Turning a door knob
Brachioradialis
- Action: The brachioradialis flexes the forearm at the elbow. It also supinates and pronates the forearm at the radioulnar joints.
- Innervation: Radial nerve
Pronator teres and quadratus
- Action: The pronator pronates the forearm at radioulnar joints and weakly flexes the forearm at the elbow joint.
- Innervation: median nerve
Supinator
- Action: This supinates the forearm at the radioulnar joints.
- Innervation: Deep radial nerve
Throwing a baseball overhead
Deltoid
- Action: abducts arm at the shoulder; medially rotates the arm at the shoulder
- Innervation: Axiliary nerve
Pectoralis major
- Action: adducts and meidally rotates arm at the shoulder joint; flexes arm; extends arm
- Innervation: medial and lateral pectoral nerves
Brachioradialis
- Action: flexes forearm; supinates and pronates forearm at the radioulnar joint
- Innervation: radial nerve
Kicking a ball
Quadriceps femoris (rectus femoris)
- Action: extends leg at knee joint; flexes thigh at the hip joint
- Innervation: femoral nerve
Iliopsoas
- Action: Flexes thigh at the hip joint
- Innervation: lumbar spinal nerves
Hamstrings (biceps femoris, semitendinosus, semimembranosus)
- Action: Flexes leg at the knee joint and extends thigh at the hip joint
- Innervation: Tibial nerve, fibular nerve, the sciatic nerve
Doing sit-ups
Rectus abdominis
- Action: This flexes the vertebral column as well as compresses the abdomen
- Innervation: Thoracic spinal nerves
Transverse abdominis
- Action: compresses abdomen
- Innervation: thoracic spinal nerve, iliohypogastric nerve, ilioinguinal nerve
Walking
Quadriceps femoris
- Action: the four heads extend to the knee joint, but only the rectus femoris flexes the thigh at the hip joint
- Innervation: Femoral nerve
Sartorius
- Action: weakly flexes leg at knee joint
- Innervation: Femoral nerve
Hamstrings (biceps femoris, semitendinosus, semimembranosus)
- Action: Flexes leg at knee joint and extends thigh at hip joint
- Innervation: Tibial nerve, fibular nerve, the sciatic nerve
Gluteus maximus
- Action: Extends the thigh at the hip joint and helps lock the knee in extension
- Innervation: inferior gluteal nerve
Gastrocnemius
- Action: It flexes the foot at the ankle joint and flexes the leg at the knee joint
- Innervation: Tibial nerve
Breathing
Diaphragm
- Action: Flattens and increases vertical dimension of thoracic cavity; thus, inhalation happens
- Innervation: Phrenic nerve
External intercostals
- Action: elevates ribs, and increases dimensions of thoracic cavity; this results in inhalation
- Innervation: Thoracic spinal nerves
Internal intercostals
- Action: decreases dimensions of thoracic cavity; exhalation
- Innervation: Thoracic spinal nerves