Gait Analysis

Walking gait is a repeating cycle from one initial contact to the next initial contact of the same foot. Initial contact is usually at the heel, but in pathological gait it may be with the forefoot or a flat foot, so the general term is used. Each cycle divides into a stance phase, when the foot is on the ground, and a swing phase, when it is not, with stance taking roughly sixty per cent and swing forty. Stance subdivides into initial contact, loading response, midstance, terminal stance and pre-swing, and swing into initial, mid and terminal swing. Because both feet are down at the start and end of stance, walking has two periods of double support; these disappear as speed rises and are replaced by a float phase in running. Temporospatial parameters describe the pattern and are easy to measure: cadence, step and stride length, step width, walking speed, and double-support time. Reduced walking speed and increased double-support time are common, non-specific markers that something is wrong.

Recognising the common patterns points quickly to the likely problem. An antalgic gait, the classic limp, shortens the stance phase on the painful side to load it as little as possible, and is seen with most painful MSK conditions. A Trendelenburg gait suggests weak or painful hip abductors: in the uncompensated form the pelvis drops towards the swing side, while a compensated form leans the trunk over the stance hip to keep the pelvis level. It points to, rather than proves, hip abductor dysfunction, since pelvic drop can occur without clear weakness. A high-steppage gait, lifting the leg with exaggerated hip and knee flexion to clear a dropped foot, suggests weak ankle dorsiflexors from a common peroneal nerve or L5 nerve root problem; the two are separated at the ankle, since inversion from tibialis posterior is preserved in an isolated common peroneal palsy but weak in an L5 radiculopathy. Circumduction swings the leg out in an arc to clear a stiff or long limb. Other patterns include the wide-based ataxic gait of cerebellar disease, the stiff scissoring spastic gait, the shuffling Parkinsonian gait, and the waddling gait of proximal weakness.

Observational gait analysis is the everyday tool and the starting point, sitting alongside a targeted examination of joint range, muscle strength, leg length, tone, reflexes, sensation, coordination and balance to localise the problem. The patient walks, and if relevant runs, barefoot and then in their usual footwear, viewed from the front, back and side, while the clinician works through the trunk, pelvis, hip, knee, ankle and foot across stance and swing. Overground walking is assessed first, since treadmill and overground gait are not identical; filming on a phone or tablet and reviewing frame by frame is a widely used two-dimensional video method, with a treadmill an optional addition. When a neurological gait such as foot drop or proximal weakness is found without an obvious mechanical cause, the diagnostic tests are magnetic resonance imaging (MRI) of the lumbar spine or wider neuroaxis and neurophysiology, namely nerve conduction studies (NCS) and electromyography (EMG), to localise the lesion. For biomechanical detail, instrumented methods exist in specialist settings: three-dimensional motion capture is the reference standard for joint kinematics, force plates measure the ground reaction force, plantar pressure mapping shows load distribution under the foot, and wearable sensors allow measurement outside the laboratory. None of these replaces a careful clinical assessment.

Gait analysis does not treat anything by itself; its value is in directing management. Identifying the underlying problem, a painful joint, a weak muscle group or a neurological lesion, points to the right treatment. Footwear and orthotic choices are informed by how the foot loads and by plantar pressure, for example offloading a painful area. Gait retraining, cueing a change in step rate, foot placement or trunk position, can reduce harmful loading in selected runners and is covered in the running biomechanics topic. Targeted rehabilitation follows the confirmed impairment rather than the pattern alone, so hip abductor strengthening is used where abductor weakness is actually demonstrated, and foot drop may need dorsiflexion work or an ankle-foot orthosis. Because some deviations are useful compensations, the aim is to improve pain, safety, efficiency and function rather than to normalise every deviation. Where the cause is neurological or unclear, referral for specialist assessment and instrumented analysis is appropriate.

In rehabilitation, gait analysis provides a baseline and a way to track progress. Recording how a patient moves at the outset, then repeating it as strength, range and control improve, shows whether function and efficiency are improving rather than relying on symptom relief alone. Deviations that persist as pain settles, such as a lingering limp or a dropped pelvis, may flag work still to be done, though some are helpful compensations to preserve rather than correct. For athletes, gait and running assessment is part of return-to-sport decisions, checking that the movement holds up at speed and under load before full training resumes. As with any retraining, changes are practised until they feel natural, and load is progressed gradually.

• •Observational gait analysis is the clinical mainstay, quick and accessible, with reliability improving with a systematic approach and video.
• •Three-dimensional motion capture is the reference standard for joint motion, but cost and complexity keep it in specialist and research settings.
• •Antalgic and Trendelenburg gaits are the key MSK patterns to distinguish: one reflects pain, the other suggests but does not prove hip abductor dysfunction.
• •A new neurological gait, such as foot drop or an ataxic gait, should prompt investigation for an underlying neurological cause.
• •Gait findings guide footwear, orthotic and rehabilitation decisions rather than standing as a diagnosis on their own.

• •Walking gait is stance (about sixty per cent) and swing (about forty per cent), with two periods of double support.
• •Running replaces double support with a float phase, covered in the running biomechanics topic.
• •Antalgic gait shortens stance on the painful side; Trendelenburg gait suggests hip abductor weakness.
• •In foot drop, ankle inversion is preserved in a common peroneal palsy but weak in an L5 radiculopathy.
• •Observational gait analysis is the clinical tool; three-dimensional motion capture is the reference standard.
• •A new neurological gait needs investigation, and if sudden, immediate stroke assessment.