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The Gait Cycle:

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Walking – The Stance Phase

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Components of the Stance Phase

• Stance phase comprises 60% of the gait cycle• Heel strike – moment when the heel first strikes the

ground• Foot flat – from heel strike to when the full foot is

in contact with the ground• Midstance – body weight is directly over the stance

leg• Heel off – moment the heel of the stance leg leaves

the ground• Toe off – when only the toe of the stance leg is in

contact with the ground

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Walking – The Swing Phase

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Components of the Swing Phase

• Swing phase comprises 40% of the gait cycle• Acceleration – the toe of the stance leg leaves the

ground and begins to swing forward• Midswing – the swinging leg is directly beneath

the body• Deceleration – the swinging leg continues forward

towards knee extension but is slowing down as it travels, stopping just prior to full knee extension and heel contact with the ground

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Range of motion at the joints• Trunk - As left leg moves forward, pelvis rotates clockwise

as viewed from above 7 deg• Hip Joint (30 deg flex at HS strike, 180 deg at TO)

– Stance - extension, adduction, internal rotation– Swing - flexion/extension, abduction, ext rotation

• Knee joint - 180 deg at HS, 160 deg at mid-stance• Ankle joint - Neutral at HS, hinges down during support, and

plantar flexes at TO . ROM 30 deg• COM displacement +5 cm bilaterally and vertically (Fig 15.3)

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Running Analysis…...

• Running is similar to walking BUT, it differs significantly in a number of ways, for example:

• No period of “double support”• Float periods (both feet airborne)• Requires greater balance• Requires greater strength• Requires greater ROM at hip, knee, and ankle joints• Involves greater excursion of center of mass• Involves greater ground reaction forces

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Running – A Gait Cycle

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Muscle Activity in Running...

• Glut. Max. & med. -- active at the beginning of the stance phase (concentrically) and again at the end of the swing phase (eccentrically).

• Iliopsoas -- active during a portion of the swing phase (concentrically).

• Quadriceps -- 1st 10% of the stance phase (eccentrically) and last 20% of the swing phase (concentrically).

• Hamstrings -- initial portion of the swing phase (concentric) and at the end of the swing phase (eccentric).

• Plantar flexors (gastrocnemius & soleus) – Mid and latter part of stance phase