biomechanics of running. Dr.dhwani.pptx

The biomechanics of running involves the study of the mechanical principles underlying running movements. It includes the analysis of the running gait cycle, which consists of the stance phase (foot contact to push-off) and the swing phase (foot lift-off to next contact). Key aspects include kinematics (joint angles and movements, stride length and frequency) and kinetics (forces involved in running, including ground reaction and muscle forces). Understanding these factors helps in improving running performance, optimizing technique, and preventing injuries.

1. BIOMECHANICS OF RUNNING Dr.Dhwani kawedia(PT)

2. Running is similar to walking in terms of locomotor activity, Running requires: 1. Greater balance (Double float period) 2. Greater m/s strength 3. Greater Joint ROM (absorb increased energy to control weight) During running gait cycle, the GRF & COP increase to 250% of body weight(double that of walking).

3. WALKING In this at least one foot remains in contact with ground. Longer stance phase Shorter swing phase Linear and angular velocity of L.L. is slower. Requires lesser ROM. RUNNING In this both feet are off the ground. Double and longer swing phase. Linear and angular velocity of L.L. is faster. Requires greater ROM.

4. Foot slightly inverted and supinated Pelvic is tilted and internally rotated Hip externally rotated and flexed. Knee flexed Stance phase

5. Stance phase: Loading/initial contact/heel strike to foot flat. 1 2 3 5 4 Progression towards heel strike : foot supinated with slight inversion (0-5) Pelvis ant. Tilt & internal rot. ( 10 degree ) Hip ext. rot. (10 deg.)& flexed (20-30 degree) Knee flex. (10 deg.) Due to lateral directed GRF,cascade of event- foot eversion,hip int.rot . & add., knee flexion(45 deg.)- helps GRF pass post to knee joint.

6. Midstance / foot flat to heel off

7. Propulsion / heel off to toe off

8. Foot: Supinate and plantar flexed Stance leg : knee flexion Lead leg: knee extension

9. The windlass mechanism comes into play, tightening the plantar fascia and helping to raise the arch of the foot. This mechanism is very important as it allows the foot to act as an efficient lever.

10. Initial contact Midstance Toe off

11. Initial swing

12. Terminal swing

13. Joint motion Initial contact to midstance Midstance to toe off Initial swing Terminal swing Hip joint 45 -20 flex. 20 flex- 5 ext 5 – 20 ext. 65 -40 flex Knee joint 20 – 40 flex 40 – 50 flex 15-5 flex (FLOAT phase: max knee flex(125 deg ) ) 130 – 20 flex (prepares for heel strike by extension 40) Ankle joint 5 PF- 10 DF 10 -20 DF 20-30 PF 0 -5 DF to 5 PF KINEMATICS

14. Hip joint

15. Knee joint

16. Ankle joint

17. Muscle activity Gluteus maximus and gluteus medius are both active at the beginning of stance phase and also at the end of swing phase. TFL is active from the beginning of stance and also the end of swing phase, it is also active between early and mid swing. Adductor magnus is active for about 25% of cycle, from late stance to early part of swing phase. Iliopsoas activity occurs during swing phase for 35 -60% of cycle. Quadriceps works in a eccentric manner for initial 10% of stance phase to control rapid knee flexion. Then in the last 20% of swing phase it works as concentric so it can extend the knee to prepare for heel strike.

18. Medial hamstring becomes active at the beginning of stance phase, they are also active throughout much of swing phase. In late swing, the hamstring act eccentrically to control knee extension and take hip into extension. Gastrocnemius is active at the beginning as well as at he last swing phase of the cycle (15%) Tibialis anterior is active through both stance and swing phase. Its activity is mainly concentric and isometric, enabling the foot to clear the support surface during the swing phase.

19. kinectics Internal forces: The imp m/s grp producing power for running comprises of hip flexors, extensors, abd , knee extensors and gastronicmeussoleus grp. During the 1 st part of stance, when the COM is behind the foot gletus max. and hams., Must extend the hip to move the body forward. Once the COM move over and past the foot, the quads extend the knee and calf m/s plantarflex the ankle to continue to propel body forward by pushing it ahead.

20. Ground reaction force Created between foot and the ground, in which the foot and ground exert equal and opposite force on each other. The direction and magnitude of GRF is determined by position and acceleration of runner’s COM. After max. velocity is reached, the COM moves backward. A forward trunk lean and pelvic tilit keep the GRF in a position to allow forward acceleration.

21. Elastic support strategy In runner’s diagonal elastic support mechanism is used. This is produced by a constant diagonal stretch and release that is enabled by body’s counter reaction. The pattern of force distribution prevents force being concentrated in one area, but allows wide distribution of force throughout body.

22. Rotation through kinetic chain The kinetic chain can be described as a series of joint movements, that make up a larger movement. Running mainly uses sagittal movements as the arms, legs move forward. There is also rotational component as the joints of the leg lock to support the body weight on each side. There is also an element of counter pelvic rotation as the chest moves forward on opposite side.

23. 5 most common injuries: PFPS ITBS syndrome Plantar fasciitis Medial tibial stress syndrome Knee meniscal injuries Most injuries are overuse rather than acute

24. Case 1 25 year old runner Anterior knee pain, difficult to pinpoint Described as achy Present with prolonged sitting Can still run but worse on hills

25. Case 1 Patellofemoral Pain Syndrome Patellar Tendionpathy

26. Case 2 35 year old male Has been doing a lot of 5k races Started getting posterior buttock and leg pain Worse on end of race with stride lengthening

27. Case 2 Hamstring Strain Very high recurrence rate- 30% +