Sumo deadlift muscles worked

Every role here is for this technique: barbell from the floor, wide stance with toes turned out, hands inside the knees, back flat, to standing tall.

What muscles does the sumo deadlift work?

The prime movers of the sumo deadlift are gluteus maximus, adductor magnus, the hamstrings, the quadriceps and the erector spinae. They produce hip extension and knee extension, and hold the spine extended. The synergists are adductor longus and brevis, and gracilis. Twelve stabilizers hold joints and segments still, among them tibialis anterior, gastrocnemius and multifidus.

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Joint actions and their prime movers

The joint actions of the sumo deadlift and the prime movers that produce each
Joint action	Prime movers
Hip extension	Gluteus maximus, adductor magnus and the hamstrings
Knee extension	The quadriceps
Holding the spine extended	The erector spinae

Every muscle by role

A prime mover produces the lift’s main joint action against the load; a synergist assists that action, or adds a secondary action the lift needs; a stabilizer contracts mostly isometrically to hold a joint or a segment still. A role describes what the muscle does in the technique above, not how hard it works or how much it grows.

Prime movers 5

Prime movers in the sumo deadlift, with what each does
Muscle	What it does here
Gluteus maximus	Hip extension
Adductor magnus	Hip extension from a wide stance
Hamstrings	Hip extension
Quadriceps	Knee extension The vasti were more active in the sumo than the conventional deadlift (Escamilla et al. 2002).
Erector spinae	Keeping the spine from rounding under the bar, without changing length

Synergists 2

Synergists in the sumo deadlift, with what each does
Muscle	What it does here
Adductor longus and brevis	Bringing the thighs in as the hips extend
Gracilis	Bringing the thighs in as the hips extend

Stabilizers 12

Stabilizers in the sumo deadlift, with what each does
Muscle	What it does here
Tibialis anterior	Steadying the ankle and holding the shins More active than in the conventional deadlift (Escamilla et al. 2002).
Gastrocnemius	Steadying the ankle
Multifidus	Stiffening each lumbar segment
Rectus abdominis	Bracing the trunk against the load
External oblique	Bracing the trunk and resisting rotation
Internal oblique	Bracing the trunk and resisting rotation
Transversus abdominis	Raising abdominal pressure to stiffen the trunk
Latissimus dorsi	Keeping the bar close to the body
Upper trapezius	Holding the shoulder girdle up against the bar’s pull
Rhomboids	Holding the shoulder blades back
Wrist and finger flexors	Gripping the bar
Gluteus medius	Keeping the knees pushed out over the feet

Lowering and lifting

What the prime movers of the sumo deadlift do in each half of a rep
Phase	What the prime movers do
Lowering	The hip extensors lengthen under load while the erector spinae hold the back flat
Lifting	The hip and knee extensors shorten while the erector spinae hold

The erector spinae hold without changing length, though they are prime movers rather than stabilizers.

Where these prime movers also work

Gluteus maximus: prime mover in the back squat, front squat, leg press, conventional deadlift, Romanian deadlift, barbell hip thrust, Bulgarian split squat and walking lunge.
Adductor magnus: prime mover in the back squat, front squat, leg press, conventional deadlift, Romanian deadlift, Bulgarian split squat and walking lunge; synergist in the barbell hip thrust.
The hamstrings: prime mover in the conventional deadlift, Romanian deadlift and lying leg curl; synergist in the back squat, front squat, leg press, barbell hip thrust, Bulgarian split squat and walking lunge.
The quadriceps: prime mover in the back squat, front squat, leg press, conventional deadlift, Bulgarian split squat, walking lunge and leg extension; synergist in the barbell hip thrust and front plank.
The erector spinae: prime mover in the conventional deadlift and Romanian deadlift.

Compared with the other hinge lifts

Conventional deadlift: the same prime movers; synergists only here, adductor longus and brevis, and gracilis; synergists only in the conventional deadlift, gastrocnemius and soleus; stabilizers only here, gastrocnemius; stabilizers only in the conventional deadlift, quadratus lumborum, the middle trapezius and the lower trapezius. The quadriceps here: the vasti were more active in the sumo than the conventional deadlift (Escamilla et al. 2002). Tibialis anterior here: more active than in the conventional deadlift (Escamilla et al. 2002). Gastrocnemius in the conventional deadlift: more active than in the sumo deadlift (Escamilla et al. 2002).
Romanian deadlift: prime movers in both, the hamstrings, gluteus maximus, adductor magnus and the erector spinae; prime movers only here, the quadriceps.
Barbell hip thrust: prime movers in both, gluteus maximus; prime movers only here, adductor magnus, the hamstrings, the quadriceps and the erector spinae.

Sources

Escamilla et al. (2002), Med Sci Sports Exerc 34(4):682
NSCA, Essentials of Strength Training and Conditioning, 4th ed. (2016)

The cited studies that measured muscle activity used electromyography, and a larger signal need not mean more force or more growth (Vigotsky et al. (2018), Front Physiol 8:985). The roles draw on those studies for which muscles a lift involves and how two lifts differ, never to rank one muscle against another.

See these muscles in 3D

Visualiser · Biology Muscles Worked by Exercise 3D Explorer Choose a lift and a real body lights its prime movers, synergists and stabilisers, front and back, with the same muscles in 3D. Visualiser · Biology Muscle Origin, Insertion and Action Explorer Paint a muscle’s origin and insertion on real 3D bones, or click a bone to see what attaches to it.