Effects of blood flow restriction combined with electrical stimulation on muscle functions and performance in university football players with knee osteoarthritis

The purpose of this study was to investigate the effects of combining blood flow restriction training (BFRT) with electrical muscle stimulation (EMS) on muscle functions and sports performance in football players with knee osteoarthritis (KOA). This parallel randomized controlled trial was conducted on 64 football players diagnosed with KOA at Chengdu Sport University. Participants were enrolled based on predefined eligibility criteria and randomly allocated to four groups: the control group (CTR, n = 16), BFRT-alone group (BFRT, n = 16), EMS-alone group (EMS, n = 16), and BFRT combined with EMS group (CMB, n = 16). Data were gathered via the 10-meter sprint, 20-meter sprint, countermovement jump (CMJ), and Illinois agility test (IAT) to assess sports performance. Additionally, peak torque (PT) was used to measure muscle strength, the root mean square (RMS) was used to assess muscle activation, and the cross-sectional area (CSA) was used to evaluate muscle volume. The data were statistically analyzed via SPSS software, and a p-value < 0.05 was considered significant. Following the 8-week intervention, the CMB group showed a more pronounced change in the 10-m sprint compared to the CTR group (p < 0.001) and exhibited significant differences in the 20-m sprint (CTR: p < 0.001, BFRT: p = 0.015, EMS: p < 0.001), CMJ (CTR: p < 0.001, BFRT: p = 0.019, EMS: p < 0.001), and IAT (CTR: p < 0.001, BFRT: p = 0.009, EMS: p = 0.018), outperforming the other three groups. To PT, the CMB groups demonstrated significant superiority over the other three groups (CTR: p < 0.001, BFRT: p < 0.001, EMS: p < 0.001), while the BFRT group exhibited a notable difference in PT than the EMS group (p = 0.032). Concerning RMS, the EMS and CMB groups showed significant differences from the CTR (EMS: p < 0.001, CMB: p < 0.001) and BFRT (EMS: p = 0.019, CMB: p < 0.001) groups, whereas the change in the BFRT group was more significant than that in the CTR group (p = 0.007). For CSA, the BFRT and CMB groups presented notable differences from the CTR (BFRT: p = 0.008, CMB: p = 0.002)and EMS (BFRT: p = 0.014, CMB: p = 0.004) groups. In summary, the results suggest that BFRT combined with EMS can increase muscle strength in male football players with KOA through improving muscle volume and neuromuscular recruitment under low-intensity resistance training, thereby increasing explosive power and agility.