Low-load resistance exercise training with reduced muscle blood flow (ischemic training) has been shown to induce gains in muscle mass and strength comparable to heavy-load training (Takarada et al., 2000; Abe et al., 2006). As we recently demonstrated, it can also enhances muscle endurance and oxygen delivery (Kacin & Strazar, 2011), which may be useful in preventing muscle atrophy and deconditioning after joint injury or surgery. However, vascular occlusion with cuffs is limited to extremities and may augment oedema formation, compress nerves and induce discomfort. Given that short-term hypoxia is most likely a key trigger for adaptation, we hypothesised that inhalation of normobaric hypoxic gas mixture during low-load resistance exercise can give similar results with fewer hindrances. Seven healthy males performed knee-extension exercise for 4 weeks (4 sessions a week) at 15% 1RM. Subjects trained one leg (H-leg) while inhaling hypoxic gas mixture (FO2 = 12 %), whereas the other leg (N-leg) was trained in normoxic conditions. Values are means ± S.D., compared by ANOVA. Levels of mixed blood oxygen saturation were 84±2 % and 97±1 % during hypoxic and normoxic exercise, respectively. After training, no significant increase in quadriceps maximal voluntary isometric contraction force at 90° of flexion and cross-sectional area (MRI) on either of the two legs was observed. Number of full-ROM knee extensions at 15% 1RM to failure (endurance test) increased (P<0.01) by 28±5 % in H-leg and 34±5 % in N-leg when performed in normoxia, and 22±6 % in H-leg and 26±5 % in N-leg when performed in hypoxia.Exercise-induced decrease in oxygenated haemoglobin concentration (near-infrared spectroscopy) in v. lateralis muscle during normoxic endurance tests was attenuated (P<0.025) by 5.69±0.51 μM % in H-leg and 5.57±0.44 μM in N-leg, whereas total haemoglobin concentration was increased (P<0.025) in by 5.52±0.28 μM % in H-leg and 5.02±0.24 μM in N-leg. A transient increase (P<0.05) in RMS EMG amplitude of rectus f. was noted in both legs during the normoxic endurance test. In conclusion, inhaling hypoxic gas mixture during low-load resistance exercise does not enhance muscle mass, performance, activation or oxygen delivery more than exercise performed in normoxia. Exercise stimuli for positive muscle adaptation during short-term hypoxic exercise training is clearly not comparable to the stimuli induced by equal ischemic exercise training (Kacin & Strazar, 2011). Differences in level of tissue hypoxia and local metabolite accumulation may play an important role in this regard.