Effects of low-load resistance training combined with blood flow restriction or hypoxia on muscle function and performance in netball athletes

Objectives To investigate the effect of blood flow restriction or normobaric hypoxic exposure combined with low-load resistant exercise (LRE), on muscular strength and endurance. Design A randomised controlled trial. Methods Well-trained netball players (n = 30) took part in a 5 weeks training of knee flexor and extensor muscles in which LRE (20% of one repetition maximum) was combined with (1) an occlusion pressure of approximately 230 mmHg around the upper thigh (KT, n = 10), (2) hypoxic air to generate blood oxyhaemoglobin levels of approximately 80% (HT, n = 10) or (3) with no additional stimulus (CT, n = 10). The training was of the same intensity and amount in all groups. One to five days before and after training, participants performed a series of strength and endurance tests of the lower limbs (3-s maximal voluntary contraction [MVC₃], area under 30-s force curve [MVC₃₀], number of repetitions at 20% 1RM [Reps201RM]). In addition, the cross-sectional area (CSA) of the quadriceps and hamstrings were measured. Results Relative to CT, KT and HT increased MVC₃ (11.0 ± 11.9% and 15.0 ± 13.1%), MVC₃₀ (10.2 ± 9.0% and 18.3 ± 17.4%) and Reps201RM (28.9 ± 23.7% and 23.3 ± 24.0%, mean ± 90% confidence interval) after training. CSA increased by 6.6 ± 4.5%, 6.1 ± 5.1% and 2.9 ± 2.7% in the KT, HT and CT groups respectively. Conclusions LRE in conjunction with KT or HT can provide substantial improvements in muscle strength and endurance and may be useful alternatives to traditional training practices