In the Single-leg Squat assessment, "inward trunk rotation" is attributed to overactivity of which muscle?

In the Single-leg Squat assessment, inward trunk rotation indicates that the external oblique muscle on the opposite side of the stance leg may be overactive. This muscle works to stabilize the pelvis and spine during movements that require balance and control, such as single-leg squats.

When an individual performs a squat on one leg, proper movement mechanics require the trunk to remain relatively neutral and aligned. If there is excessive inward rotation of the trunk toward the stance leg, it suggests that the external oblique on the opposite side is excessively activating to counterbalance the movement. This overactivity can lead to compensatory patterns and imbalances, negatively affecting overall movement quality.

The other muscular choices do not exhibit the same role in this context. For instance, the rectus abdominis primarily supports flexion of the trunk, but does not contribute directly to the rotational mechanics observed in this assessment. The internal oblique indeed plays a role in trunk rotation, but it is mainly involved in rotation toward its own side, not the opposite side. Lastly, the transverse abdominis functions mainly to stabilize the core and does not directly contribute to the rotation observed in this scenario. Therefore, the overactivity of the external oblique on the opposite side of the stance leg is