase in V[O.sub.2max], haematological parameters, power output and economy.