Abstract
Quadriceps weakness and persistent muscle atrophy present major clinical obstacles during rehabilitation following anterior cruciate ligament reconstruction (ACLR), particularly among female athletes who exhibit high rates of arthrogenic muscle inhibition. Blood flow restriction (BFR) combined with low-load resistance training offers a potential therapeutic solution by stimulating metabolic stress while minimizing mechanical loads on the healing graft. This prospective randomized controlled trial evaluated the effects of an 8-week low-load BFR intervention (LL-BFR; 20–30% 1RM, 80% arterial occlusion pressure) compared to traditional high-load resistance training (HL-RT; 70–80% 1RM) and conventional low-load training (LL-RT; 20–30% 1RM) on quadriceps muscle hypertrophy and peak isokinetic torque in 36 female collegiate athletes post-ACLR (12–24 weeks post-surgery). B-mode ultrasonography revealed that LL-BFR yielded significant increases in rectus femoris (12.1 ± 2.3%) and vastus intermedius (11.4 ± 2.1%) muscle thickness, comparable to HL-RT (13.0 ± 2.5% and 12.2 ± 2.2%, respectively) and significantly greater than LL-RT (3.8 ± 1.2%). Furthermore, LL-BFR demonstrated marked improvements in peak isokinetic extension torque at 60°/s (28.4% increase) with lower post-exercise anterior knee pain ratings than HL-RT (VAS: 1.8 vs. 4.2, p < 0.01). These findings indicate that low-load BFR resistance training is a highly effective, joint-sparing modality for reversing quadriceps deficits and accelerating neuromuscular recovery in female athletes following ACL reconstruction.
