 Initial Contact  Loading Response  Mid-Stance  Terminal Stance  Pre-Swing  Initial Swing  Mid-Swing  Terminal Swing

Normal Human Locomotion

Normal Human Locomotion

    INITIAL CONTACT Hip Knee Ankle Goal = = = = Flexed Nearly Flexed Neutral Begin Stance - GRF is Posterior to ankle, creating PF MOMENT

INITIAL CONTACT

Normal Human Locomotion

 GRF is Anterior to Knee and Hip, creating EXTENTION at knee, FLEXION at hip  Passive extension aided by Quads and Hamstrings  Gluts, Hamstrings HIGHLY active to overcome vector

Normal Human Locomotion

LOADING RESPONSE    Hip = Knee = Ankle = Flexed is Flexing Plantarflexing  Goals = Weight Acceptance, Shock Absorption, Advance body over heel rocker  GRF is still Posterior to Ankle, now Posterior to Knee

Normal Human Locomotion

LOADING RESPONSE  Eccentric Control of Pretibials helps create the 1 st ROCKER  15-18º Knee flexion as Shock Absorber  30º Hip Flexion maintained, creating 2 nd highest Torque, only to dorsiflexion

Normal Human Locomotion

LOADING RESPONSE  Hamstrings help during LR to stabilize hip, prevent trunk flexion  This is taken over by Gluts as stance progresses  Eccentric action of Gluts, Hams, Adductor Magnus

LOADING RESPONSE  Point of PEAK PELVIC OBLIQUITY and maximum STANCE PHASE KNEE FLEXION occurs here  Opposite toe-off occurs here – helps to decrease overall vertical displacement of the body

Normal Human Locomotion

    MIDSTANCE Hip Knee Ankle Goal = = = = foot Extending Extending Dorsiflexing Advance body over stationary  GRF moves anterior to ankle, goes from post to ant. at knee

Normal Human Locomotion

MIDSTANCE  Early need for knee extensors, but not during late midstance due to placement of the force vector  Early need for soleus for eccentric control, more on gastroc as knee extends for mechanical efficiency.

Normal Human Locomotion

MIDSTANCE  Hip flexion decreases from 30º to 10º as midstance progresses  Vertical GRF reduced by upswing of contralateral side – still produce 2 ½ times body weight at peak on same side femoral head  Gluts active as extensor early, abd. late

Normal Human Locomotion

MIDSTANCE In Amputees, the Vertical GRF is INCREASED on sound limb due to prosthetic foot - This is less with Flex foot than with SACH foot; reinforces need to know componentry

Normal Human Locomotion

MIDSTANCE  Hip flexion decreases from 30º to 10º as midstance progresses  Vertical GRF reduced by upswing of contralateral side – still produce 2 ½ times body weight at peak on same side femoral head  Gluts active as extensor early, abd. late

Normal Human Locomotion

    TERMINAL STANCE Hip Knee Ankle Goal = = Extending Extended, then flexing = Dorsiflexed = Advance body over forefoot rocker - GRF creates STRONG DF moment

Normal Human Locomotion

TERMINAL STANCE - Movement over the Forefoot Rocker occurs - Highest demand on gastroc-soleus as body vector moves outside the boundaries of the foot - Max dorsiflexion occurs at TOE-OFF

Normal Human Locomotion

TERMINAL STANCE - NO muscle action at knee – this extension is created by external torque and GRF passing far anterior to joint - Joint motion and forward progression created by momentum and swing of contralateral limb

Normal Human Locomotion

TERMINAL STANCE - Mild hip extension torque created - Passive hip extension aided by position of vector posterior to hip - TFL helps control extension torque - Vertical Magnitude of vector is similar here to Loading

Normal Human Locomotion

    PRESWING Hip Knee Ankle Goal = = = = Flexing Flexing Plantarflexing Prepare for swing - GRF creates passive knee flexion, DF torque

Normal Human Locomotion

PRESWING -During unloading of limb, PF activity is DECREASED; NO active push off during normal gait - DF torque decreases as MP joints reach 60° of extension

Normal Human Locomotion

PRESWING - Hip flexes using MOMENTUM, plus rectus femoris, sartorius and add. Longus - Add. Longus helps counteract hip abd. Created by contralateral off-loading - PELVIC ROTATION helps balance the limbs out

Normal Human Locomotion

    INITIAL SWING Hip Knee Ankle Goal = = = = Flexing Flexing Dorsiflexing Clear foot and advance limb - Pre-tibs are active, helping reduce PF angle from 20° to around 5°

Normal Human Locomotion

INITIAL SWING - Knee continues to flex to 60°, assisted by MOMENTUM plus biceps femoris (short head), sartorius and gracilis - Hip flexed to 20° with help if iliacus, gracilis, sartorius, which help to flex both hip AND knee

Normal Human Locomotion

    MIDSWING Hip Knee Ankle Goal = = = = Flexing Extending Dorsiflexing Advance limb and clear foot - Rapid knee ext. from 60° to 30° is PASSIVE, assisted by MOMENTUM

Normal Human Locomotion

MIDSWING - EMG shows only MILD hip flexor activity, maintaining 30° angle - Gracilis, sartorius, iliacus stop in early midswing, hamstrings begin to decelerate limb - Rest of limb advancement is MOMENTUM

Normal Human Locomotion

    TERMINAL SWING Hip Knee Ankle Goal = = = = Flexed Extending Neutral Advance limb - Pretibs now act to place foot properly on the ground

Normal Human Locomotion

TERMINAL SWING - Quads active at end of TS, help fully extend knee along with PELVIC ROTATION - Eccentric hamstrings, Gluts help control hip and knee to control stride length

When are Muscles Active, When are they not?

 Initial Contact and Loading Response - Focus often on strong contraction of knee ext. in BK patients – not necessary due to strong ext. moment - Use of Gluts/Hamstrings EARLY in stance phase to overcome strong FLEXION vector at hip - Focus on HIP/BACK extention, as hams/gluts used primarily to stabilize back and counteract hip flexion moment

When are Muscles Active, When are they not?

 Midstance and Terminal Stance - Remember, quads active EARLY in midstance, but vector again moves ANTERIOR, becoming passive - Vector moves ANTERIOR to ankle, now fully reliant on prosthetic foot

Understand the Components!!!!

 Get patient to understand the give of the foot and knee they are on to assist with this stage of gait

Understand the Components!!!!

 Due to lack of MTP extension, forces are transmitted up the chain to knee/hip. Pt MUST allow MOMENTUM to transfer over the foot to allow for minimizing forces at higher joints

When are Muscles Active, when are they not?

 Pre-Swing and Initial Swing - Knee flexion throughout this phase done by MOMENTUM, so use to your advantage - All action at the knee and below can be controlled with proper PELVIC motion and use of proper hip muscles to create vector

When are Muscles Active, when are they not?

 Pre-Swing and Initial Swing - Ipsilateral Adductors help propel hip forward while counteracting strong abduction vector during off loading - USE BOTH actions to your advantage during exercise prescription – adductors are BOTH stabilizers and protagonists

When are Muscles Active, when are they not?

 Mid-Swing and Terminal Swing - Knee extension in Mid-Swing is PASSIVE. In AK’s, extension assist components help with this action - ipsilateral hip musculature stops here, now Hamstrings begin to fire to slow knee ext, prepare for stabilization of back

When are Muscles Active, when are they not?

 Mid-Swing and Terminal Swing - Pre-tibs prepare foot in TS, but not appropriate for amputees. Foot position is essential to maximize properties of prosthetic foot – FOOT PLACEMENT ACTIVITIES - End range Pelvic Rotation, quads are essential here to prepare for IC

IMPORTANT EXERCISES

1. Eccentric Hamstrings, Concentric Quads 2. Adductors as both STABILIZER and PRIME MOVER 3. Creating MOMENTUM, using it to your advantage 4. QUICK BURST exercises

IMPORTANT EXERCISES

1. SPEED OF CONTRACTION - too much time does not allow for release of normal energy and eliminates importance of MOMENTUM in helping propel body forward 2. TRANSITION EXERCISES - moving between cycles of gait, when to transition to next mode of ms contraction