Low load resistance training with blood flow restriction decreases anterior knee pain more than resistance training alone. A pilot randomised controlled trial

Objectives: To evaluate if application of blood flow restriction (BFR) combined with low-load resistance training (LLRT) would induce significant anterior knee pain (AKP) reduction compared to LLRT alone.

Design: Randomised Controlled Trial.

Setting: Institutional physiotherapy clinic.

Participants: Forty males suffering from AKP were randomly allocated in the LLRT-BFR or LLRT group. BFR was applied at 80% of complete vascular occlusion. Four sets of open kinetic chain knee extensions were implemented in both groups using a pain monitoring model.

Main outcome measures: Pain (0-10) was assessed immediately after LLRT-BFR or LLRT application and after a physiotherapy session (45 min) during shallow and deep single-leg squat (SLS_S, SLS_D), and step-down test (SDT).

Results: Significant immediate pain reduction was found in LLRT-BFR group in SLS_S, SLS_D and SDT (d = 1.32, d = 1.12, d = 0.88 respectively), but no difference was found in LLRT group. Following the physiotherapy session pain reduction was sustained in LLRT-BFR group in both SLSs and SDT (d = 1.32, d = 0.78, d = 0.89 respectively). For the control group significant pain reduction was only found in SLS_S (d = 0.56). No significant between-group differences were observed.

Conclusions: The pain reduction induced by LLRT-BFR could indicate this intervention as a preconditioning process prior to the rehabilitation of AKP.