Phases of Gait cycle:
One gait cycle is completed from heel-strike till start of next heel-strike.
Two main phases:
- Stance phase:- -60% of the gait cycle
-during this period, the foot is on the ground
-body weight on the single leg
- 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)- 1st contact of foot with ground
–Muscles: Hip Extensors (stabilize hip); Eccentric contraction of Quadriceps & Tibialis anterior.
- 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).
- Mid stance- initiation of single limb support
– alignment and balancing of body weight on the reference foot
-Muscles: Contraction of Hip extensors & Quadriceps
- 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.
- Pre-swing- just before the ‘Swing phase’, 2nd 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).
- Mid-swing- from the knee flexion to the point of vertical tibia (foot clearance).
– Muscle: Contraction of Ankle dorsiflexors →for foot clearance.
- Terminal Swing: – after ‘mid-swing’ just prior to ‘initial contact’
– From Tibia-vertical to just before heel-strike.
–Muscles: Hamstrings contraction