Y-Balance Test after ACL Reconstruction: The relationship with knee and hip muscle strength, ankle dorsiflexion range of motion and postural stability.

Background: Y-Balance Test (YBT) assesses postural stability. When is applied to patients after anterior cruciate ligament reconstruction (ACLR), it is not clear which variables influence its result.

Objective: To connect YBT and postural stability, quadriceps, hamstring, and gluteus complex muscle strength, ankle dorsiflexion range of motion (ADFROM).

Study design: Cross-sectional.

Methods: Fifty-nine participants (52 males and 7 females) with ACLR ≥6 months were evaluated. YBT anterior, posterolateral, posteromedial, and composite, isokinetic peak torque of the knee, strength of the gluteal complex with Hip Stability Isometric Test, ADFROM with Weight-Bearing Lunge Test, postural stability with Stability Index of Biodex Balance System® were applied.

Results: In the ACLR limb, the multivariate regression linear models pointed out an association between the quadriceps muscle strength and ADFRM with anterior, posteromedial and composite reaches (R² = 0.30; 0.23; 0.26). Hamstring muscle strength and ADFRM with posterolateral (R² = 0.13). In the uninjured limb, overall stability index and ADFRM with anterior reach (R² = 0.25), strength of gluteal complex with posteromedial (R² = 0.31), hamstring muscle strength, Overall and lateromedial stability indexes with posterolateral (R² = 0.20), hamstring muscle strength, Overall stability index, ADFRM and strength of gluteal complex with composite (R² = 0.32).

Conclusions: The quadriceps muscle strength and ADFRM are important variables for YBT performance in the ACLR limb. In the uninjured limb, ADFROM, the strength of the gluteal complex and hamstring, overall and lateromedial stability indexes are associated with YBT performance. We question the utility of the YBT to measure postural stability given the lack of association with other postural stability measures.