We appreciate the comments on our article “The addition of blood flow restriction to resistance exercise in individuals with knee pain: a systematic review and meta-analysis” (Cuyul-Vásquez et al.1). We would like to take the opportunity to address several points raised in these comments.

First, it is important to consider that performing subgroup analyses for meta-analysis with less than 10 studies and with high heterogeneity among the included studies, is not recommended.2,3 In our meta-analysis for pain intensity, the small number of included clinical trials (n = 5), the considerable heterogeneity (i2 = 76%) of these trials, and the lack of plausible interaction, justify our decision not to report a subgroup analysis. We understand how the contrast between the results of previous investigations and the findings of our study could be questioned. For this reason, in response to your letter, we performed a subgroup analysis for pain intensity, independently combining studies that used high intensity versus low intensity resistance exercises in the control group.

The comparison between low intensity resistance exercise (30%-1RM) combined with blood flow restriction (BFR) versus high intensity resistance exercise (70% -1RM),4–6 showed no benefits of BFR for pain relief (pooled SMD = -0.08, 95% CI = -0.41, 0.26, p = 0.66, I2: 0%). For the comparison between low intensity resistance exercise (30%-1RM) with or without BFR, 4,7,8 the pooled SMD also showed no added effectiveness of BFR on pain relief (SMD= -0.51, 95% CI = -1.57, 0.55, p = 0.34, I2: 87%). Therefore, both comparisons are not statistically and clinically significant.9 While this subgroup analysis is affected by the limitations described in the first point of this letter, these findings support the conclusions of our systematic review with meta-analysis, that adding BFR to resistance exercise does not provide additional benefits to decrease knee pain.1