Lecture 2: Hip pt.2

How much hip flexion is needed for normal gait?

30°

How much hip extension is needed for normal gait?

10°

How much ABDuction, ADDuction, Internal and External Rotation is needed for normal gait?

5°

In an erect posture during a closed chain movement, where is the head and feet positioned?

• head it maintained vertically over the base of support (BOS)

• feet are fixed to the ground

In a closed chain response, what happens when the pelvis anteriorly tilts?

the head and neck displace anteriorly

When the head and neck move forward due to an anterior pelvic tilt, what must happen to keep the head over the BOS?

if the tilt is extreme, there will also be thoracic kyphosis and cervical lordosis

Why is it important to keep the head vertically over the base of support in a closed chain position?

to maintain balance and postural stability

In an open chain response, how does the head and trunk move in relation to the pelvis?

the head and trunk follow the motion of the pelvis?

What happens when the femur, pelvis, and spine move together in an open chain motion?

they allow for a larger range of motion (ROM) than would be possible at a single joint

When you flex your hips while keeping your low back straight, what happens and what occurs when you allow trunk flexion?

• when keeping the back straight, there isn’t much hip flexion occurring

• when you allow trunk flexion, the pelvis anteriorly to contribute more ROM of hip flexion

What type of pelvic tilt occurs during trunk flexion in open chain movement?

anterior pelvic tilt

What occurs at the pelvis and spine when doing ABD SLR past 45°?

lateral flexion of the pelvis and lumbar spine

In a bilateral stance (sagittal plane), where is the center of gravity (COG) in relation to the hip joint?

posterior to the hip joint

In a bilateral stance with the pelvis in neutral, is muscle activation required to maintain posture at the hip?

nope, no muscles are required

What ligament counteracts gravity’s extensor moment during neutral bilateral stance?

iliofemoral ligament

When the pelvis tilts anteriorly in a bilateral stance, which muscles counteract gravity?

gluteus maximus and hamstrings

When the pelvis tilts posteriorly in a bilateral stance, which muscles counteract gravity?

the abdominals

In bilateral stance (frontal plane), how is the weight of the HAT (head, arms, trunk) distributed?

each femoral head bears ½ the weight of the HAT

In normal bilateral stance (frontal place), how much muscle activity is required to maintain a neutral position?

little muscle activity is needed because the forces on both hips cancel each other out

What happens if the pelvis shifts to the right during bilateral stance?

the right hip adducts and the left hip abducts

In response to a right pelvis shift, which muscles work together to bring the pelvis back to neutral?

right hip abductors and left hip adductors

What is the Trendelenburg sign?

a clinical sign where the pelvis drops on the opposite side of weak abductors during single-leg stance, even with attempts to compensate

If the right hip abductors are weak, which side of the pelvis will drop during stance on the right leg?

left side will drop

Is the Trendelenburg sign always caused by muscle weakness?

No, it can also be caused by pain or hip joint pathology like severe osteoarthritis (OA)

Why might someone with severe OA show a Trendelenburg sign even without muscle weakness?

to avoid strong glute med contraction, which would increase compressive forces and hip pain

What is Gluteus Medius Gait?

a gait pattern where the side bends toward the stance leg to help keep the pelvis level

Why does someone use Gluteus Medius Gait?

to compensate for weak hip abductors and reduce the load on the gluteus medius by shifting the center of gravity

In Gluteus Medius or Antalgic Gait, why does the person lean toward the stance leg?

to shift the line of gravity closer to the supporting hip joint

What effect does shifting the line of gravity have on the moment arm (MA) of the HAT (head, arms, trunk) in a Glute Med or Antalgic gait?

it reduces the moment arm of the HAT

Why is it helpful to reduce the moment arm of the HAT in the Glute med or Antalgic gait?

it reduces the force demand on the gluteus medius, making walking less painful or easier

If a patient has left hip pain or weakness, what does using a cane on the left (ipsilateral) side do?

decreases weight-bearing forces through the involved hip by transferring weight to the cane

If a patient has left hip pain, how does using a cane on the right (contralateral) side help?

it decreases weight-bearing forces through the left hip by acting as an additional limb in contact with the ground

What mechanical function does a contralateral cane provide during gait?

it assists with weightbearing, reduces hip joint compression and helps stabilize the pelvis during single-leg stance on the involved side

Why is contralateral cane use more commonly recommended in clinical practice?

it provide better mechanical advantage by counteracting the torque produced by the body’s weight on the painful or weak hip

If you hip is painful or weak, should you carry loads on the ipsilateral or contralateral side?

you should carry loads on the ipsilateral side

What is the primary function of the iliopsoas during hip movement?

contributes the most during open chain hip flexion

What happens when the femur is fixed and the iliopsoas contracts?

causes trunk flexion

What spinal movement may accompany trunk flexion by the iliopsoas when the femur is fixed?

hyperextension of the lumbar spine

When doing a sit up, the first 30-45° (crunch) of it is done by which muscle?

abdominals

After the first 30-45° of a sit up, what muscle is performing the rest of the motion?

iliopsoas

What does the rectus femoris do during open chain movement?

flexes the hip and extends the knee

What is the role of the rectus femoris when the femur is fixed?

contributes to anterior pelvic tilt

What is the role of the hamstrings during walking on level surfaces?

assist with hip extension

What do the hamstrings do in closed chain when the femur is fixed?

cause a posterior pelvic tilt

What is the primary role of hip abductors during single limb stance?

to prevent the pelvis from dropping on the unsupported side

Why are hip abductors important in gait and balance?

they provide lateral stabilization of the hip joint and pelvis

In which activities are the hip adductors especially important in?

walking, running, swimming, soccer, and similar dynamic movements

What happens functionally if there’s a 70% decrease in hip adductor strength?

there is only minimal dysfunction, showing they are not primary movers in most tasks

What is the primary role of hip adductors in movement?

act as synergists, assisting other muscles in motion and stabilization

How are the hip external rotators similar to the rotator cuff in the shoulder?

both groups have deep muscles with a stabilizing function, helping to control joint movement and alignment

Why are hip external rotators good stabilizers?

their line of action is perpendicular to the femoral shaft, making them mechanically efficient stabilizers

What is a key function of hip ERs during movement preparation?

they externally rotate the hip to prepare the lower extremity for powerful movements (ex: pivoting, pushing off)

Which larger muscles assist in hip external rotation?

• superior fibers of gluteus maximus

• posterior fibers of gluteus minimus and medius

What muscles are hip internal rotators?

anterior glute medius and TFL

What is the role of the adductor muscles when the hip is flexed?

they assists with hip extension

What is the role of the adductor muscles when the hip is extended?

they act as hip flexion synergists