4. Amir H. Bakhtiary PhD, PT Associate Professor Physiotherapy Department Rehabilitation faculty Semnan University of Medical Sciences Hip Joint Kinesiology

5. Hip Joint Musculature

6. Important characters of Hip Joint Muscles Five important point to consider 1)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 on 1)Joint position 2)Possible joint movement in proximal and distal segments

7. 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

8. Iliopsoas Muscles

9. 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

10. 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

11. Sartorius and Tensor Fascia Lata Muscle

12. 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

13. 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

14. 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

15. TFL and ITB Illitobial Band Stretch

16. 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

17. Pectineus muscle

18. Adductor Muscles

19. 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

20. 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

21. Gluteus Maximus

22. 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

23. 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

25. 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)

26. 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

27. 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

28. 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

29. 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)

30. Hip Abductor Weakness a) Normal Gait b) Trendelenburg Gait

31. 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.

32. 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

33. Lateral Rotators

34. 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

35. 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

36. Hip Joint Forces and Muscle Function in Stance