Phases of Gait cycle:

One gait cycle is completed from heel-strike till start of next heel-strike.

Two main phases:

1. Stance phase:- -60% of the gait cycle
   -during this period, the foot is on the ground
   -body weight on the single leg
2. Swing phase:- -40% of the gait cycle
   -the foot off the ground moving forward
   -the limb advancement

• Step: the distance between the successive initial contact (heel-strike) of the opposite feet.
• Stride:  the distance between any two successive points of initial contact(heel strike) of the same foot. [Stride length=2x Step length] in a normal Gait.
• Walking Base/Stride Width: the side-to-side distance between the ‘line of step’ of the two feet.
• Cadence: the number of steps per unit time. In a normal gait, Cadence≈100-115 steps/minute.
• Comfortable Walking Speed: a speed with least energy consumption per unit distance. ~80 metre/minute in a normal gait.

Stance phase: further divided into-
1. Initial Contact (heel strike)- 1^st contact of foot with ground
–Muscles: Hip Extensors (stabilize hip); Eccentric contraction of Quadriceps & Tibialis anterior.

2. Loading Response- initiation of double limb stance
   – follows initial contact until elevation of opposite limb
   -the weight transferred onto the referenced leg
   – important for weight-bearing, shock-absorption & forward progression.
   –Muscles: Ankle dorsiflexors (Tibialis anterior)- eccentric contraction to control plantar flexion moment;
   Qudriceps contraction for kee stabilization & to counteract the flexion moment (about the knee).
3.  Mid stance- initiation of single limb support
   – alignment and balancing of body weight on the reference foot
                    -Muscles: Contraction of Hip extensors & Quadriceps
4. Terminal stance– single limb support
   – the heel of reference foot rises while the toes is still in contact with the ground until the opposite heel touches the ground
   –Muscles: Tibialis posterior, Toes flexors.
5. Pre-swing- just before the ‘Swing phase’, 2^nd double limb support
   – from initial contact of opposite foot to just prior to elevation of the reference foot
   –Muscles: Hip flexors

 

 

Swing phase: Initial swing, Mid-swing, Terminal swing.
1. Initial swing (Toe-off)- initiation of single limb support for opposite limb
– from elevation of the reference limb to the point of maximal knee flexion
–Muscles: concentric contraction of hip flexors →advancement of the swinging limb (the reference leg).

2. Mid-swing- from the knee flexion to the point of vertical tibia (foot clearance).
   – Muscle: Contraction of Ankle dorsiflexors →for foot clearance.
3. Terminal Swing: – after ‘mid-swing’ just prior to ‘initial contact’
   – From Tibia-vertical to just before heel-strike.
   –Muscles: Hamstrings contraction