RESUMO
Quadriceps atrophy and weakness can persist for years after anterior cruciate ligament reconstruction (ACLR). We evaluated the effectiveness of a home-based blood flow restriction (BFR) exercise program to increase quadriceps size and strength several years after ACLR. Nine adults with ACLR (5±2 yrs post-surgery, ≤90% symmetry in quadriceps size and strength) and nine uninjured controls volunteered. ACLR participants exercised at home for 25 min, 5×/wk for 4 wks (single-leg knee extension, bodyweight half-squats, walking). Blood flow in only the involved leg was restricted using a thigh cuff inflated to 50% of limb occlusion pressure. Rectus femoris and vastus lateralis thickness and knee extensor strength were measured before and after training. Baseline and post-training symmetry (involved leg/uninvolved leg) indices were compared to uninjured controls. Rectus femoris and vastus lateralis thickness and knee extensor strength in the involved leg increased by 11±5%, 10±6%, and 20±14%, respectively (all P<0.01). Compared to baseline, post-training knee extensor strength symmetry increased from 88±4 to 99±5% (P<0.01) and did not differ from uninjured controls (99±5%, P=0.95). Implementation of BFR exercise at home was feasible, safe and effective. Results extend upon early post-operative application of BFR exercise for ACLR recovery and demonstrate that BFR can improve quadriceps function long after ACLR.