Effects of High Intensity Interval Training in Normobaric Hypoxia on Aerobic Performance and Exercise-Induced Motor Performance Fatigue in Young Biathletes

Table 2. Changes in hypoxia-induced markers and biomarkers of skeletal muscle before (pre) and after (post) 3 weeks of exercise training in normoxia (NT) and hypoxia (HT).

Variables		NT, n=12		HT, n=12		Main effects (p-value, ηp²)
Variables		Pre	Post	Pre	Post	Ox	T	Ex	Ox*T	Ox*Ex	T*Ex	OxTEx
HIF-1α [ng/mL]	rest	0.7 ± 0.4	0.5 ± 0.2	0.5 ± 0.4	0.5 ± 0.3	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
HIF-1α [ng/mL]	max	0.8 ± 0.8	0.6 ± 0.3	0.6 ± 0.4	1.2 ± 0.5	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
VEGF [ng/mL]	rest	41.5 ± 21.8	46.8 ± 32.1	42.5 ± 25.0	62.4 ± 25.0	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
VEGF [ng/mL]	max	51.5 ± 16.4	50.7 ± 22.5	60.1 ± 16.8	81.7 ± 16.8*	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
CK [U/L]	rest	130.9 ± 61.2	134.5 ± 60.3	132.2 ± 34.0	125.9 ± 31.6	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
CK [U/L]	max	164.3 ± 77.4	177.3 ± 77.8	166.8 ± 57.4	145.7 ± 41.3##	0.359 (0.080)	0.778 (0.008)	0.005 (0.526)	0.162 (0.170)	0.351 (0.079)	0.654 (0.019)	0.050 (0.310)
LDH [U/L]	rest	353.8 ± 49.8	361.2 ± 42.2	358.3 ± 33.9	334.1 ± 42.9	0.140 (0.187)	0.050 (0.041)	0.000 (0.844)	0.152 (0.177)	0.852 (0.003)	0.630 (0.022)	0.232 (0.127)
LDH [U/L]	max	398.8 ± 54.0	411.6 ± 52.9	418 ± 50.7	375.5 ± 48.8**##	0.140 (0.187)	0.050 (0.041)	0.000 (0.844)	0.152 (0.177)	0.852 (0.003)	0.630 (0.022)	0.232 (0.127)
TN [ng/mL]	rest	1.6 ± 0.5	1.6 ± 0.9	1.8 ± 1.2	2.0 ± 1.0	0.060 (0.286)	0.077 (0.257)	0.001 (0.647)	0.940 (0.001)	0.743 (0.010)	0.857 (0.003)	0.996 (0.000)
TN [ng/mL]	max	1.8 ± 1.0	2.0 ± 1.5	1.9 ± 1.4	2.4 ± 0.9	0.060 (0.286)	0.077 (0.257)	0.001 (0.647)	0.940 (0.001)	0.743 (0.010)	0.857 (0.003)	0.996 (0.000)
Mb [ng/mL]	rest	38.4 ± 5.2	37.8 ± 7.2	38.5 ± 5.8	35.6 ± 7.6	0.083 (0.248)	0.625 (0.022)	0.000 (0.882)	0.001 (0.617)	0.062 (0.281)	0.414 (0.062)	0.001 (0.647)
Mb [ng/mL]	max	42.7 ± 11.7	54.7 ± 11.8	47.2 ± 8.6	35.9 ± 12.2*###	0.083 (0.248)	0.625 (0.022)	0.000 (0.882)	0.001 (0.617)	0.062 (0.281)	0.414 (0.062)	0.001 (0.647)

HIF-1α - hypoxia-inducible factor 1 alpha; VEGF - vascular endothelial growth factor; CK - creatine kinase; LDH - lactate dehydrogenase; TN -troponin; Mb - myoglobin; rest – at baseline; max – immediately after graded exercise test. Ox-oxygen conditions; T-training and Ex-exercise effects. Data are means and SD.*p < 0.05,** p < 0.01 significant differences between post HT vs. pre HT;#p < 0.05,##p < 0.01,###p < 0.001 significant differences between post-HT vs. post-NT.