Purpose: Exercise increases pressor pain thresholds in pain-free individuals, known as exercise-induced hypoalgesia. Exercise with blood flow restriction can produce higher hypoalgesic responses, but the effect of exercise with blood flow restriction on hypoalgesia in patients with patellofemoral pain is unknown. The main aim of this study was to compare the immediate effect of exercise with blood flow restriction on quadriceps muscle hypoalgesia in patients with patellofemoral pain.

Methods: Fifty-two patients with patellofemoral pain (based on inclusion criteria) were randomly divided into two groups of isometric squat training with and without blood flow restriction (26 people in each group). The group without blood flow restriction was included in the study as the control group. Pressure pain threshold in the quadriceps muscles was evaluated with a dynamometer and pain tolerance in the leg was evaluated using Algorometry of hand-controlled cuff before and after the intervention.

Results: The change in the pressure threshold of the quadriceps muscle after squat training did not show much difference between the two groups. The squat group with blood flow restriction had a 18.99% increase in quadriceps pain threshold, while the group without blood flow restriction had a 16.55% increase. But the change in pressure pain tolerance in the squat group with blood flow restriction was 7.7% higher than the squat group without blood flow restriction.

Conclusion: Exercise with blood flow restriction compared to exercise without blood flow restriction caused more hypoalgesia in patients with patellofemoral pain. Therefore, this training method can be used as an effective therapeutic intervention for hypoalgesia in patients with this syndrome.