Unilateral Hip Extension

During the hip extension, you push your glutes upward to bring your thighs and torso into one line. The glutes and hamstrings (except the outer head of the biceps femoris) are primarily responsible for this action. Other muscles in the abdomen and along the spine mainly provide stabilization. The quadriceps also contribute during the active movement.

Unilateral hip extension execution

1
Lie on your back with your feet flat on the floor. Your knees should form an angle of approximately 45 degrees. Place your arms alongside your torso with your palms on the floor.
2
Now extend one leg. Your thighs remain at the same height. This is your starting position.
3
Drive your pelvis upward from your planted leg until your thighs and torso are in one line.
4
Lower yourself back down until your glutes almost touch the floor.
5
Repeat.

Unilateral hip extension

Muscles involved:

Legs:

Hamstrings
Quadriceps (vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris)
Sartorius

Glutes:

Gluteus maximus, medius, and minimus

Pelvis:

Iliacus (hip flexor)
Psoas major (hip flexor)

Calves:

Gastrocnemius
Soleus

Abdomen:

Rectus abdominis (straight abdominal muscle)
External oblique (external oblique abdominal muscle)
Internal oblique (internal oblique abdominal muscle)
Transversus abdominis (transverse abdominal muscle, 'corset muscle')

(Lower) back and spine:

Erector spinae
Lumbar multifidus
Quadratus lumborum

Unilateral hip extension technique

Performing the exercise unilaterally makes it more difficult because the muscles in the planted leg bear the full load (with regard to the active execution). The rectus femoris (in the quadriceps) is also under continuous tension to hold the extended leg up from the hip. Together with the other quadriceps muscles, it also activates to keep this leg extended.