Abstract
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.
Key words
anterior cruciate ligament injury - quadriceps weakness - limb asymmetry - BFR exercise
