1. Turning a door knob
- Muscle: Brachioradialis
- Action: Flexes forearm at the elbow joint, supinates and pronates forearm at radioulnar joints to neutral position
- Innervation: Radial nerve
- Muscle: Supinator
- Action: Supinates forearm at radioulnar joints
- Innervation: Deep radial nerve
- Muscle: Pronator teres
- Action: Pronates forearm at radioulnar joints and weakly flexes forearm at elbow joint
- Innervation: Median nerve
2. Throwing a baseball overhead
- Muscle: Pectoralis major
- Action: Adducts and medially rotates arm at shoulder joint, clavicular head flexes arm, and sternocostal head extends flexed arm to side of trunk
- Innervation: Medial and lateral pectoral nerves
- Muscle: Latissimus dorsi
- Action: Extends, adducts, and medially rotates arm at shoulder joint, and draws the arm inferiorly and posteriorly
- Innervation: Thoracodorsal nerve
- Muscle: Deltoid
- Action: Lateral fibers abduct arm at shoulder joint, anterior fibers flex and medially rotate the arm at shoulder joint, and posterior fibers extend and laterally rotate arm at shoulder joint
- Innervation: Axillary nerve
3. Kicking a ball
- Muscle: Rectus femoris
- Action: extend leg at knee joint, and also flexes thigh at hip joint
- Innervation: Femoral nerve
- Muscle: Biceps femoris
- Action: Flexes leg at knee joint and extends thigh at hip joint
- Innervation: Tibial and fibular nerves from sciatic nerve
- Muscle: Gluteus maximus
- Action: Extends thigh at hip joint and laterally rotates thigh, helps lock the knee in extension
- Innervation: Inferior gluteal nerve
4. Doing sit-ups
- Muscle: Rectus abdominis
- Action: Flexes the vertebral column and compresses the abdomen
- Innervation: Thoracic spinal nerves (T7–T12)
- Muscle: External oblique
- Action: Compresses the abdomen, laterally flexes and rotates the vertebral column
- Innervation: Thoracic spinal nerves (T7–T12) and the iliohypogastric nerve
- Muscle: Transversus abdominis
- Action: Compresses abdomen
- Innervation: Thoracic spinal nerves (T8–T12), iliohypogastric nerve, and ilioinguinal nerve
5. Walking
- Muscle: Soleus
- Action: Plantar flexes foot at ankle joint
- Innervation: Tibial nerve
- Muscle: Gastrocnemius
- Action: Plantar flexes foot at ankle joint and flexes leg at knee joint
- Innervation: Tibial nerve
- Muscle: Tibialis anterior
- Action: Dorsiflexes foot at ankle joint and inverts foot at intertarsal joints
- Innervation: Deep fibular (peroneal) nerve
6. Breathing
- Muscle: Diaphragm
- Action: Contracts upon inhalation, and relaxes upon exhalation
- Innervation: Phrenic nerve (C3–C5)
- Muscle: External intercostals
- Action: contract and assist in the elevation of the ribs, expand the thoracic cavity during forced inhalation
- Innervation: Thoracic spinal nerves (T2–T12)
- Muscle: Internal intercostals
- Action: Bring the ribs down, decrease the diameter of the thoracic cavity, and push air out of the lungs during forced exhalation
- Innervation: Thoracic spinal nerves (T2–T12)