1. The Gait Cycle:

2. Walking – The Stance Phase

3. 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

4. Walking – The Swing Phase

5. 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

6. 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 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)

8. 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

9. Running – A Gait Cycle

10. 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