The Gait Cycle
The Gait Cycle[edit | edit source]
The action of walking may be summarised by the following sequence:[1]
- Registration and activation of the gait command within the central nervous system.
- Transmission of gait signals to the peripheral nervous system.
- Contraction of muscles.
- Generation of forces across joints
- Regulation of joint forces and moments by skeletal segments.
- Generation of ground reaction forces (GRF).
Normal gait consists of two phases: stance phase; swing phase. These phases are further divided into a total of 8 sub-phases.[2] The gait cycle involves a combination of open- and closed-chain activities.[3]
Stance Phase
The stance phase occupies 60% of the total gait cycle, during which some part of the foot is in contact with the ground. It is further divided into five sub-phases:
- Initial contact (heel strike)
- Loading response (foot flat)
- Mid-stance
- Terminal stance (heel off)
- Pre-swing (toe off)
Swing Phase
The swing phase occupies 40% of the total gait cycle [4], during which the foot is not in contact with the ground and the bodyweight is borne by the other leg and foot. It is further divided into three sub-phases:
- Initial swing
- Mid-swing
- Late swing[5]
In a complete two-step cycle both feet are in contact with the ground at the same time for 20% of the total gait cycle, 10%at the beginning of the stance phase and 10% at the end of the stance phase.[2] These are termed 'double-support periods'. The rest of the time is spent in single support, when only one foot is in contact with the ground.
The 90-second video below gives the basics of this cycle:
Breakdown of Gait Cycle Sub-Phases[edit | edit source]
Initial Contact (or Heel Strike) - 0%
The moment the foot touches the ground and begins the first phase of double support.[3] Its function is to establish contact with the ground surface and initiate weight acceptance.
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Neutral, 0° | Concentric to eccentric dorsiflexors |
Knee | 5° flexion | Eccentric extensors |
Hip | 30° flexion | Concentric extensors and eccentric flexors |
Loading Response (or Foot Flat) - 0-10%
Begins with initial contact and continues until the contralateral foot leaves the ground. The foot continues to accept weight and absorb shock by rolling into pronation.[3]
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Rapid plantarflexion to 10° | Eccentric dorsiflexors |
Knee | Flexes to 10-15° | Eccentric extensors and concentric flexors |
Hip | Gradual extension | Concentric extensors |
Midstance - 10-30%
Begins when the contralateral foot leaves the ground and continues until ipsilateral heel lifts off the ground. The body is supported by a single leg and begins to move from force absorption at impact to force propulsion forward.[3]
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Gradual dorsiflexion | Eccentric plantarflexors and concentric dorsiflexors |
Knee | Begins to extend | Concentric extensors |
Hip | Gradual extension | Concentric extensors |
Terminal Stance (or Heel Off) - 30-50%
Begins when the heel leaves the floor and continues until the contralateral foot contacts the ground. In addition to single limb support and stability, this event serves to propel the body forward. Bodyweight is divided over the metatarsal heads.[3]
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Gradual dorsiflexion until a maximum of 10° before beginning to plantarflex | Eccentric plantarflexors, then
concentric plantarflexors |
Knee | Continues extending until a maximum of 5° of flexion before beginning to flex | Concentric extensors, then
eccentric extensors and concentric flexors |
Hip | Extends until a maximum of 10° extension | Eccentric flexors |
Pre-Swing (or Toe Off) - 50-60%
Begins when the contralateral foot contacts the ground and continues until the ipsilateral foot leaves the ground. Provides the final burst of propulsion as the toes leave the ground.[4]
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Begins to plantarflex rapidly before foot leaves the ground | Concentric plantarflexors |
Knee | Begins to flex rapidly | Eccentric extensors |
Hip | Begins to flex before foot leaves the ground | Concentric flexors |
Early Swing - 60-75%
Begins when the foot leaves the ground until it is aligned with the contralateral ankle. This event functions to advance the limb and shorten the limb for foot clearance.
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Continues to plantarflex until a maximum of 20° before
moving back towards a neutral position |
Eccentric dorsiflexors, then
concentric dorsiflexors and eccentric plantarflexors |
Knee | Rapid knee flexion until a maximum of about 60° | Eccentric extensors and concentric flexors |
Hip | Gradually flexes | Concentric flexors |
Mid-Swing - 75-85%
Begins from the ankle and foot alignment and continues until the swing leg tibia is vertical. As in early swing, it functions to advance the limb and shorten the limb for foot clearance.
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Maintains a neutral position | Concentric dorsiflexors |
Knee | Begins to extend | Eccentric flexors |
Hip | Continues to flex until a maximum of just over 30° | Concentric flexors |
Late Swing/Deceleration - 85-100%
Begins when the swing leg tibia is vertical and ends with initial contact. Limb advancement slows in preparation.
Kinematics/Joint Motion | Muscle Action | |
---|---|---|
Ankle | Maintains a neutral position | Concentric dorsiflexors |
Knee | Extends until full extension, and flexes just slightly before initial contact | Eccentric flexors, then concentric flexors |
Hip | Hip remains flexed to around 30 ° | Concentric flexors and eccentric extensors,
then concentric extensors |
Clinical Application[edit | edit source]
Understanding the gait cycle allows for effective gait analysis. When analysing gait, it should be done systematically, looking at each joint separately throughout the entire gait cycle and detecting deviations from normal.[2] Injury or disease can alter any of the sub-phases of the gait cycle, resulting in distinct characteristics of the gait pattern.[7]
References[edit | edit source]
- ↑ Vaughan CL. Theories of bipedal walking: an odyssey. J Biomech 2001;36(2003):513-523.Available fromhttp://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.468.2414&rep=rep1&type=pdf
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Webster JB, Darter BJ. Principles of Normal and Pathologic Gait. Atlas of Orthoses and Assistive Devices [Internet]. 2019 [cited 2022 May 11];49-62.e1. Available from: https://www.sciencedirect.com/science/article/pii/B9780323483230000044
- ↑ 3.0 3.1 3.2 3.3 3.4 Shultz SJ et al. Examination of musculoskeletal injuries. 2nd ed, North Carolina: Human Kinetics, 2005. p55-60.
- ↑ 4.0 4.1 Loudon J, et al. The clinical orthopedic assessment guide. 2nd ed. Kansas: Human Kinetics, 2008. p.395-408.
- ↑ Berger W, et al. Corrective reactions to stumbling in man: neuronal co-ordination of bilateral leg activity during gait. J Physiol 1984;357: 109-125.
- ↑ Nicole Comninellis The Gait Cycle Animation Available from https://www.youtube.com/watch?time_continue=35&v=DP5-um6SvQI
- ↑ Shah K, Solan M, Dawe E. The gait cycle and its variations with disease and injury. Orthopaedics and Trauma [Internet]. 2020 Jun [cited 2022 May 12];34(3):153–60. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1877132720300397