Name at least two muscles that actively contracts during the following activities and name its action and innervation:
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The two muscles that actively contract when throwing a baseball overhead are the latissimus dorsi and the deltoids.
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The job of the latissimus dorsi is to extend, adduct, and medially rotate the arms at shoulder joints, and draw arms inferiorly and posteriorly. Its innervation is in the thoracodorsal nerve.
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The deltoid’s lateral fibers adduct the arms at shoulder joints, its anterior fibers flex and medially rotate the arms at shoulder joints, and the posterior fibers extend and laterally rotate the arms at shoulder joint. Its innervation is in the axillary nerve.
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The muscles quadriceps and hamstrings contribute a lot when kicking a ball.
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The quadriceps extend the leg at knee joint. Its innervation is the femoral nerve.
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The hamstrings flexes the leg at knee joint and extends thigh at hip joint. Its innervation is the tibial and fibular nerves from the sciatic nerve.
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The two muscles that actively contract when doing the sit-ups are the rectus abdominis and transversus abdominis.
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The action of the rectus abdominis is to flex the vertebral column, specifically the lumbar portion. Its innervation is the thoracic spinal nerves T7-T12.
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The transversus abdominis compresses the abdomen. The innervation is the thoracic spinal nerves T8-T12, iliohypogastric nerve, and ilioinguinal nerve.
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The diaphragm and external intercostals support breathing.
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The action of the diaphragm is the contraction of it that causes the flattening and increasing of the vertical dimension of the thoracic cavity, and its innervation is in the phrenic nerve, wherein it has the axons from the cervical spinal nerves (C3-C5).
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For the external intercostals, its action is the contraction of the ribs which causes it to elevate. Also, it increases the anteroposterior and lateral dimension of the thoracic cavity. The innervation is in the thoracic spinal nerves T2-T12.
Reference:
Tortora, G. J., Derrickson, B., Burkett, B., Peoples, G., Dye, D., Cooke, J., Diversi, T., McKean, M., Samalia, L., & Mellifont, R. (2022). Principles of anatomy and physiology (3rd ed.). John Wiley & Sons Australia, Ltd.