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The gait cycle and pathological gait
A normal gait cycle is about 60% stance and about 40% swing, with double support that shortens as walking gets faster and disappears in running; most pathological gaits compensate for weakness of one muscle, which can be identified by the phase in which the deviation appears.
Why it matters in the exam
Stance phases: initial contact, loading response, midstance, terminal stance and pre-swing; swing phases: initial, mid and terminal swing. Double support occurs twice in the cycle (at the start and end of stance) and together makes up about 20% of the cycle at normal speed. The centre of gravity lies just in front of the second sacral vertebra, moves up and down about 5 cm — highest at midstance and lowest in double support — and also moves side to side. Walking is most economical at the person's self-selected speed.
Muscle action: at loading response the ankle dorsiflexors and the quadriceps work eccentrically (lengthening) to brake; at midstance the calf muscles work eccentrically and control tibial advance; at terminal stance they push forward; at terminal swing the hamstrings decelerate the shank. In eccentric contraction the muscle produces more force for less energy, but it is linked with more delayed muscle soreness. Tests of muscle shortening: Thomas (hip flexion contracture), Ely (rectus femoris tightness — lying prone, knee flexion lifts the pelvis) and Ober (iliotibial band).
Pathological gaits: Trendelenburg — weakness of the hip abductor (gluteus medius, superior gluteal nerve): the pelvis drops on the opposite side while standing on the weak leg, and in compensation the trunk leans towards the weak side. Gluteus maximus weakness — the trunk is thrown backwards at initial contact. Quadriceps weakness — forward trunk lean, pushing the knee with a hand and knee hyperextension. Foot drop (deep peroneal nerve or L5) — a "steppage" gait with high knee lift. Antalgic gait — short stance on the painful leg. Hemiplegia — circumduction of the leg. Diplegic CP — a "scissor" gait (spastic adductors) or "crouch" — excessive hip and knee flexion and ankle dorsiflexion in stance, usually with tight hamstrings and weak calf muscles. "Waddling" — bilateral proximal weakness, as in muscular dystrophy.
Key points
- Stance about 60%, swing about 40%, double support about 20%.
- Centre of gravity in front of S2, moving about 5 cm up and down.
- Trendelenburg — gluteus medius; pelvis drops on the opposite side.
- Steppage — foot drop; crouch — CP.
- Thomas, Ely and Ober for tightness tests.
Summary table
| Gait | Muscle or nerve | Sign |
|---|---|---|
| Trendelenburg | Gluteus medius (superior gluteal) | Pelvis drops on the opposite side; compensation — trunk to the weak side |
| Gluteus maximus | Inferior gluteal | Trunk thrown back at initial contact |
| Quadriceps weakness | Femoral nerve, L3–L4 | Trunk forward, knee hyperextension, hand pushing the knee |
| Steppage | Deep peroneal, L5 | High knee lift, foot "slaps" |
| Crouch | Tight hamstrings, weak calf muscles | Hip and knee flexion and dorsiflexion in stance |
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Sources
- Perry and Burnfield: Gait Analysis — Normal and Pathological Function, 2nd edition (2010) — Phases of gait and muscle action
- Braddom's Physical Medicine and Rehabilitation, 6th edition (2021) — Gait Analysis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.