The gait cycle is the fundamental unit of analysis for walking and running, representing the complete sequence of movements from the moment one foot contacts the ground until that same foot contacts the ground again. Understanding the gait cycle is essential for analyzing locomotion, identifying movement abnormalities, and assessing efficiency.
The gait cycle is divided into two main phases:
Stance Phase (approximately 60% of the cycle during walking)
The period when the foot is in contact with the ground, further subdivided into:
- Initial Contact (Heel Strike): The moment the foot first touches the ground
- Loading Response: Weight is transferred onto the stance limb
- Mid-Stance: Body weight passes directly over the stance foot
- Terminal Stance (Heel-Off): Heel begins to lift as body weight moves forward
- Pre-Swing (Toe-Off): Final push-off before the foot leaves the ground
Swing Phase (approximately 40% of the cycle during walking)
The period when the foot is off the ground and moving forward:
- Initial Swing: Foot just leaves the ground and begins moving forward
- Mid-Swing: Swinging limb passes directly beneath the body
- Terminal Swing: Leg decelerates as it prepares for the next contact
Key Characteristics
- During normal walking, there are two periods of double support (both feet on ground) and two periods of single support
- During running, there is no double support phase; instead, there's a flight phase when both feet are off the ground
- One complete gait cycle includes both a stance phase and a swing phase for one limb
Clinical and Performance Applications
Video analysis of the gait cycle helps:
- Identify asymmetries between left and right limbs
- Detect abnormal movement patterns or compensations
- Assess rehabilitation progress after injury
- Evaluate footwear and orthotic effectiveness
- Optimize running technique and efficiency
The duration of the gait cycle varies with walking or running speed, with faster speeds generally resulting in shorter cycle times. Stride length, cadence, and the relative timing of each phase all provide valuable information about movement quality and efficiency.