Pelvic Drop (Contralateral)

Why this matters

Single-leg stance is the entire reason running differs from walking — at every moment one leg is bearing the body and the other is in the air. The gluteus medius on the stance side is what holds the pelvis level while the swing leg sweeps through. When the glute medius can't generate enough force, the unsupported (contralateral) side of the pelvis drops — known as the Trendelenburg sign.

A 1–3° drop is normal and expected. A drop of 10°+ means the hip stabilisers are failing under load, and the body compensates by adducting the stance-leg femur (knee falls inward = valgus) and laterally flexing the trunk (shoulders shift toward the stance side). That cascade is one of the most reliable injury setups in distance running — it loads the IT band, the patellofemoral joint, and the medial tibia simultaneously.

What good looks like

The hip line stays close to horizontal, with maybe 1–3° drop on the swing side at mid-stance. The shoulders stay level. The stance-side knee tracks straight over the foot without falling inward.

Common faults

• >10° drop — Trendelenburg pattern. Usually paired with knee valgus and trunk lean toward the stance side. The whole upper body cants over to compensate.
• Hip hike (drop on the stance side instead of the swing side) — much rarer; usually a leg-length compensation or a habit pattern. Indicates the swing leg can't clear the ground at the body's natural pelvic height.

Coaching cues

• "Hips level." Combined with mirror feedback during slower-paced strides.
• Strength: side-lying clams, hip airplane drills, weighted side-planks all build gluteus medius capacity.

Related measurements

• Knee Adduction — almost always shifts toward valgus when pelvic drop is excessive.
• Pronation — the downstream consequence; with the hip dropping, the foot has to pronate further to keep the centre of mass over the foot.