Which muscle will extend and adduct the arm for swimming or climbing a rope?

The latissimus dorsi muscle is primarily responsible for extending and adducting the arm during activities such as swimming and climbing a rope. This large muscle, located in the back, helps pull the arms down and towards the body, providing the necessary power and movement for these actions. Additionally, the teres major and the pectoralis major can assist in these motions, but the latissimus dorsi is the key muscle involved.