- Throwing a baseball overhead
- Muscle 1: Deltoid
- Action: Lateral fibers abduct at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint
- Innervation: Axillary Nerve
- Muscle 2: Latissimus Dorsi
- Action: Extends, adducts, and medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly. RMA: elevates vertebral column and torso
- Innervation: Thoracodorsal nerve
2. Kicking a ball
- Muscle 1: Quadriceps femoris muscle group
- Action: All four heads extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint
- Innervation: Femoral Nerve
- Muscle 2: Hamstrings muscle group (specifically biceps femoris)
- Action: Flexes leg at knee joint and extends thigh at hip joint
- Innervation: Tibial and Fibular nerves from sciatic nerve
3. Doing sit-ups
- Muscle 1: External obliques
- Action: Bilaterally, compress abdomen and flex vertebral column; unilaterally, laterally flex vertebral column, and rotate vertebral columm
- Innervation: Thoracic Spinal Nerves (T7-T12) and the Iliohypogastric nerve
- Muscle 2: Rectus abdominis
- Action: Flexes vertebral column, and compresses abdomen to aid in defacation, urination, forced exhalation, and childbirth. RMA: Flexes pelvis on the vertebral column
- Innervation: Thoracic Spinal Curves (T7-T12)
4. Breathing
- Muscle 1: Diaphragm
- Action: Its contraction causes it to flatten and increase vertical dimension of thoracic cavity; its relaxation causes it to move superiorly and decreases vertical dimension of thoracic cavity
- Innervation: Phrenic Nerve (contains axons from cervical spinal nerves (C3-C5))
- Muscle 2: External intercostals
- Action: Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity; relaxation depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity
- Innervation: Thoracic spinal nerves T2-T12
Reference:
Tortora, G. J., & Derrickson, B. H. (2017). Tortora’s Principles of Anatomy & Physiology. Wiley.