As a runner transitions through the gait cycle, which comprises distinct phases such as initial contact, midstance, terminal stance, and swing, various biomechanical factors come into play which are different from the normal gait cycle.

1. By : Jemini Parmar

2. Gait
• Gait is described as the translatory progression of
the body as a whole, produced by coordinated ,
rotatory movements of body segments.

3. Gait cycle
• The gait cycle is the time interval or sequence of
motion occurring between two consecutive initial
contact of the same foot.
• A gait cycle spans two successive events of the
same limb:
1. Stance phase – 60 %
2. Swing phase – 40%

4. Phases and events in gait
• Stance phase
 Initial contact
 Foot flat
 Midstance
 Heel off
 Toe off
• Swing phase
 Early swing
 Mid swing
 Late swing

6. The Running Gait Cycle
• Running is defined as a gait wherein the swing
phase is longer than stance phase, and there are two
periods within the gait cycle when neither lower limb
is in contact with the ground.
• Running requires:
1. Greater balance
2. Greater muscle strength
3. Greater joint range of movement

7. • Greater balance is required because running is characterized not
only by a considerably reduced base of support but also by an
absence of the double-support periods observed in normal walking
and the presence of float periods in which both feet are out of
contact with the supporting surface.
• Muscles must generate greater energy both to raise HAT higher
than in normal walking and to balance and support HAT during the
gait cycle.
• Muscles and joint structures also must be able to absorb more
energy to accept and control the weight of HAT.
• As the body transitions from walking to running , changes occur in
spatial and temporal variables of gait.

9. Phases of running gait cycle
Stance
phase
Absorption
Propulsion
Swing
phase
Initial
swing
Terminal
swing

10. Stance phase
1.Absorption
•The time from initial contact of the foot to the time of
midstance.
•About 80% of runners make initial contact on the heel.
•As the name of this phase implies, its purpose is to absorb
the forces of the foot impacting with the ground.
2.Propulsion
•Body’s COM moves over the weight-bearing foot at
midstance, the opposite limb is swinging forward.

11. • While the stance heel is moving off the ground as it
initiates its forward propulsion, the swing leg continues
its forward advancement and begins preparations for
stance.
• Once the foot leaves the ground, the stance phase ends,
and the limb moves into the first double float phase.

12. Swing phase
1. Initial swing
• The first half of initial swing is the first double float
phase when both limbs are off the ground.
2. Terminal swing
• The second half of the swing phase is marked by a
change from acceleration to deceleration in preparation
for initial contact.

13. Kinematics
• kinematics deals with movement without consideration of
the forces that cause that movement.

14. Joint motion
Initial
contact to
midstance
Midstance
to toe off
Initial
swing
Mid swing Terminal
swing
Hip joint 45° - 20°
flexion
20° flexion
- 5°
extension
5° - 20°
extension
5° - 20°
extension
65° - 40°
flexion
Knee joint 20°- 40°
flexion
40° - 50°
flexion
15°- 5°
flexion
15°- 5°
flexion
130°- 20°
flexion
Ankle joint 5° PF - 10°
DF
10°-20° DF 20°-30° PF 20°-30° PF 0 - 5° DF to
5° PF

15. Trunk &
pelvis
Hip joint Knee joint Ankle &
foot
Sagittal
plane
Increase speed ,
Lowered COM,
Progressive
forward lean of
trunk,
Anterior pelvic
tilt,
Similar to walking,
Except extension
in toe off,
Terminal swing –
hip moves towards
extension ,
Maximum flexion –
terminal swing
Similar to walking,
Stance phase –
knee moves from
45° (absorption) to
20° extension
(propulsion),
Midswing – knee
flex 90° to 130°
flexion,
20° dorsiflexion
before midstance ,
Propulsive phase ,
Plantarflexion
Frontal
plane
Trunk lean
towards weight
bearing foot,
Adduction – initial
contact ,
Propulsive phase ,
Abduction – toe off
Foot hits ground-
knee abduction ,
Then 12°
adduction by
midstance
Subtalar joint - 10°
inversion ,
Immediately
eversion,
Transverse
plane
Upper spine -
rotates forward in
with the arm
on(ipsilateral ),
Lower spine -
backward
Medial rotation –
absorption phase ,
Midstance ,
Lateral rotation –
toe off
Initial contact –
lateral rotation ,
Medial rotation –
absorption phase
Weight bearing
talus adducts
causing the tibia
medially rotate,

16. Muscle activity
• Gluteus maximus and gluteus medius are both active
at the beginning of stance phase, and also at the end of
swing phase.
• Tensor facia lata is active from the beginning of stance,
and also the end of swing phase. It is also active
between early and mid swing.
• Adductor Magnus is active for about 25% of cycle, from
late stance to early part of swing phase.
• Iliopsoas activity occurs during swing phase for 35-
60% of cycle.

17. • Quadriceps works in an eccentric manner for the initial
10% of the stance phase. It stops being active after the
first part of the stance phase, there is then no activity
until the last 20% of swing phase. At this point it
becomes concentric in behaviour so it can extend the
knee to prepare for heel strike.
• Medial Hamstrings become active at the beginning of
the stance phase(18-28% of stance), they are also
active throughout much of the swing phase(40-58% of
initial swing then the last 20% of swing).

18. • Gastrocnemius muscle activity starts just after loading
at heel strike, remaining active up until 15% of the gait
cycle . It then re-starts its activity in the last 15% of the
swing phase.
• Tibialis anterior muscle is active through both stance
and swing phases in running. It is active for about 73%
of the cycle (compared to 54% when walking). The
swing phase when running, is 62% of the total gait cycle,
compared to 40% when walking, so TA is considerably
more active when running. Its activity is mainly
concentric or isometric, enabling the foot to clear the
support surface during the swing phase of the running
gait.

19. Kinetics
1. Internal forces
• important muscle groups producing power for running
comprise the hip flexors, extensors, abductors, knee
extensors, and gastrocnemiussoleus groups.
• During the first part of stance when the COM is behind the
foot, the gluteus maximus and hamstrings must extend the
hip to move the body forward.
• Once the COM moves over and past the foot, the quadriceps
extends the knee and calf muscles plantarflex the ankle to
continue to propel the body forward by pushing it ahead.

20. 2 . Ground reaction force
•Created between foot and the ground , in which the foot and
ground exert an equal and opposite force on each other.
•The direction and magnitude of the ground reaction force is
determined by the position and acceleration of the runner’s
center of mass.
•After maximum velocity is reached, the center of mass moves
backward.
•A forward trunk lean and pelvic tilt keep the GRF in a position to
allow forward acceleration.

21. Elastic Support Strategy
• In runners the diagonal
elastic support mechanism is
utilised. This is produced by a
constant diagonal stretch and
release that is enabled by the
body’s counter rotation.
• The force continually flows up
and down these force
pathways alternately. The
pattern of force distribution
prevents force being
concentrated in one area, but
allows wide distribution of
force throughout the body.

22. Rotation through the Kinetic Chain
• The kinetic chain can be
described as a series of joint
movements, that make up a
larger movement .
• Running mainly uses sagittal
movements as the arms and legs
move forwards.
• There is also a rotational
component as the joints of the
leg lock to support the body
weight on each side.
• There is also an element of
counter pelvic rotation as the
chest moves forward on the
opposite side.

23. References
• Levangie, Pamela K., and Cynthia C. Norkin. Joint
structure and function: a comprehensive analysis. FA
Davis, 2011.
• Houglum PA, Bertoti DB. Brunnstrom's clinical
kinesiology. FA Davis; 2011 Dec 7.
• Houglum PA. Therapeutic exercise for musculoskeletal
injuries 4th edition. Human Kinetics; 2016 May 18.