Gait

RLA - Gait Phases

Stride (100%)Stance (60%) Swing (40%)

LoadingResponse(0 - 10%)

Midstance(10 - 30%)

Terminal Stance(30-50%)

Pre-Swing

(50-60%)

InitialSwing

(60-73%)

Midswing(73-87%)

TerminalSwing

(87-100%)DoubleSupport(10%)

DoubleSupport(10%)

Traditional Phases of Gait

Stance Phase (60%) Heel-strike (contact) Foot-flat Mid-stance point Heel-off Toe-off

Traditional Phases of Gait

Swing Phase (40%) Acceleration: TO Acceleration Midswing: Acceleration MSw Deceleration – MSw Deceleration

Ranchos Los Amigos (RLA)

Traditional references “Reference Limb” only

RLA references both limbs

RLA defines swing intervals more precisely

RLA Stance Phase

60% of Gait CycleLoading Response (LR) 0 - 10% [DS]Midstance (MSt) 10 - 30%Terminal Stance (TSt) 30-50%Preswing (PSw) 50-60% [DS]

Instantaneous Events

Initial Contact (IC)

Toe-off (TO)

RLA Swing Phase

40% of Gait CycleInitial Swing (Isw) 60 - 73%Midswing (MSw) 73 - 87%Terminal Swing (TSw) 87 - 100%

Gait Phases

RLA

Locomotor UnitPelvisLE

Passenger UnitHAT

Locomotor Functions

PropulsionStabilityShock AbsorptionEnergy Conservation< 2” displacement

Task A: Weight Acceptance

IC

LRIC opposite foot lifted (end of DS)

0 - 10%

Task B: Single Limb Support

MSt (initiation of SLS)opposite foot lifted BW over forefoot10 - 30%

TSt (completes SLS)Heel rise of RL IC of opposite limb30 - 50%

Task C: Limb Advancement (Stance)

PSw (initiation of second phase of DS)IC of opposite limb ipsilateral toe-

off50 - 60%

Task C: Limb Advancement (Swing)

ISwToe-off swing foot is opposite

stance limb

MSwSwing limb opposite stance limb

swing limb tibia is vertical

Task C: Limb Advancement (Swing)

TSwvertical tibia IC

GRFV or Body Vector

Effect of body weight

HAT COG COP

Relate GRFV to joint centers to determine:

magnitude and direction of joint instability

GRFV

HAT COG (T10)

COP

GRFV

GRFV

Moment

External

Internal

Ankle ROM

Ankle Moment

Knee ROM

Knee Moment

Hip ROM

Hip Moment

Rockers

Heel

Ankle

Forefoot