Runner Single-Leg Stability Check
Expose gait imbalances, then strengthen the weak movement pattern
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 98%
Wright explains that running is a single-leg activity: each mile repeats the same loading pattern many times. She demonstrates the Trendelenburg sign by asking Bartlett to perform a single-leg squat while observing whether the pelvis drops and the knee moves inward. A visible difference between sides suggests that hip, glute, or core control may need work, but the episode does not establish that this test alone diagnoses an injury. Wright's decision path is assess the recurring pattern, compare sides, strengthen one side at a time with exercises such as step-ups, step-downs, lunges, or hip hitches, and then retest control. She also recommends motion analysis for predictable recurrent problems. Persistent pain requires professional assessment because tightness, weakness, joint disease, and other causes cannot be distinguished from a podcast demonstration.
Origin
Extracted from The Diary of a CEO. Dr Vonda Wright demonstrates a single-leg Trendelenburg check on Steven Bartlett and links the result to side-specific strengthening.
Core principles
- 01Running repeatedly loads one leg at a time
- 02Pelvic drop and inward knee motion can reveal poor control
- 03Predictable recurring pain warrants movement assessment
- 04Corrective work should train each side independently
How to run it
- 1
Map the Recurrence
Record which side hurts, what activity triggers it, and whether the pattern reliably returns. A predictable pattern is a reason to seek movement assessment.
Pro tip Note changes in speed, distance, surface, and footwear.
Watch out Do not train through acute or worsening pain merely to complete the check.
- 2
Assess Single-Leg Control
With appropriate support or professional supervision, observe a controlled single-leg squat. Look at pelvic level, knee alignment, and balance.
Pro tip Use the same depth and setup on both sides for a fair comparison.
Watch out The Trendelenburg demonstration is a screening observation, not a complete diagnosis.
- 3
Compare Sides
Identify whether one side shows more pelvic drop, inward knee movement, or wobble. Connect the observation to the recurring running pattern cautiously.
Pro tip A physiotherapist can assess other joints and gait factors the simple check misses.
Watch out Do not assume every asymmetry causes injury.
- 4
Train One Side
Use suitable unilateral work such as step-ups, step-downs, lunges, or hip hitches to improve control on the weaker pattern. Begin without load if necessary.
Pro tip Keep the pelvis controlled before adding weight or step height.
Watch out Exercise selection should reflect the actual assessment and symptoms.
- 5
Retest Before Scaling
Repeat the same controlled movement and compare it with the baseline. Increase running or loading only when control and symptoms support progression.
Pro tip Use video from the same angle to compare movement over time.
In the wild
During the demonstration, Bartlett finds one single-leg squat easier than the other and says his left glute is the one that repeatedly gets injured. Wright interprets the observed difference as a reason to strengthen one side at a time, while the exchange remains an informal demonstration rather than a full clinical exam.
→ The recurring complaint is connected to an observable asymmetry and a direction for professional corrective work.
Common mistakes
Running Without Strength Work
Wright says running develops cardiovascular capacity but does not by itself guarantee the hip and glute control needed for repeated single-leg loading.
Treating a Screen as a Diagnosis
A pelvic drop or knee movement can guide further assessment but cannot identify every source of pain.
Correcting Both Sides Identically
The demonstrated imbalance motivates unilateral work that exposes and trains each side separately.
Is it for you?
Best for
It is best used by runners with a qualified physiotherapist or clinician, especially when the same pain or injury repeatedly returns.
Not ideal for
It is not a stand-alone diagnosis and should not replace examination of acute pain, swelling, weakness, or traumatic injury.
From the transcript
“running is a single leg sport”
“this is called the Trendelenburg sign”
“single leg step UPS single leg lunges”
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