Barbell Sumo Deadlift

The deadlift is also known as the king of all exercises. Looking at the list of muscles involved above, you can infer why.

The calf muscles bring the lower legs, which extend forward, back into alignment above the ankles when you stand up and also provide stabilization throughout the entire movement.
The quadriceps work hard to extend the knees.
The hamstrings and glutes work to bring the upper body upright by aligning the thighs and back.
The erector spinae, which runs along the spine, helps straighten the back.
The abdominal muscles primarily provide stabilization (the rectus abdominis acting as an antagonist to the erector spinae and the obliques braking lateral tilting)
The muscles in the upper back and neck engage to pull the shoulders up and back.

The sumo deadlift is a variation in which the legs are positioned wider apart and the feet point slightly outward. The hands are positioned on the inside of the legs. This allows the knees to bend further while the back remains straighter. This places a greater load on the quadriceps and the adductors on the inside of the thigh, while placing less load on the lower back.

Barbell sumo deadlift execution

1
Drive your heels forcefully into the floor to bring yourself upward. Keep the barbell as close to your shins as possible.
2
Continue until your legs are almost straight and your back is upright with its natural curve. Just as when you normally stand upright. Do not pull it back too far and therefore do not create an exaggerated curve in your back at the end of the movement (no hyperextension).
3
Push your glutes slightly backward to make room for the bar and bend your knees in a controlled manner.
4
Repeat.

Barbell sumo deadlift

Muscles involved:

Legs:

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

Glutes:

Gluteus maximus, medius and minimus

Pelvis:

Iliacus (hip flexor)
Psoas major (hip flexor)

Calves:

Gastrocnemius
Soleus

Abdomen:

Rectus abdominis (rectus abdominis muscle)
Obliquus externus abdominis (external oblique muscle)
Obliquus internus abdominis (internal oblique muscle)
Transversus abdominis (transverse abdominal muscle, ‘corset muscle’)

(Lower) back and spine:

Erector spinae
Lumbar multifidus
Quadratus lumborum

Back and neck:

Trapezius
Rhomboids
Levator scapulae

Barbell sumo deadlift setup

Make sure any plates on the bar are properly secured.
Stand directly in front of the barbell with your feet at least wider than shoulder-width apart (see below).
Bend your knees and grip the barbell with one to two fists’ distance between your hands. Ensure that your hands are evenly spaced by checking the markings on the bar. This can make a significant difference to the balance of the barbell, especially in the sumo deadlift. For a good grip, it may be helpful to hold the bar with one hand with the palm facing forward and the other hand with the palm facing backward. Wrist straps may be advisable with heavier weights.
Make sure your knees point in the same direction as your feet, at an angle of approximately 30 degrees outward.
Maintain the natural curvature of your back and try to keep your back (almost) straight up.
Brace your abdomen and glutes like a natural weightlifting belt to protect your back.

Barbell sumo deadlift technique

There are many variations of the deadlift. There is also much debate about the ‘standard’ execution. For example, about how wide the feet should be positioned, whether you push from the heels or the balls of the feet, and about bracing the abdomen. The ‘optimal’ execution can also depend on your personal proportions, mobility and other physical characteristics. This also applies to the exact width of your stance and the exact angle of your feet in the sumo squat.

In any case, do not grip the barbell too narrowly to prevent the forearms from constantly having to work to keep the barbell balanced.