Proper extensibility of which of these global core muscles is important prior to performing the medicine ball pullover throw?

The proper extensibility of the latissimus dorsi is essential prior to performing the medicine ball pullover throw because this muscle significantly contributes to the movement mechanics involved in this exercise. The latissimus dorsi is responsible for shoulder extension, adduction, and internal rotation, which are critical during the pullover action.

As the exercise requires raising the medicine ball overhead and then extending through the shoulders, having adequate flexibility in the latissimus dorsi ensures a more effective range of motion and effective force production. If this muscle is tight or lacks extensibility, it can limit the movement, impair performance, and increase the risk of injury due to compensatory patterns.

While the other muscles listed play unique roles in core stabilization and torso movement, the latissimus dorsi's involvement in the overhead mechanics of the pullover throw makes its extensibility particularly important for executing the exercise safely and effectively.