Effects of interval training with and without blood flow restriction on well-being, perceived exertion, and performance in national-level male academy soccer players: a 6-week randomised controlled trial

Blood flow restriction (BFR) combines low-load strength and aerobic exercise to improve athletic performance. This study examined the effects of interval running with and without BFR (IR-BFR; IR) on well-being, RPE and performance in soccer players. Players (16.1 ± 0.6 years; 21.1 ± 1.0 kg/m2) were randomly allocated to IR-BFR or IR. Training consisted of 4 × 5 min runs at 50–60% maximal aerobic speed. Well-being (fatigue, sleep, soreness, stress, mood, Hooper Index [HI]) and RPE were monitored daily. CMJ, maximal aerobic speed, repeated sprint ability, and VO2max, assessed pre- and post. IR-BFR showed lower HI at week 1 (p < 0.01) but higher at week 3 (p < 0.05) compared with IR. Within IR-BFR, HI was lowest at week 1 versus weeks 3, 5, and 6 (p < 0.05). No significant differences were found in RPE or performance variables (p > 0.05). However, moderate effect sizes favoured the IR-BFR group for CMJ best (Cohen’s dunbiased = 0.55, 95% CI [−0.36, 1.48]) and Vmax (Cohen’s dunbiased = 0.68, 95% CI [−0.23, 1.64]). IR with BFR may initially reduce well-being but improve over time. CMJ and Vmax tended to favour IR-BFR, without differences, and should be interpreted cautiously given the wide CIs.