Throwing a baseball overhead
Pectoralis major
Action: Adducts and medially rotates arm at shoulder joint; clavicular head flexes arm; sternocostal head extends flexed arm to side of trunk
Innervation: Medial and lateral pectoral nerves
Supraspinatus
Action: Assists deltoid muscle in abducting arm at shoulder joint
Innervation: Suprascapular nerve
Kicking a ball
Rectus femoris
Action: Extend leg at knee joint, flexes thigh at hip joint
Innervation: Femoral nerve
Vastus medialis
Action: Extend leg at knee joint
Innervation: Femoral nerve
Doing sit-ups
Rectus abdominis
Action: Flexes vertebral column, especially lumbar portion, and compresses abdomen; flexes pelvis on the vertebral column
Innervation: Thoracic spinal nerves T7–T12.
Transversus abdominis
Action: Compresses abdomen
Innervation: Thoracic spinal nerves T8–T12, iliohypogastric nerve, and ilioinguinal nerve
Breathing
Diaphragm
Action: Flatten and increase vertical dimension of thoracic cavity, resulting in inhalation; relaxation of diaphragm causes it to move superiorly and decreases vertical dimension of thoracic cavity, resulting in exhalation
Innervation: Phrenic nerve (C3–C5)
Internal intercostal muscles
Action: Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation
Innervation: Thoracic spinal nerves T2–T12
Reference: Tortora, G. J., & Derrickson, B. (2017). Principles of anatomy & physiology. Fifteenth edition; Wiley Loose-Leaf Print Companion. Hoboken, New Jersey, John Wiley & Sons, Inc.