hip muscle function and stability

What are the primary hip flexors

illiopsoas

sartorius

TFL

rectus femoris

adductor longus

pectineus

adductor brevis

what is the force couple for anterior pelvic tilt

hip flexors and lumbar extensors

Why does hip flexion often occur simultaneously occur with knee flexion

active insufficiency of rectus femoris

passive insufficiency of hamstrings

What will happen if there is weakness of the rectus abdominus 

you will go into an anterior pelvic tilt 

What are the primary hip adductors

pectineus

adductor brevis

adductor longus

adductor magnus

gracilis

What planes can the hip adductor muscles work to produce torque in

adduction

flexion/extension

IR

Forceful adduction in a closed chain position 

requires an eccentric contraction of the glute medius on the side of the support leg such as kicking a soccer ball

adductor magnus

ALWAYS an extender

when the hip is in full extension

anterior to axis

when the hip is in full flexion

posterior to axis 

Where do most adductors attach to?

the posterior aspect of the femur at the linea aspera

what are the hip internal rotators

there are no primary muscles for this action

secondary:

• glut mein

• glut med

• TFL

• adductor longus

• adductor brevis

• pectineus

what position of the hip is the torque potential of hip internal rotators increased significantly?

90 degrees in flexion 

this caused the line of pull to go from almost completely parallel to almost completely perpendicular 

What muscles increase torque capacity by 8x

glut med and min

What are the primary hip extensors

glut max

hamstrings

posterior head of adductor magnus

posterior fibers of glut med

anterior head of adductor magnus

hip adductors flexed below 70 degrees

What is the force couple for a posterior pelvic tilt 

hip extensors and abdominal muscles 

what are the primary hip abductors

glut med

glut min

TFL

If there is a weakness of the hip abductors what will this cause

a pelvic drop on the opposite side/leg

uncompensated trendelenburg sign

pelvis will drop, increasing stress on the illiotibial band

• glut med is disfunctional

compensated trendelenburg

person leans trunk over weight- bearing side

this reduces stress on the joint 

• glut med is dysfunctional

when is the greatest amount of torque produced for the hip abductors

when the muscle is elongated (slightly adducted or in neutral)

this increased the passive tension in the stretched IT band

What are the primary hip external rotators

piriformis

obturator externus

gemellus superior and inferior

qudratus femoris

glut max

posterior fibers of glut med

Contraction of the external rotators in a closed chain position will…?

Accelerate the pelvis and lumbar spine into rotation to the opposite side

what is in the first rank order for torque production of the hip musculature

hip extensors 

zone of weakness

are in the femoral neck in which the trabecular networks are relatively thin and do not cross each other

where is the greatest resistance to stress and strain placed on the hip

areas where the trabecular systems cross each other

both in the pelvis and hip joint itself