Final answer:
The correct exercise for improving shoulder horizontal abduction is the Cable Crossover. This activity targets the posterior deltoid, infraspinatus, and teres minor during the movement of pulling the arms back out.
Step-by-step explanation:
The activity used as a functional exercise for improving shoulder horizontal abduction is C. Cable Crossover. Horizontal abduction of the shoulder involves moving the arms away from the midline of the body in a horizontal plane. This movement specifically targets muscles such as the posterior deltoid, infraspinatus, and teres minor, which are part of the scapular muscles responsible for the lateral rotation and extension of the arm.
The cable crossover exercise requires an individual to pull cables from both sides toward the center and then back out, which involves horizontal abduction. On the other hand, front raises (A) and lateral raises (B) target different aspects of the deltoid muscles, primarily involving shoulder flexion and abduction respectively, and bent-over rows (D) are more focused on horizontal adduction and extension of the shoulder, working the latissimus dorsi and other back muscles.