Gait Analysis PDF

GAIT Academic Staff: Asst. Prof. Berrak Varhan E-mail: [email protected] Department: Physiotherapy and Rehabilitation Course: Clinical Biomechanics and Kinesiology  CONTENTS Definition of gait Phases of gait Assessment methods Pathological gait  NORMAL GAI...

GAIT Academic Staff: Asst. Prof. Berrak Varhan E-mail: [email protected] Department: Physiotherapy and Rehabilitation Course: Clinical Biomechanics and Kinesiology  CONTENTS Definition of gait Phases of gait Assessment methods Pathological gait  NORMAL GAIT Gait: It is defined as the rhythmic alternating movements of the trunk and extremities with the forward displacement of the center of gravity. From a biomechanical point of view, walking is explained as the rhythmic loss and gain of balance. 3  Gait cycle: It is the time that passes between the heel stroke of a lower limb and the subsequent heel stroke of the same lower extremity. 4  Ground Reaction Force According to Newton's third law, the weight created by the standing man on the ground responds to the force vector with a force vector of the same size and an inverse direction. This is called the ground reaction force vector (GRFV). When walking, GRFV is formed against the combination of body weight and muscle forces that provide 5 movement, and its 6  The gait period is divided into 2 main groups. 1. Stance Phase 2. Swing Phase In adults, the stance phase covers 60% of the walking period (Max 70%). The swinging phase constitutes 40%. 7  STANCE PHASE Heal strike – Heel contact Foot flat Mid-stance Heel off – Push off Toe off 8 9  [ Basma fazı ][ Salınım fazı ] Stance phase Swing phase 1- Initial contact 6- Initial swing 2- Loading response 7- Mid-swing 3- Midstance 8- Terminal swing 4- Terminal stance 5- Preswing 10 Double Support Phase 11 12  Roughly this is the phase in which both lower extremities are in contact with the ground. In this case, one lower limb is between the heel stroke and the foot flat, while the other is between the lower extremity thrust phase and toe off. The double support phase covers 25% of the walking period in the walk with normal speed. 13  During the double support phase, there is a prolongation in slow walking and a decrease in fast walking. The double support phase separates walking from running. In running, it completely disappears. 14  HEEL STRIKE İnitial contact When the heel touches the ground when stepping, the phase begins. It is 0-2% of the gait cycle. It is the beginning of the stance phase. 15  The hip is in 30° flexion, the knee is in full extension, the ankle is in a neutral position and the foot is supinated. The goal is to lower the foot to the ground so that the heel touches the ground first. When the heel first hits the ground, the torso is behind the foot. The body center of gravity is at its lowest point and at its highest speed. 16 17 Movements of the Foot in the Stance Phase in the Moving Forward of the Body (Rockers) Heel rocker When the foot touches the ground, the body begins to turn forward over the heel. During this period, the heel works as the fulcrum of a lever. The heel rocker advances the entire heel of the stepping limb. 18  Foot Flat Flat foot-loading response Shortly after the heel touches the ground, the sole of the foot also touches the ground. The walking cycle is at 2-10%, it is also the first double support phase. 19  The body weight is transferred to this foot until the other foot is lifted off the ground. The hip comes from flexion to extension, the knee is in 20° flexion, the ankle is in 10° plantar flexion. The aim is shock absorption, lowering the entire foot to the ground and assuming body weight. 20  The center of gravity of the body begins to rise. The external moments created by the ground reaction force vector are flexion in the hip and knee, and plantar flexion in the ankle. 21 22  Ankle rocker When the entire foot touches the ground, rotation ends in the heel, rotation from the ankle begins. The foot is fixed on the floor. 23  Mid-Stance Late flat foot-early heel rise-mid stance The point of gravity of the body is on the foot fixed vertically. The gait cycle is at 10 – 30%, the beginning of the single stance phase. 24  The hip and knee are in extension, and the ankle is in dorsiflexion. The leg in the swing phase passes near the standing leg. The aim is to move the trunk forward on the foot that is fixed on the ground. 25  During this period, the forward speed of the body’s center of gravity is minimized, and its height reaches the highest and outermost lateral point. The ground reaction force vector passes through the middle of the hip, behind the knee, in front of the ankle. 26 27  Differences between the foot flat and the mid-stance phase 1. Foot Flat is the contact of the sole of the foot of the moving limb with the ground. In Mid Stance, there is also contact of the sole of the foot with the ground, but in Mid Stance the weight is completely on the limb. 28 2. In Foot Flat, the knee joint is in the 15-200 position and the Mid Stance is in the 10-150 position. 3. In Foot Flat, Quadriceps, there is still eccentric type contraction, while in Mid Stance there is isotonic contraction. 29  Heel off Terminal stance-heel rise The gait cycle is 30-50%. The single stance phase ends. 30  The hip is 10° extension, the knee comes from extension to flexion, the ankle is in plantar flexion. The goal is to cut the leg off the ground. The height and sideways shift of the body center of gravity decreases, the ground reaction force vector is behind the hip, in front of the knee and ankle. 31 32  Forefoot rocker When GRFV reaches the front foot, the heel lifts off the ground, the rotation in the ankle ends, and the rotation of the front foot begins. Progress accelerates when the VAM- COG support area begins to fall in front of its center. Here the body mass is now like a passive weight at the end of a long lever arm, and there is no force to prevent it from falling until the other foot is on the ground. 33  Toe off Toe off-pre swing Detachment of fingers from the floor, gait cycle 50-60%. It is the period when the stance phase ends and the swing phase begins and also forms the second double support phase. 34  It begins when the opposite limb touches the ground and ends with the cutting of the fingers from the ground. Hip extension, knee flexion and ankle plantar flexion are increased. During this period, the body weight lifts over the limbs. 35  The goal is to prepare the leg for swing. Before the foot leaves the ground, the ground reaction force vector passes behind the knee. When the toes lift off the ground, the ground reaction force vector decreases and disappears. 36  Push off Phase The time that passes between the separation of the heel from the ground and the separation of the fingers from the ground is called the push-off phase. The heel of the fixed foot leaves the ground after the middle of the stance phase. Although the heel no longer has contact with the ground, the toes are on the ground. 37  As soon as the heel of the fixed foot leaves the ground, the body accelerates with an intense activation of the calf muscles. When the toes are completely separated from the ground and the limb enters the swing phase, the stance phase ends. 38 39 Swing Phase 40  Swing phase 1. Inıtial swing 2. Mid swing 3. Terminal swing 41  Acceleration Acceleration-initial swing The acceleration phase begins as soon as the toes leave the ground. The foot must accelerate so that the heel can touch the ground in front of the body. The gait cycle begins with 60-73% lifting of the foot from the ground; it ends when the foot reaches the level of the other limb. 42  Flexion increases in the hip and knee, and dorsiflexion occurs in the ankle. The goal is to quickly move the leg forward in the air. Knee flexion occurs with the effect of inertia. 43  Mid-swing Phase This phase begins when the foot accelerates forward while in the air. At this time, the limb should be above so that it does not touch the ground. Gait cycle 73-87% 44  The swinging leg comes to the leg in the stance phase and passes in front of it. Flexion increases in the hip and knee, and dorsiflexion is performed in the ankle. The goal is to transfer the foot without touching the ground. While hip and knee flexion is performed passively with inertia effect, ankle dorsiflexors continue to contract. 45  Deceleration deceleration-terminal swing Gait cycle 87-100% It begins when the oscillating leg passes in front of the pressing leg; it lasts until the moment when the foot touches the ground. The hip is in flexion, the knee is in extension, and the ankle is in a neutral position. 46  The goal is for the foot to prepare to step on the ground. With the full extension of the knee, the step length increases. Just before the heel touches the ground, the forward movement of the leg is braked to control the foot. This situation, which occurs after the middle acceleration phase, is the deceleration situation. 47  Determinants of Normal Gait Six movements have been identified that reduce the displacements of the body's center of gravity during walking. Thanks to these movements, called determinants, the oscillations of the body center of gravity in each plane are minimized and it is ensured that it proceeds like the movement of the wheel center, preventing sudden changes of direction. In this way, energy consumption is reduced. 48 1. Vertical displacement of the gravity center Lateral displacement of the gravity center Pelvic rotation Pelvic tilt Width of the support surface The cadence of the gait 2. Kinematic 49  1. Vertical displacement of the gravity center Sinusoidal curves have been obtained that show that the gravitational center shifts up and down rhythmically with forward displacement. The average amount of verticale displacement in an adult male is 5.08cm. is. 50  If this value rises above normal, excessive oscillations occur in the pelvis. This increases energy consumption. 51 How is this feature able to remain within the same limits? It is based entirely on structural features. The femoral shaft goes from abduction to adduction, while the tibia is vertical. This angulation creates the angle of valgite in the knee. 52  If there is no normal valgus in the knee and the legs are parallel to each other, it becomes difficult to cut the feet off the ground and pelvic elevation is seen. The total displacement of the gravity center in the vertical is limited to 5 cm due to the valgus in the knee. 53  Why does the gravity center change in the vertical direction? Between the trochanter major and the iliac crista is the gluteus medius, a hip stabilizer. When weight is placed on the limb, the gluteus medius contracts on that side and lifts the pelvis up on the opposite side. lowers the pelvis towards its side (pulls it downwards and laterally). 54 55  2. Lateral Displacement of the Center of Gravity With the transfer of weight from one lower limb to another, the pelvis and body are tilted towards the side where the weight is carried. In addition to the displacement of the center of gravity in normal gait, oscillations occur in the horizontal plane from side to side. 56  The amount of lateral displacement is also about 5 cm in adult males. Why does it occur? The gluteus medius pulls the place where it stabilizes when contracting downwards and laterally. 57  3. Pelvic Rotation When walking, the pelvis performs lateral and vertical osscillation, external rotation around the weight-bearing limb, internal rotation around the non-weight- bearing limb. Bilateral sides do not exceed 8-10º. 58 59  4. Pelvic Tilt It is the downward fall of the pelvis on the side that carries weight relative to the horizontal plane and displaces it upwards on the opposite side. The total value of the right-left is 10 degrees. The occurrence of the pelvic tilt is extremely important in the walk. 60  Thus, less energy is lost. If the pelvic tilt had not occurred, there would have been more energy consumption as the displacement of the gravitational center in the vertical would have increased. 61  5. Width of Support Surface On an imprinted surface such as powder or sand, the person is walked, and the midpoints of both heels are joined. The distance between these 2 axes gives the width of the support surface of the march. This is normally between 5-10cm. If it falls below 5 cm, adduction occurs, and if it falls above 10 cm, abduction gait occurs. 62  6. The Cadence of Gait The number of steps taken per minute determines the cadence of gait. Slow gait: If the number of steps per minute is 70 Normal gait: Walking with 90-110 steps per minute is called normal gait. Fast Gait: If the number of steps per minute is 130, it is called fast gait (the double support period is shortened). 63 7. Kinematic Parameters 64 ANKLE JOINT ANALYSES BETWEEN THE HEEL STRIKE AND THE MID STANCE PHASE 65  KINEMATIC ANALYSIS Heel strike: In a neutral position Foot Flat: At 15-degree plantar flexion Mid stance: In relative dorsiflexion of 3-5 degrees 66  Kinetic Analysis EXTERNAL FORCES INTERNAL FORCES 3 primer dorsiflexor are activated at the Heel Strike: Passes in front. It beginning of the heel strike phase. The creates a dorsiflexion moment most activated: Ext Digitorum Longus, Ext Hallucis Longus Since plantar flexion increases the moment After heel strike: It passes from following the heel strike, the activity of the dorsiflexor muscles increases to the back. It creates a plantar compensate for this. performs eccentric flexion moment contraction to prevent the foot from hitting the ground. After foot flat: Max plantar flexion dorsiflexor muscles lose their activity. moment, external forces slide Plantar flexor muscles are activated gradually. forward It creates a dorsiflexor moment by Before the midstance phase, activation of passing from the front while mid- Gastrocnemius, Soleus, Tibialis post, Flexor Digitororum longus, Peroneus Longus increase 67 stance phase  KNEE JOINT ANALYSES BETWEEN HEEL STRIKE AND MID STANCE PHASE 68  KINEMATIC ANALYSIS Just before the heel strike: Full extension Immediately after the heel strike: At 178 degrees of extension Foot flat: In 15-20 degree flexion Midstance: In 10-15 degree flexion (Between these two, the Quadriceps are activated to bring the leg to extension. 69  KINETIC ANALYSIS EXTERNAL FORCES INTERNAL FORCES Before Heel Strike: Passes in front. After heel strike: It passes from Exantric contraction of Quadriceps the back. Foot flat: It passes from the back. Isotonic contraction of Quadriceps Mid stance: It passes from the back. In the early stage of the mid- stance phase, the Quadriceps is active. Towards the end of the mid-stance phase, it slides to the front of the joint center and knee control is passive. 70  HIP JOINT ANALYSES BETWEEN THE HEEL STRIKE AND THE MID STANCE PHASE 71  Kinematic Analysis Heel strike: 30 degree flexion Foot flat: 20 degree flexion Mid stance phase: Neutral 72  Kinetic Analysis EXTERNAL FORCES INTERNAL FORCES Passes in front. Forces flexion Gluteus mx, hamstrings and erector spina active Passes in front. Forces flexion Works with Gluteus max and Add. Magnus. Due to knee flexion, Hamstring activation is decreased Passes from the back. forces the hip to rotate backwards Iliopsoas, Rectus Femoris and abdominals are active. 73 ANKLE ANALYSES BETWEEN THE MID STANCE AND PUSH-OFF PHASES 74 75  Kinetic Kinematic External Forces Internal Forces Mid Stance: Passes 3.5-4 cm 0 3-5 dorsiflexion in front 0 Passes even Heel Off: 15 further. dorsiflexion Activity of Dorsiflexion then 350 plantar flexors moment plantar flexion increases. Passes in Toe Off: 200 tarsometatarsal Plantar flexion level. 76 KNEE ANALYSES BETWEEN THE MID STANCE AND PUSH-OFF PHASES 77  Kinetic Kinematic External Forces Internal Forces Mid Stance: Passes in back. Quadriceps 0 10-15 flexion Flexor moment femoris Gastrocnemius is max. Other plantar muscles; Passes in front. Heel Off: tibialis posterior, soleus, extensor peroneus longus and extension brevis, flexor hallucis moment longus is active after then gastrocnemius. 0 Passes in back. Toe Off: 40 Quadriceps extensor flexion femoris moment 78 HIP ANALYSES BETWEEN THE MID STANCE AND PUSH-OFF PHASES 79  Kinetic Kinematic External Forces Internal Forces Passes in back. Mid Stance: Forces hip to Iliopsoas Neutral extension Heel Off: 10-150 Passes in back. Iliopsoas hyperextension 0 Passes in back. Adductor Toe Off: 20 extensor longus and hyperextension moment is max magnus 80  ANKLE IN SWİNG PHASE Tibialis Anterior Extensor Digitorum Longus Extensor Hallucis Longus Shorten the extremity 81  KNEE IN SWİNG PHASE Continues flexion following toe off. It reaches 650 max max value in mid swing. Functions of Quadriceps femoris after toe off: 1. Adjusting the level of heel off posteriorly 2. Starting the forward swing of the leg 82  At the end of the swing phase, just before the heel strike, the hamstrings are activated. Decelerate the movement of the leg To ensure that heel strike is done correctly and in control. 83  HIP IN SWİNG PHASE Begining of thephase: Neutral Till mid swing: Flexion start. Mid swing till the end: 25 flexion 0 84 GAIT ANALYSIS 85  STEP LENGTH The distance between the point where one heel touches the ground and the point where the other heel touches the ground is «step length» 35 - 41 cm  STRIDE LENGTH Distance between points where the same heel touches the ground twice in a row 70- 82 cm  STEP WIDTH Width between the vertical axes of the two feet Normally 7-8 cm > 10 cm: Abd.