Transcript Chapter 9
Chapter 9 Evaluation of Gait Introduction Gait Analysis – functional evaluation of a person’s walking or running style Systematic method of identifying specific deviations in the gait pattern and determining their cause and implications Goals of analysis vary Introduction Dysfunctional or antalgic gait can arise from acute or chronic injury or improper biomechanics Prohibits normal weight-bearing Influences stresses placed on joint surfaces Predisposes patient to additional injury Rehabilitation and/or correction of biomechanics Observation Techniques Process of gathering, organizing, and interpreting sensory information Observation best obtained by using stopaction video Video can be slowed down and replayed Permanent record on file Limb position, ROM, speed of motion, force production, timing of events in gait cycle Observation Techniques Treadmills Pros and cons Stride length Guidelines for observational gait analysis Page 304 Auditory information (cadence) Correlate findings with orthopedic and postural evaluations Figure 9-2, pages 305-306 Gait Cycle Represents the combined function of the lower extremity, pelvis, and spinal column Walking – cyclical motion, bipedal Center of gravity Easily displaced in the desired direction Positioned high, second sacral segment Greater portion of body weight is located in trunk, head, and shoulders Figure 9-3, page 307 Gait Cycle Components of normal walking gait do not transfer to most athletic activities Specific to the motion: Force distribution across the foot, muscle actions, joint motions, and center of gravity Normal Gait Normal cadence = 107 (+ 2.7) steps per minute Normal stride length = 75 (+ 1.6) cm Symmetrical and uninterrupted rhythm Terminology – Table 9-1, page 307 Rancho Los Amigos Normal Gait Affected by intrinsic factors Joint ROM Muscle strength Body type Gender Affected by extrinsic factors Incline of surface Surface type footwear Gait Phases Stance Phase Initial contact of heel until toe breaks contact with surface (toe-off) Swing Phase Between toe-off and next initial contact Open kinetic chain, non-weight bearing Limb repositions itself Figure 9-4, page 308 Gait Phases During walking – one leg is in stance phase while the other leg is in the swing phase Efficient walking Minimal upward and side-to-side motion Maximal forward motion Rotation of pelvis in transverse plane adds to step length Stance Phase 60% of gait cycle Closed kinetic chain during weightbearing, allows forces from lower extremity to be transmitted to ground, producing movement Leg decelerates just before initial contact, preventing injury to heel Enables balance and push off Stance Phase 5 distinct periods: Initial contact Loading response midstance terminal stance Preswing Box 9-1, pages 310-311 Initial Contact Begins with foot touching surface Contact should be through lateral aspect of plantar surface Opposite limb is ending with toe-off Subtalar joint – supinated @ 5 degrees Talocrural joint – dorsiflexed Both limbs in contact with surface Loading Response Response to absorption of body weight by initiating flattening of the foot Subtalar joint – pronates Unlocks midtarsal joints, allowing foot to become flexible Tibial internal rotation – increased medial forces at foot, leg, knee Talocrural joint – plantarflexes Loading Response Muscle support – decelerates pronation and plantarflexion Hip remains flexed Period lasts until double limb support has ended Midstance Begins as body weight moves over stationary support limb and ends when center of gravity is directly over the foot Subtalar joint – supinates Locks midtarsal joints, makes foot a rigid lever Preparing for efficiency during propulsion Talocrural joint – dorsiflexes Hip moves into extension Terminal Stance Starts as center of gravity passes over the foot and ends just before the contralateral limb makes contact with the ground Body moves forward with weight shifting over metatarsal heads until contralateral limb provides new base of support Toes extended, tibia externally rotated Subtalar joint – supinated Hip and knee continue to flex Preswing Transitional period of double support Limb is uploaded and prepared to swing Begins with initial contact of contralateral limb and ends with toe-off of stance limb Swing Phase Begins as soon as the toes leave the surface and terminates when the limb next makes contact with the surface Gravity assists in pulling leg mass down Momentum gained at toe-ff helps carry leg through the swing phase Three periods Initial swing, midswing, terminal swing Box 9-2, pages 312-313 Initial Swing Begins at the point where toes leave the ground and continues until knee reaches its maximum range of flexion (@ 60O) Femur advances Ankle dorsiflexes, allowing toe clearance Subtalar joint - pronation Midswing Knee extends until tibia is vertical to surface Thigh continues to advance, toe clearance is ensured, propulsion continues Talocrural joint – dorsiflexed to neutral or slight dorsiflexion Terminal Swing Occurs from end of midswing to initial contact period of the stance phase Trunk is erect Thigh decelerates for heel contact Knee extends to create step length for heel contact Step length – distance traveled between initial contacts of right and left foot Subtalar joint - supination Qualitative Observation of Gait Rise and fall of the body in vertical direction = 5cm Path of center of gravity is sinusoidal or a smooth curve No sharp braking As speed increase, arm action is involved Questions to address during gait analysis Page 309 Running Gait Series of smoothly coordinated jumps executed from one foot to the other foot Purpose – to move body from one position to another at a moderate to fast speed As speed increase – techniques changes Arm swing ROM, stride length, cadence, and knee flexion ROM Running Gait Muscular force and speed of contraction also change Control pronation during loading response and initiate supination prior to preswing Walking versus Running Gait 2 distinct differences: Flight phase – neither foot is in contact with the ground At no time are both feet in contact with the surface at the same time Stance phase Walking – 62% of the cycle; Running – 33% of the cycle Same joints used Differences in degrees of motion and timing of actions Figure 9-5, page 314 Ground Reaction Forces Every contact of the foot with the surface generates an upward reaction force GRFs are measured and compared Figure 9-6, page 315 Vertical component of GRF during running is 2 to 3 times the runner’s body weight Classified as rearfoot, midfoot, or forefoot strikers Ground Reaction Forces Factors influencing GRF patterns: Running speed Running style Ground surface Grade of incline Shoes/orthotics Questions to address during observation of running gait Page 315 Pathologies Affecting the Gait Cycle Box 9-3, page 316 Table 9-2, page 317 Acute Lower Extremity Strains and Sprains Overuse Injuries Leg Length Discrepancies Functional Bracing