Walking is an essential part of life. Walking can be as hard as taking your first step as a child or as easy as a stroll through Henry Cowell Redwoods (a favorite place to walk for my kids and I). Many common phrases utilize walking as the impact statement. Negative: “Take a hike!”
Positive: “My dad walked me down the aisle”
Enticing: “Take a walk on the wild side”
Though provoking: “Walk a mile in my shoes”
The list goes on. The point is that walking is something we do every day and we take it for granted. We assume we will always be able to walk. We assume that if we want to get from point A to point B our legs will get us there without a second thought. In the absence of injury or pathology walking is coordinated, precise, and effortless.
What about for those of us who have pain, joint restriction, arthritis, nerve compression, neurological disease, depression, or poor balance. I doubt everyone feels the same way about gait as the unencumbered.
Walking with the correct form is vital. Let’s take a look at what it means to have “normal” gait.
Gait is a continuous cycle of body support during stance phase and controlled limb advancement during swing phase.
First, let’s define some gait analysis terms.
Stance: The period of the gait cycle when the foot is in contact with the ground
Swing: The period of gait when the foot is not in contact with the ground
Stride: The period from foot contact to the next contact on the same foot
Step: The period from foot contact to the initial contact of the opposite foot
Gaitcycle: Same as the definition for a stride
Phases of Gait
In order to pinpoint phases of gait we need to break down the cycle into recognizable components to determine a pseudo beginning and end. Assessment of a person’s walking pattern by phases allows proper identification of individual joint motions and actions to compare pathological motion to normative values. Normative values come in all kinds of metrics such as muscle activation patterns, joint angles, and internal torques.
For the sake of brevity, we will keep this discussion focused on descriptions of each phase of gait.
"Houston, we have contact."
Initial contact is typically the first phase of gait. It is easy to start the gait analysis at this point since first ground contact is identified with ease. I intentionally did not use the term “heel strike” as is the norm in common practice. Although heel strike is accurate 90% of the time, there may be neurological or range of motion issues that cause a foot flat or forefoot strike walking gait pattern. Therefore we will use the term initial contact for first ground contact. Initial contact is part of weight acceptance which seeks to absorb shock, provide limb stability, and preserve forward progression of movement. The posture of the hip, knee, and foot will determine the loading response pattern of the limb.
Ideally in this phase, initial contact would take place on the heel to set up for what is known as the “heel rocker” which is part of loading response.
Interval of gait: 0-2%
Joint angles at initial contact:
Hip: flexed to 20 degrees
Knee: 0 degrees
*This is a double limb support phase*
The second phase of gait is termed loading response which nicely describes the goal of this phase namely absorb shock. After initial contact, body weight start to progress forward causing a rolling or rocking action at the heel known as the heel rocker. The heel rocker helps to cause flexion at the knee and plantar flexion at the ankle to bring the whole foot in contact with the ground. In this phase knee flexion is essential in order to absorb the shock of the ground reaction force.
Ground reaction force is the force exerted by the ground as a counter force to the force exerted on the ground from weight bearing (For all you physics nerds like myself, Newton’s third law of motion).
Interval of gait: 2-12%
Joint angles at loading response:
Hip: Stays at 20 degrees flexion
Knee: Starts at 0 degrees and flexes to 20 degrees
Ankle: Starts in neutral and plantarflexes to 5 degrees
*Period of double limb support*
Mid stance is the third phase of gait and is the first phase of single limb support. Now the stance limb has total responsibility for supporting body weight, keeping a level pelvis, and staying balanced (tough job!). Mid stance begins as the contralateral (opposite) foot in reference is lifted from the floor and ends when the contralateral tibia is vertical. The end of mid stance coincides with the weight being aligned over the stance limb forefoot. The rocker that takes place in this phase is termed the “ankle rocker”. The rocking takes place as the tibia glides over the talus during forward progression of the limb. Also as mid stance ends the knee and hip begin to extend.
Interval of gait: 12-31%
Joint angles at mid stance:
Hip: Starts at 20 degrees of flexion, ends at neutral
Knee: Starts at 20 degrees of flexion, ends at neutral
Ankle: Starts at 5 degrees of plantarflexion, ends at 5 degrees of dorsiflexion
*First period of single limb support*
Terminal stance is the forth phase of gait and remains a single limb support phase. The purpose of this phase is to progress the body past the supporting foot. The period starts with a heel rise on the stance limb and ends when the contralateral limb makes initial contact. The knee and hip continue to extend in order to provide propulsion.
The rocker in this phase is called the “forefoot rocker”. After the heel lifts off the ground, the weight on the stance limb shifts over the metatarsal heads, and with proper calf, ankle, and foot strength, causes a rocker at the front of the foot.
Interval of gait: 31-50%
Joint angles at terminal stance:
Hip: 20 degrees extension
Ankle: 5-10 degrees dorsiflexion
*period of single limb support*
Pre-swing is the fifth phase of gait and the second period of double limb support. The goal of this phase is to position the limb for swing. This phase starts with initial contact on the contralateral limb and ends with ipsilateral (same side) toe off. This phase can also be termed toe off or weight release.
Interval of gait: 50-62%
Joint angle at pre swing:
Hip: 20 degrees of extension to neutral
Knee: Neutral to 40 degrees of flexion
Ankle: 10 degrees of dorsiflexion to 20 degrees plantarflexion
*Period of double limb support*
Initial swing is the sixth phase of gait and a period of single limb support. This phase begins as the ipsilateral foot is lifted from the floor and ends when the swinging foot is opposite the stance foot. The goal of this phase is swing foot clearance (for balance), and limb advancement to continue forward progression.
Interval of gait: 62-75%
Joint angles at initial swing:
Hip: neutral to 10 degrees of flexion
Knee: 40-60 degrees of flexion
Ankle: 20 degrees of planarflexion to 5 degrees
*Period of single limb support*
Mid swing is the seventh phase of gait and another period of single limb support. This phase begins just as the swing foot crosses the stance foot and ends as the tibia of the swing limb achieves a vertical position. The goals of this phase remain foot clearance and limb advancement.
Interval of gait: 75-87%
Joint angles at mid swing:
Hip: 10 degrees of flexion to 20 degrees
Knee: 60 degrees of flexion to 30 degrees
Ankle: 5 degrees of plantarflexion to neutral
*Period of single limb support*
Terminal swing is the eighth and final phase of the gait cycle. The goal of this phase is to complete limb advancement and prepare the limb for the next stance phase. This phase begins just after tibial vertical and ends when the ipsilateral foot touches the ground.
Interval of gait: 87-100%
Joint angles at terminal swing:
Hip: 20 degrees of flexion
Knee: 30 degrees of flexion to neural
*Period of single limb support*
Altered Gait: Similar to poor car alignment?
Phew! Who knew walking was that detailed. We owe our nervous and musculoskeletal system a great deal of credit for organization all the right joint movements and muscle actions to propel us forward with ease. Walking is a well-timed orchestra of beautiful synchrony. What happens when one of these motions is altered? I like to use the example of getting the alignment corrected on my car. Driving to the auto shop you hear weird noises, your gas mileage is dropping like crazy, and you wear through your tires at rapid pace. Now let’s put that in human terms. While walking you feel aches and pains, you are exhausted from walking the grocery store, and you have developed osteoarthritis at the hips or knees. Sounds pretty similar! Proper alignment and timing is essential to normal gait. If you are having pain with walking or feel drained of energy when strolling your community or home then it is time you visit a gain analysis specialist. Performing a proper assessment takes time and specialized equipment. Be sure to check out specialists in your area that can help improve the way you walk and help you “walk the walk.”
Be sure to check out our state-of-the-art gait analysis evaluation here at Competitive EDGE Physical Therapy in San Jose.
If you would like to speak with a physical therapist or schedule a walking gait assessment please call 408-784-7167 or email Kevin@compedgept.com
Kevin Vandi, DPT, OCS, CSCS
Dr. Vandi is the founder of Competitive EDGE Physical Therapy — with his background in physical therapy, orthopedics, and biomechanics, he is a highly educated, compassionate specialist. Using state-of-the-art motion analysis technology and data-driven methodologies, Kevin has assisted a wide range of clients, from post-surgery patients to youth and professional athletes. When he isn’t busy working or reading research, he spends his time with his wife Chrissy and their five wonderful children, often enjoying the outdoors and staying committed to an active lifestyle.