Gait Mechanics PDF - Gait Cycle, Analysis, Patterns - 2024 EXAM PREP

Session 5 Gait Mechanics Gait Cycle When observing gait pattern, you only observe one limb. The gait cycle begins when the heel of the referenced (observed) extremity contacts the ground and ends when the heel of the same extremity contacts the ground again. Divided into 2 phases: stance and swing...

Session 5 Gait Mechanics Gait Cycle When observing gait pattern, you only observe one limb. The gait cycle begins when the heel of the referenced (observed) extremity contacts the ground and ends when the heel of the same extremity contacts the ground again. Divided into 2 phases: stance and swing Stance phase: o Interval in which the foot of referenced lower extremity is in contact with the ground o Constitutes 60% of gait cycle o A single gait cycle contains right and left stance phases Swing phase: o Interval in which the foot of referenced lower extremity is not in contact with the ground o Constitutes 40% of gait cycle o A single gait cycle contains right and left swing phases Double support time Refers to the two periods in a gait cycle in which body weight is transferred from one foot to the other and both right and left feet are in contact with the ground at the same time. o One period occurs early in stance phase of referenced extremity and the other occurs late in stance phase of the referenced extremity. Around 20% of gait cycle is spent in double limb support and 80% in single limb support. Gait values Stride: distance between successive points of heel contact of the same foot. o Involves 2 steps (left and right) o Stride is equal to a gait cycle o Average distance: ~1.4 meters 2024 Written Course Manual | Page 179 of 383  Step: distance between the heel contact point of one foot and that of the other foot. o Example: left step length is measured from point of right heel contact to point of left heel contact o Average distance: ~0.7 meters Velocity = total distance traveled in a given amount of time. o Average speed: ~1.3 meters per second Rancho vs. Traditional Gait Classification Know traditional gait terminology as well as Rancho Los Amigos Terminology – know which is included in stance and swing phase. Stance Swing Traditional Rancho Los Amigos Traditional Rancho Los Amigos Heel strike Initial contact Acceleration Initial swing Foot flat Loading response Mid-swing Mid-swing Midstance Midstance Deceleration Terminal swing Heel off Terminal stance Toe off Pre-swing Gait Analysis Portion of Double vs Definition Muscular Contractions Joint ROM Phase Single Limb Requirements* Support Stance Initial contact Double Beginning Breaking response in gait Hip: 30° flexion (heel strike) Marks the of stance where the most muscles are Knee: 0°- 15° beginning phase working eccentrically flexion of initial Hip extensors contract Occurs double eccentrically to slow Ankle: 0°- 15° PF when heel limb contacts down and stabilize the support the ground limb for initial contact Quadriceps contract concentrically initially to hold knee in extension and then eccentrically to control the amount of knee flexion on contact Tibialis anterior contracts eccentrically to prevent foot slap Loading Double Occurs Tibialis anterior Hip: 30° flexion - response (foot after initial continues to contract 5° flexion flat) contact eccentrically to control until 2024 Written Course Manual | Page 180 of 383  elevation of plantar flexion moment Knee: 15° - 5° opposite at ankle flexion limb - bodyweight Quadriceps initially Ankle: 15° PF -10 contract eccentrically to DF is stabilize knee and transferred counteract the flexion on to the moment and then supporting contract concentrically limb to move knee towards extension Midstance Single Begins Hip extensors and Hip: 5° flexion - 10° Initial when the quadriceps undergo hyperext period of opposite concentric contraction to Knee: 5° flexion - single limb limb leaves advance body forward 0° (neutral) support the ground over stance leg and the Ankle: 10° - 15° DF body is Glute medius contracts eccentrically throughout aligned stance to control pelvic directly alignment over the stance leg Gastrocs and soleus eccentrically contract to control advancement of tibia over foot Terminal Single Begins Gastrocs, soleus, Hip: 10° hypertext stance (heel Last when the peroneals, and flexor - 0° (neutral) off) portion of supporting hallucis longus contract heel rises concentrically to Knee: 0° - 5° single limb flexion support from the plantarflex the ankle ground and Ankle: 15° DF - 20° continues ILIOPSOAS AND QUADS ECCENTRIC PF until the opposite Start to see heel initiation of touches the windlass mech ground (PF, great toe extension and supination of foot) Pre-swing Double Begins from Hip flexors contract to Hip: 0° (neutral) - (toe off) Start of the initial propel advancing limb 20° flexion second contact of forwards opposite Knee: 5° - 40° double Knee flexion is relatively flexion limb limb to just passive and due to PF stance in prior to Ankle: 20° PF -0° generating push off the gait elevation of (neutral) cycle reference Ankle PF’s continue to limb concentrically contract Great toe: 65° - 70° extension at for push off toe off Windlass mech in full effect *Demonstrates ROM changes throughout each phase (transition from start of phase into subsequent phase) 2024 Written Course Manual | Page 181 of 383  Portion of Double vs Definition Muscular Contractions Joint ROM Phase Single Limb Requirements* Support Swing Initial swing Single From Main acceleration phase Hip: 20° - 30° (acceleration) elevation of flexion Hip flexors (iliopsoas, limb to point rectus femoris) Knee: 40°- 60° of maximal concentrically contract to flexion knee flexion advance the swinging leg Ankle: 0° Hamstring contract (neutral) concentrically to flex knee throughout swing Ankle dorsiflexors concentrically contract to ensure foot clearance Mid-swing Single From Quadriceps begin to Hip: 30° flexion maximal concentrically contact to knee flexion extend the knee Knee: 60°- 30° flexion to point Ankle dorsiflexors where tibia is Ankle: 0° continue to concentrically vertical contract Terminal Single From point Eccentric activation of Hip: 30° flexion swing where tibia is hamstring muscles Knee: 30° (deceleration) vertical to decelerates forward flexion - 0° just prior to motion of thigh (neutral) initial contact Ankle: 0° *Demonstrates ROM changes throughout each phase (transition from start of phase into subsequent phase) Summary of normal ROM required for gait Joint ROM Requirements Hip 10° extension - 30° flexion Knee 0° - 60° flexion Ankle 15° DF - 20° PF Great toe 0° - 65°/70° extension 2024 Written Course Manual | Page 182 of 383 Four main challenges of gait: Maintaining upright posture Maintaining equilibrium Control of foot trajectory and ground clearance Control of multiple body segments Three main tasks in gait: Weight acceptance Maintenance of stability during single leg support Limb advancement (swing) Normal wear pattern on shoes: Increased wear over the lateral portion of the outer sole at the heel. Even wear along the area corresponding to the 1 st, 2nd, and 3rd MTP joints. Even wear over the 1st, 2nd, and 3rd MT heads. Orthotics: It is not entry level practice to prescribe orthotics. Exercise should be your first treatment to correct biomechanical faults. Example: excessive pronation. In a scenario where a question states that exercise treatment has not worked, you would want to refer to an orthotist for custom orthotics. Gait Patterns Antalgic gait: o Antalgic gait is a gait pattern seen when a patient has pain in one of their lower extremities o Reduce weight bearing on the affected limb o In order to reduce weight bearing on the affected limb, there will be decreased step length of the unaffected limb resulting in decreased stance time on the affected limb o Side flexion towards affected limb during stance if hip is the source of pain o Side flexion away from affected limb during stance if knee or ankle/foot are the source of pain o Reduced cadence o Cane held contralateral to affected limb Foot drop: ankle DF weakness results in abnormal compensatory gait patterns. o Steppage gait: ▪ Patient cannot DF, results in excessive hip and knee flexion to clear the foot o Foot slap: ▪ Patient has weak or absent dorsiflexors and the foot slaps down on the ground o Circumduction of affected limb during swing to clear the swing leg o Hip hiking of affected limb during swing 2024 Written Course Manual | Page 183 of 383  Abducted lurch: o Patient leans over the affected/weak hip to place the center of gravity over the hip o Compensatory technique for a gluteus medius muscle weakness Gluteus maximus gait: o Backward trunk lean or throwing the trunk backward after initial contact may be due to weakness of hip extensors (gluteus maximus) Parkinsonian gait: o Trunk, head, neck forward and flexed (kyphotic head forward posture) o Narrow base, small shuffling steps o Lack of arm swing and trunk rotation o Tend to fall forward and to increase speed (festination) o Episodes of freezing Ataxic gait: o Wide base of support due to poor balance o Arms held away from body in “high guard” to improve balance o Irregular stepping patterns (distance and direction) o Slow initiation of forward progression of limb which is suddenly flung forwards unexpectedly and slaps the ground on contact o Unsteady gait pattern with irregular, staggering movements o Veering to one side or the other Scissoring gait: o Most commonly seen in spastic cerebral palsy o Legs cross midline due to spasticity of adductors Knee hyperextension o Due to weak knee extensors o Inability to take full weight on limb without hyperextending the knee to prevent buckling Hemiplegic gait: o Stance: ▪ Weak hip abductors resulting in Trendelenburg ▪ Knee hyperextension due to quadriceps spasticity, loss of ankle DF ROM, poor proprioception/control, weak quadriceps OR knee flexion throughout stance due to knee flexion contracture, poor proprioception/control ▪ Loss of heel strike due to ankle DF weakness, PF contractures ▪ Varus foot in stance due to weak peroneals, hyperactive/spastic tibialis anterior, tibialis posterior, toe flexors, soleus ▪ Decreased stance time on affected limb due to short contralateral step length o Swing: ▪ Inadequate hip flexion for step due to hip weakness ▪ Spastic adductors resulting in scissoring of affected limb ▪ Poor foot clearance due to weak hip, knee or ankle dorsiflexors, spastic quadriceps, spastic PF’s or PF contractures 2024 Written Course Manual | Page 184 of 383  Trendelenburg sign and gait: o Trendelenburg sign: when standing in single leg stance, the opposite pelvis (non- standing leg) drops ▪ E.g. The pelvis dips on the contralateral side o Trendelenburg gait: during gait, the weak abductors cause the contralateral side to dip o Compensated Trendelenburg: patient will side flex ipsilaterally over standing leg to compensate for weak glute medius and minimus o Causes: ▪ Gluteus medius and minimus weakness ▪ Lesion in superior gluteal nerve – common during pregnancy o Refer to video in additional resource list: Trendelenburg Gait o See Appendix Trendelenburg sign and gait in Session 1 2024 Written Course Manual | Page 185 of 383