Impacts of blood flow restriction training on lower limb strength qualities in elite university football players

The primary aim of this study was to directly compare the effects of low-load (30% 1RM) blood flow restriction training (BFR), moderate-load (50% 1RM) BFR, and traditional high-load resistance training (70% 1RM) on improvements in maximal lower limb strength, rapid strength, and strength endurance in collegiate elite football players. We hypothesized that: under 50% limb occlusion pressure (LOP), blood flow restriction (BFR) training at 30% 1RM and 50% 1RM intensities elicits significantly differential effects on maximal strength, rapid force production, and strength endurance compared to traditional high-intensity resistance training (70% 1RM) in university elite football athletes. Twenty-four elite collegiate football players from Huazhong University of Science and Technology underwent stratified randomization based on strength training experience into three experimental groups:30% 1RM (maximum weight)-BFR, 50% 1RM-BFR, and traditional high-intensity resistance training (70% 1RM). All participants completed the 8-week supervised intervention, with the BFR groups additionally undergoing cuff inflation at 50% limb occlusion pressure (LOP). The maximum lower limb strength, rapid strength, and strength endurance were assessed using validated protocols before and after the intervention in all 24 athletes. Using the nonparametric Kruskal–Wallis W test for data statistics, in the 8-week maximum strength test, there were statistically significant differences (p < 0.001) among the three groups compared to the pre-test, and pairwise comparisons between the groups showed statistical differences between the 30% 1RM-BFR and traditional 70% 1RM groups, as well as between the 50% 1RM-BFR and traditional 70% 1RM groups. There was no statistical difference between the 30% 1RM-BFR and 50% 1RM-BFR groups. In the 8-week rapid strength test, all three groups showed statistical differences compared to the pre-test (p < 0.05), and there was a significant difference between 30% 1RM-BFR and 50% 1RM-BFR (p < 0.001). However, pairwise comparisons between groups did not show statistical differences. In the 8-week strength endurance test, there were significant statistical differences (p < 0.001) among the three groups compared to the pre-test. The pairwise comparison results between the groups showed differences between the 30% 1RM-BFR and 70% 1RM traditional groups, as well as between the 50% 1RM-BFR and 70% 1RM traditional groups. The results of this study indicate that over an 8-week training period, lower limb strength training combined with BFR at low loads (30% and 50% 1RM) can effectively improve lower limb strength quality in highly trained university-level football players, achieving comparable or superior gains to traditional high-intensity resistance training (70% 1RM) in specific aspects.