Amir H. BakhtiaryPhD, PT

Associate Professor

Physiotherapy DepartmentRehabilitation faculty

Semnan University of Medical Sciences

Hip Joint Kinesiology

Hip Joint Musculature

Important characters of Hip Joint MusclesFive important point to consider1) Best position for muscle work is in the middle length or a

little bit stretch of optimum length-tension position.

2) Two Joint Muscles could produce extreme force if do NOT work on both Joints simultaneously

3) Best Tension is provided during eccentric, then isometric and finally concentric contractions

4) Muscles are responsible to move 2/3 of HAT Weight and then 1/3 of lower limb Weight (wide attachment on trunk)

5) The function of hip joint muscles is dependent on1) Joint position

2) Possible joint movement in proximal and distal segments

Describe the action of Flexor Muscles during OKC and CKC• In Open Chain

• Move forward the lower limb

• In closed Chain• Resist against Extension force which act on the WB leg

• The action line of 9 Hip muscles are front of the hip joint, but there are only four main flexor:• Iliopsoas• Rectus Femoris• Tensor Facia Lata• Sartorious

Iliopsoas Muscles

Some facts about Iliopsoas muscle

• Its connection on the vertebral causes 1) Ant Tilt and 2) forward tension on the lumbar

• In closed chain, (upright standing position), is responsible for lumbar lordosis increase to compensate Ant Tilt of Pelvic

• Its action is necessary for hip flexion during the sitting position (above 90 degree)

• Its unilateral activity cause Lumbar Lateral Flexion• Its bilateral activity cause lumbar flexion• Its line of action create shear stress on the lumbar

vertebrate

Some facts about Rectus Femoris

• Only part of Quadriceps which is two joints• Hip flexor and Knee Extensor• Knee position affect its activity• Simultaneous two joint activity cause insufficient• Knee flexion may improve its activity

Sartorius andTensor Fascia Lata Muscle

Some facts about Sartorius muscle• Strip shape• Flex, Abd, Lat Rot on Hip Joint• Flex and Med Rot on Knee joint• Important activity on simultaneously flexion in knee

and Hip joints• Its small cross section state its inability to provide

strong force

Some facts about TFL muscles• Its fibers connect to the ITB at the upper ¼ of thigh

• The tension of ITB come from TFL and GM• It pass behind the lateral side of knee cause Ext and lat

Rot of knee

• Flex, Abd, Med Rot Of Hip• Increase the tension of ITB• Release the tensile stress due to the WB on the

lateral side of femur shaft• Activation of osteoblast

snapping hip syndrome

Movement of the IT band anteriorly and posteriorly over the greater trochanter during functional activities has been implicated in “snapping hip syndrome” which is an inflammation of the trochanteric bursa

TFL and ITB

Illitobial Band Stretch

What is the Secondary flexor muscles• The secondary flexor muscles Included

• Pectineus• Add Long• Add Magnus• Gracilis

• Is two joint muscles (hip and knee flexor)• It may act in just one Joint

• These are Adductor muscles• Their flexion activity depend on their position

related to the femur (only up to 40° -50° of hip flexion)• If the femur places in a higher position their activity

changes to extension of Hip

Pectineus muscle

Adductor Muscles

Hip Adductor Muscles • Incuded:

• Pectineus• Add Mag• Add Brev• Add Long• Gracilis

• %22.5 of thigh muscles• Their important action is adjustment of pelvic by synergist activity of

Abductor muscle (create a balanced position for Pelvic) especially in unilateral standing

• In bilateral Standing, side to side stability of Pelvic, provided by co-activation of Abd and Add

• The adductors are also capable of generating a maximum isometric torque greater than that of the abductors

Some facts about Gluteus Maximus• Main extensors

• Helped by − posterior fiber of G Med, − upper Fiber of Add Mag and − Piriformis

• Upper fiber correct the TFL Tension on ITB• Its MA is bigger than Hamstrings• Best Optimum length-tension is in 70° Flexion• Work as Lat Rot, but change to Med Rot at hip flex

Gluteus Maximus

Other Hip Extensors• Two Joints muscles

• Biceps Femoris (long head)• Flexor and lat rot of Knee

• Semitendinosos and Semimembranosos• Flexor and Medial Rot of Knee

• These muscles work in all situation• Load and Unload

• Maximum MA in 35° hip flexion• However, their MA is always less than GM

• Their function depends on the knee position• %30 increase in Knee Ext

Balance between Flex/Ext muscles• Pelvic is like a pulley

• Flex muscles pull down on it from the front• Ext muscles pull down on it from the back

• Ideally a balance between two muscles is needed• Otherwise faulty posture will be appear such

as• Swayback posture• Flat back posture

Hip Abductors• Main included:

• Gluteus Med and • Gluteus Min

• Accessory Hip Abductors muscles included: • Upper part of Gluteus Max and • Sartorius and • TFL (Just during its flexion activity)

• Gluteus Minimus• Deep to the G Med• Work with G Med to

• Abd Hip• Stabilize the hip during unilateral standing• Prevent dropping of pelvic

• Best function in Neutral position or a few Hip Add• Loss their efficiency to 25% in Hip Abduction

Hip Abductors

Hip Abductors• Gluteus Medius

• Deep to G Max• Ant part cause Hip Flex and Med Rot• Med Part cause Hip Abd• Post Part cause Hip Ext and Lat Rot• In hip flexion, all portions medially rotate the hip.• All portions of the muscle abduct, regardless of hip joint

position

• Trochantric Burse separate it from great trochanter• It may origin of pain during inflammation

Hip Abductor • Gluteus Minimus

• is consistently an Hip abductor and flexor of the hip,

• its rotator function dependent on hip position• Because of its attachment to the joint capsule

• Retracts the capsule during hip abduction to prevent entrapment or

• Tightens the capsule to add to the gluteus minimus’s primary function of stabilizing the femoral head in the acetabulum

Abductor muscles• Activity of gluteus Min and Med muscles together

• to either abduct the femur (distal level free) or, • to stabilize the pelvis (and superimposed HAT) in

unilateral stance against the effects of gravity.

• They physiologically work most effectively in a neutral or slightly adducted hip (slightly lengthened abductors). • Isometric abduction torque in the neutral hip position is

82% greater than abduction torque when the hip is in 25 of abduction (shortened abductors)

Hip Abductor Weakness

a) Normal Gaitb) Trendelenburg Gait

Abductor muscles• Lateral Hip Pain Syndrome

• Seen among both the elderly and athletes• the bursae around the greater trochanter are commonly

involved• Included

• 1) the subgluteus minimus bursa, − Serve to reduce friction between gluteus Min and Ant Facet

• 2) the subgluteus medius bursa, − Serve to reduce friction between gluteus Med and Lat Facet

• 3) the large trochanteric bursa− serves to reduce friction between the posterior facet and the overlying

gluteus maximus, as well as between the IT band and the trochanter.

Hip Lateral Rotators Muscles• Main

• Obterators (Int & Ext)• Gemelus (Sup & Inf)• Quadratus Femoris• Piriformis

• Accessory• Post part of G Med & G Min• Upper part of G Max

Lateral Rotators

Some facts about Hip Lateral rotators

• Attach to femur in vertical direction• Press the head of femur to acetabulum

• Their action line is parallel to the neck of femur• They are ideal to stabilize head and neck of femur

• Their efficiency for Lat Rot reduce by hip flexion

Some Facts about Hip Medial Rotators

• There is no Special med rotator muscles• Every muscles that its line of action is in front of

joint work as Med Rot in some ROM • More important muscles in this part are

• G Med and• TFL

• The Medial Rotator Torque increases by hip flexion (3 times more than Lat Rot)• Lat rotator torque decrease by hip flexion

Hip Joint Forces and Muscle

Function in Stance