The effect of blood flow restriction in low-intensity load exercise on isokinetic strength of the quadriceps muscles in knee osteoarthritis

Introduction: Cartilage destruction in knee osteoarthritis (KOA) caused the inflammation process. It makes the patient complain of knee pain, tends to immobilize, and induced neural inhibition (Arthrogenic muscle inhibition) on the quadriceps muscle as a knee stabilator and shock absorbent. These caused quadriceps weakness. The combination of blood flow restriction (BFR) and low-intensity resistance training (LIRT) showed an improvement in isotonic peak torque significantly, but the prescription is varied and limited in Indonesia. Patient and Methods: This was a clinical experimental study with randomized control trial with pre and post-test design. The subjects were 28 KOA patients (50-70 years old). The intervention group (n=14) received a combination of low-load resistance training (30% 1-RM; 75 repetitions) and BFR (50 mmHg). The control group (n=14) received low load resistance training only (30% 1-RM; 75 repetitions). Both groups received training 2 times per week with a Q-bench machine for 6 weeks. Isokinetic peak torque was assessed before and after the training program. Results: There was a significant improvement in isokinetic peak torque before and after the training program in both groups (intervention group p=0.001; control group p=0.000). There was a significant improvement of delta isokinetic peak torque between both groups (p=0.018) and post-test between both groups (p=0.044). The effect size value of the intervention group was 1.22 (very large) and the control group was 0.89 (large). Conclusions: The addition of BFR on LIRT for 6 weeks can improve isokinetic quadriceps strength in patients with knee osteoarthritis.