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Movement
Intermediate
8 min read
Kinetic atlas

Hip hinge

The hip hinge concentrates the movement at the hip: the pelvis tilts over the femoral heads, the torso leans forward, and the knees stay only slightly bent. This page describes its phases, its joints, its muscles and the confusions that surround it.
Glutes and the hip hinge
Bracing
Current phase

Bracing

before the descent
The trunk muscles contract together to stiffen the spine, the shoulder blades settle, and the weight is spread across the whole foot.
Put it into practice in Shapier
Find in Shapier the Romanian deadlift page, the exercise that most directly applies the hinge distribution, to place it within a session.
Train the hinge with the Romanian deadlift
Muscle roles in the hip hinge
Prime movers
Gluteus maximus, hamstrings, adductor magnus · Extend the hip on the way up and slow its flexion on the way down.
Synergists
Erector spinae, latissimus dorsi, gluteus medius · Maintain the alignment of the trunk and the pelvis while the hip moves.
Stabilisers
Abdominal wall, quadratus lumborum, deep hip rotators · Stiffen the trunk and control unwanted rotation in the other planes.

What the hip hinge is for

The hip hinge is the movement in which the torso leans forward while the pelvis tilts over the femoral heads and the hips travel backwards, the knees bending only slightly. Bending down to pick up a heavy object, lifting a bag off the floor, straightening up after leaning over a worktop: all these actions rely on this organisation.
What defines it is not the exercise used but how the movement is shared out. In a squat, the descent is divided between the hip, the knee and the ankle. In a hinge, most of the range is produced at the hip, while the lumbar spine and the knees keep a relatively constant position (neumann2016, schoenfeld2010squat).
Neutral spine
A zone of vertebral position lying between the ends of the available range, in which the spine is neither strongly flexed nor strongly extended. It is not a single posture measurable to the degree, but an interval specific to each person.
neutral spinal position · neutral zone

The phases of the movement

The phases serve to locate where the mechanical demand sits. They describe here a hinge performed at a controlled speed, with a load held in front of the body.

The hip hinge, phase by phase

  • 1
    Bracing
    before the descent
    The trunk muscles contract together to stiffen the spine, the shoulder blades settle, and the weight is spread across the whole foot.
  • 2
    Eccentric phase
    torso leaning
    The pelvis tilts forward over the femoral heads and the hips travel backwards. The hip extensors lengthen while producing force: they slow the descent.
  • 3
    Transition
    torso at its lowest
    The movement reverses at the point where the horizontal distance between the load and the hip is greatest, and therefore where the demand on the hip extensors is highest.
  • 4
    Concentric phase
    standing back up
    The hip extensors shorten and the pelvis returns underneath the trunk. The forward lean of the torso decreases as the hip extends.
  • 5
    End of extension
    standing position
    The hip completes its extension without the lumbar spine continuing the movement through additional extension.

Joints and planes of movement

The movement takes place essentially in the sagittal plane, the one that separates the body into a right half and a left half.
  • Hip: this is the driving joint. The femoral head turns in the acetabulum while the pelvis
tilts around it. The available range of hip flexion determines how far the torso can lean before the pelvis takes the lumbar spine with it (standring2020).
  • Lumbar and thoracic spine: they do not produce the movement, they support it. Their role is
to transmit the load of the upper body down to the pelvis.
  • Knee: it stays in a slight and roughly constant flexion. It is not locked in full extension,
but neither does it supply the main range.
  • Shoulder girdle: when the load is held at arm's length, the shoulder blades and the
latissimus dorsi take part in bracing the whole system, the latissimus dorsi attaching to the thoracolumbar fascia (standring2020).

Who does the work

Muscle roles in the hip hinge

Role
Main structures
What they do
Prime movers
Gluteus maximus, hamstrings, adductor magnus
Extend the hip on the way up and slow its flexion on the way down.
Synergists
Erector spinae, latissimus dorsi, gluteus medius
Maintain the alignment of the trunk and the pelvis while the hip moves.
Stabilisers
Abdominal wall, quadratus lumborum, deep hip rotators
Stiffen the trunk and control unwanted rotation in the other planes.
The difference from the squat comes down to how the hamstrings behave. Because they cross both the hip and the knee, their length varies little in a squat, where the two joints move at the same time. In a hinge, the knee stays almost fixed while the hip flexes: the hamstrings genuinely lengthen and become prime movers in their own right (neumann2016).
Certainty level · Established
The demand on the hip extensors increases with the horizontal distance separating the load from the hip joint.
This is a direct consequence of lever mechanics: the moment produced by an external force is that force multiplied by the length of the lever arm. When the torso leans, the load moves horizontally away from the hip and the moment to overcome increases, even though the mass being lifted has not changed. Work on trunk training describes, alongside this, a co-contraction strategy that increases trunk stiffness during this kind of effort; the optimal levels of stiffness remain debated and vary with the task and the person.
Neumann DA (2016) · McGill SM (2010)

Morphological and technical variations

The range of hip flexion available before the pelvis takes the spine with it depends on the depth and orientation of the acetabulum, on the angle of the femoral neck and on the extensibility of the posterior thigh muscles (standring2020). These parameters vary from one person to another, which explains why the achievable torso lean is not the same for everyone.
Technical variations shift the demand without changing the logic of the movement. Bending the knees a little more brings the hinge closer to a squat and increases the share taken by the quadriceps. Widening the stance changes the orientation of the hips. Holding the load closer to the body reduces the external lever arm, and therefore the moment at the hip, for the same mass (neumann2016).

Common misunderstandings

Caution
Three misconceptions about the hip hinge
“It is a squat with straight legs.” No: the knee is not locked, it stays slightly bent and, above all, roughly motionless. What distinguishes the two families is how the range is shared between hip and knee, not the rigidity of the leg.
“You have to feel your glutes for the movement to be correct.” Muscular sensation reports on the attention paid to an area, not on the force it produces. An absence of sensation does not prove that a muscle is not working.
“The hip hinge is a back exercise.” The erector spinae work there mainly in a holding role, while the extension comes from the hip. Describing this movement as a back movement blurs that division of labour.
One last confusion concerns the link between posture and pain. Flexion of the spine during effort is often presented as the direct cause of an injury. What work on trunk training describes is more cautious: it looks at the control and stiffness of the trunk during effort, without establishing any simple, universal relationship between an observed posture and the appearance of pain (mcgill2010).

Glutes and the hip hinge

The model shows the pelvis tilting over the femoral heads and the lengthening of the posterior thigh muscles while the torso leans. The text stays complete without the scene, which illustrates a general organisation and not the morphology of a real person.
Current step
A single pivot
The hip hinge plays out between three parts: the pelvis, the lumbar spine resting on it, and the femur articulating beneath. The only useful pivot is the hip, where the femoral head turns in the acetabulum. The lumbar spine is not built to supply the range.
Scene description
A three-dimensional diagram of the lower half of the body seen from behind, standing with the legs straight. The pelvis, both femurs, both tibias and a simplified lumbar spine — five vertebral bodies with their spinous processes — are shown in bone tones, while the feet and a reference trunk stay in a neutral paper shade. In terracotta, gluteus maximus caps the back of the pelvis, the hamstrings run down behind each thigh in two bundles — biceps femoris outside, semitendinosus inside — and two columns of erector spinae flank the spine up to the mid back. A three-second animation tips the pelvis forwards around the hips: the buttocks travel back, the trunk leans over, the knees bend only slightly and the hamstrings lengthen, before the movement returns to standing. The volumes are stylised: this is a teaching diagram, not an exact anatomical reconstruction.
Visible structures
  • Gluteus maximus
    The bulkiest muscle in the body, arising from the back of the iliac wing, the sacrum and the sacrotuberous ligament, and inserting on the gluteal tuberosity of the femur and the iliotibial tract. It extends the hip powerfully, above all at the end of the lockout.
  • Hamstrings
    Biceps femoris on the outside, semitendinosus and semimembranosus on the inside, all arising from the ischial tuberosity and inserting on the fibula and tibia. They extend the hip and flex the knee: in the hinge they lengthen while braking the descent.
  • Erector spinae
    Muscular columns — iliocostalis, longissimus and spinalis — running from the sacrum and iliac crest to the ribs and vertebrae. In the hinge they do not produce the movement: they keep the lumbar spine from rounding while the hip flexes.
  • Lumbar spine
    Five vertebrae stacked between the sacrum and the ribs, shown here as their bodies and spinous processes. A sound hinge rotates the pelvis on the hips while these five levels stay almost still relative to one another.
  • The hip joint
    The femoral head turns inside the acetabulum of the pelvis: this is the only pivot of the movement. The whole point of the hinge is to rotate the pelvis around this axis rather than to bend the back.
Guided steps
  • 1/5
    The hip hinge plays out between three parts: the pelvis, the lumbar spine resting on it, and the femur articulating beneath. The only useful pivot is the hip, where the femoral head turns in the acetabulum. The lumbar spine is not built to supply the range.
  • 2/5
    It arises behind the iliac wing, from the sacrum and the sacrotuberous ligament, and reaches the femur and the iliotibial tract. Its bulk and lever arm make it the main hip extensor, especially through the last part of standing back up.
  • 3/5
    All three set off from the ischial tuberosity and run down behind the thigh to the tibia and fibula. Because they cross both hip and knee, they lengthen further the more the pelvis tips forward with the knees nearly straight.
  • 4/5
    The pelvis rotates forwards around the hips, the buttocks travel backwards, and the knees bend only slightly. The hamstrings lengthen while braking the descent, then the glutes bring the pelvis back upright. The trunk follows the pelvis without the back changing shape.
  • 5/5
    Throughout the tip, the erector spinae work without shortening: they stop the spine from rounding. That is how a hinge is judged — the range comes from the hip, the spine keeps its shape, and force travels from the legs to the trunk without leaking.
Model licence · Z-Anatomy et BodyParts3D — CC-BY-SA 4.0
The hip hinge is best understood as the mirror image of the squat: the same family of lower-limb extension, with a different distribution between hip and knee. It also serves as the basis for the horizontal pull when that is performed with the torso leaning forward.
The pages devoted to the glutes, the hamstrings and the erector spinae detail the structures cited here.

Key sources

  • Neumann DA (2016). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation, 3rd edition. Elsevier.
  • Standring S (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd edition. Elsevier.
  • McGill SM (2010). Core training: evidence translating to better performance and injury prevention. Strength and Conditioning Journal.
  • Schoenfeld BJ (2010). Squatting kinematics and kinetics and their application to exercise performance. Journal of Strength and Conditioning Research.
Put it into practice in Shapier

Train the hinge with the Romanian deadlift

Find in Shapier the Romanian deadlift page, the exercise that most directly applies the hinge distribution, to place it within a session.
Train the hinge with the Romanian deadlift
Body Lab explains; Shapier lets you act and track.

Check my understanding

What fundamentally distinguishes a hip hinge from a squat?
Why do the hamstrings become prime movers in their own right in a hinge?
For the same mass, what increases the demand on the hip extensors?
Choose an answer

Read next

  • Squat
    The squat is a simultaneous flexion, then extension, of the hips, knees and ankles with the feet planted on the ground. This page describes its phases, the joints involved, the muscles that contribute and the most widespread misconceptions about it.
    With a 3D scene
  • Glutes
    The three gluteal muscles cover the back and the side of the pelvis. The gluteus maximus extends the hip, while the gluteus medius and minimus steady the pelvis as soon as the body is supported on one leg.
    With a 3D scene
  • Hamstrings
    The hamstrings occupy the back of the thigh. They extend the hip and flex the knee, and their length depends on the combined position of these two joints.
    With a 3D scene
  • Mechanical tension, fatigue and volume
    Should you lift heavy, train to exhaustion, or simply do a lot? This page untangles three variables that are often confused, shows how they combine over the course of a set, and states the level of evidence behind each one.
    With a 3D scene

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Trust and method

Author
equipe-editoriale-shapier
Editorial review
Thanh Chau
Scientific review
Pending
Published on
August 2, 2026
Reviewed on August 2, 2026
Next review due August 2, 2027
Limits of this page
  • The pattern described is a symmetrical hinge with the load held in front of the body; a load carried on one side only, or support on a single leg, changes how the loading is distributed in the frontal and transverse planes.
  • Segment lengths, the available range of hip flexion and the shape of the pelvis vary from one person to another: the 3D model illustrates a general organisation, not an individual morphology.
  • This page describes a movement, it judges no execution: persistent low back pain, pain that radiates, or pain accompanied by sensory disturbance is a matter for a healthcare professional.
Sources
  • Neumann DA (2016). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation, 3rd edition. Elsevier.
  • Standring S (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd edition. Elsevier.
  • McGill SM (2010). Core training: evidence translating to better performance and injury prevention. Strength and Conditioning Journal.
  • Schoenfeld BJ (2010). Squatting kinematics and kinetics and their application to exercise performance. Journal of Strength and Conditioning Research.
Educational content. Body Lab does not diagnose and does not replace professional advice.
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