1. Throwing baseball overhead
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Muscle: Pectoralis Major
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Action: as a whole adducts and medially rotates arm at shoulder joint; clavicular head flexes arm and sternocostal head extends flexed arm to side of trunk
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Innervation: medial and lateral pectoral nerves
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Muscle: Deltoid
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Action: lateral fibers abduct arm at shoulder joint; anterior fibers flex and medial rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint
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Innervation: axillary nerve
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2. Kicking a Ball
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Muscle: Rectus Femoris
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Action: all four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint
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Innervation: femoral nerve
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Muscle: Biceps femoris
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Action: flexes leg at knee joint and extends thigh at hip joint
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Innervation: tibial and fibular nerves from sciatic nerve
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3. Doing Sit ups
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Muscle: Rectus abdominis
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Action: Flexes vertebral column, especially lumbar portion, and compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth; RMA: flexes pelvis on the vertebral column
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Innervation: Thoracic spinal nerves T7-T12
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Muscle: External obliques
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Action: Acting together (bilaterally), compress abdomen and flex vertebral column, acting singly (unilaterally) , laterally flex vertebral column, especially lumbar portion, and rotate vertebral column
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Innervation: Thoracic spinal nerves T7-T12 and iliohypogastric nerve
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4. Breathing
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Muscle: Diaphragm
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Action: contraction of diaphragm causes it to flatten and increases 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
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Innervation: phrenic nerve, which contains axons from cervical spinal nerves C3-C5
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Muscle: External intercostal
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Action: Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity, resulting in inhalation; relaxation depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity, resulting in exhalation.
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Innervation: Thoracic spinal nerves T2–T12.
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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.