If you run regularly, your hips are doing more work than you think. Every stride asks the hip to extend, internally rotate, and decelerate the load coming down through the knee and foot. When the hip can't do that well, the demand gets redistributed — usually to the knee, the low back, or the Achilles. That's where you feel it.

The good news: a handful of validated screens can reveal where your hip is limited, in about ten minutes. Below are five tests I use regularly with runners, with what each one tells you and what to do if it's positive.

1. The Thomas Test (hip extension mobility)

Lie on the edge of a table or bed. Pull one knee to your chest and let the other leg hang off the edge. If the hanging leg's thigh sits above horizontal, your hip flexors are limited on that side — common in runners and desk workers.

Why it matters: running requires repeated hip extension. If the front of your hip is tight, your stride length collapses and the low back compensates. Modified Thomas testing has solid inter-rater reliability when standardized (Harvey, Br J Sports Med, 1998).

2. Single-Leg Squat (hip control)

Stand on one leg. Squat down to about 45–60 degrees of knee bend. Watch in a mirror — does your knee track inward toward the midline? Does your pelvis drop on the unsupported side?

This screen has been used extensively in research on patellofemoral pain and ACL injury risk (Crossley et al., Am J Sports Med, 2011). Knee valgus and pelvic drop on a single-leg squat are both associated with downstream injury risk.

3. Active Straight Leg Raise (posterior chain control)

Lie on your back. Lift one straight leg up. If the heel makes it to 70 degrees or more without bending the knee or pulling the low back into extension, you're in good shape. If it stops at 50 degrees and the opposite hip lifts off the table, that's a hip/hamstring mobility and pelvic control issue.

The active straight leg raise is part of validated screening batteries including the Functional Movement Screen and has reasonable diagnostic value for low back pain in selected populations (Cook et al.).

4. Side-Plank Hold (lateral hip endurance)

Hold a side plank from your knees or feet. Time it. Runners should be able to hold close to 30–45 seconds per side without dropping or shaking heavily.

Why it matters: the gluteus medius and quadratus lumborum stabilize the pelvis during single-leg stance. Weakness here is associated with ITB syndrome, gluteal tendinopathy, and patellofemoral pain (Powers, JOSPT, 2010).

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5. Single-Leg Hop & Land (reactive control)

Hop forward on one leg, land, and hold the landing for two seconds. Look for: a quiet landing, the knee tracking straight, the trunk staying upright, and the foot landing under the hip — not collapsed inward.

Single-leg hop tests are part of the standard return-to-sport battery after ACL reconstruction (Grindem et al., BJSM, 2016) and are useful for runners as a control screen.

“The hip is the upstream joint controlling the knee, foot, and low back.”

What to do with the results

  • Mobility limited (Thomas, ASLR): add daily targeted mobility plus hip-extension strength work like hip thrusts and step-ups.
  • Control issues (single-leg squat, hop): add controlled tempo single-leg work — split squats, step-downs, single-leg deadlifts.
  • Endurance issues (side plank): add lateral hip work — Copenhagen planks, single-leg bridges, banded hip-abduction holds.

These screens aren't diagnoses — they're starting points. If you're running with persistent pain or you've been working on this for weeks without progress, that's the moment to get assessed. See the knee and hip condition pages for related diagnostics.

Bottom line

Most running injuries are downstream symptoms of upstream hip limitations. Five quick screens can tell you where you stand. The work that follows — mobility, control, endurance — is built around the specific deficits these tests reveal.

References

  1. Harvey D. Assessment of the flexibility of elite athletes using the modified Thomas test. Br J Sports Med. 1998;32(1):68–70.
  2. Crossley KM, et al. Performance on the single-leg squat task indicates hip abductor muscle function. Am J Sports Med. 2011;39(4):866–873.
  3. Powers CM. The Influence of Abnormal Hip Mechanics on Knee Injury: A Biomechanical Perspective. J Orthop Sports Phys Ther. 2010;40(2):42–51.
  4. Grindem H, et al. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction. Br J Sports Med. 2016;50(13):804–808.