Split Squat Assessment: how to evaluate a deep lunge step by step

The lunge (split squat) is one of the most commonly used movement patterns in strength and rehab programs, and also one of the quickest to reveal mobility limitations or unilateral control issues. The Split Squat Assessment (deep lunge test) takes advantage of this: in a single position, you can observe hip, knee, and ankle mobility, plus trunk stability in single-leg support.

What does this test measure?

It measures the ability to reach a deep lunge position with good alignment, assessing hip flexion mobility of the rear leg, ankle dorsiflexion of the front leg, and trunk/pelvis control during the descent.

Unlike the FMS In-Line Lunge (performed on a narrow line, in tandem, scored 0-3), the Split Squat Assessment is performed in a more natural lunge stance (feet hip-width apart) and evaluated more descriptively, observing several alignment criteria at once. If you're already familiar with the FMS In-Line Lunge, think of this test as a more "functional" and less standardized version, useful for observing the pattern actually used in the gym.

Equipment needed

• Enough space to take a long step forward
• Optional: mirror or camera to record from the sagittal and frontal planes

Test protocol

1. The subject takes a long step forward, ending in a lunge position with both feet pointing forward, roughly hip-width apart
2. From there, they descend vertically, bending both knees until the back knee approaches the floor, keeping the trunk upright
3. Observe from the sagittal and frontal planes:

- Whether the trunk stays vertical, without leaning forward - Whether the front knee stays aligned over the foot, without collapsing inward (valgus) - Whether the rear hip allows the descent without the pelvis rotating or tilting - Whether the front heel stays planted throughout the descent

1. Repeat with the opposite leg forward and compare

Common mistakes

• Allowing the trunk to lean forward to compensate for limited rear-hip mobility (this often indicates hip flexor tightness)
• Not observing knee valgus from the frontal plane
• Evaluating only one side and not noting the difference between sides

How to interpret the result

Finding	Possible cause
Good alignment, vertical trunk, no compensations	Functional pattern, no relevant limitations detected
Trunk leans forward	Hip flexor mobility limitation on the rear leg
Front knee valgus	Glute medius / hip stability control deficit
Front heel lifts off	Ankle dorsiflexion limitation
Clear asymmetry between sides	A focus area for unilateral corrective work, regardless of whether each side individually "passes"

This test works best as a qualitative and comparative tool (between sides, and over time) rather than as a test with a closed numeric score.

Relationship with other tests

• Ankle mobility and strength test — if the front heel lifts off during this test, it's worth digging deeper here
• Deep Squat Assessment (FMS) — another bilateral squat pattern to compare mobility findings with

Track and follow up

The compensations in this test (trunk lean, valgus, heel lift) are subtle and easy to forget between assessments. With Movalytics you can record observations by side and session, attach reference photos or video, and check whether your mobility and control work is changing the pattern over time.

Frequently asked questions

Is this the same as the FMS In-Line Lunge? Not exactly: they share the same base pattern (lunge), but the In-Line Lunge is performed in tandem on a narrow line and scored 0-3 within the FMS, while this test uses a more natural stance and a more descriptive analysis. What should I do if I see knee valgus on both sides? Prioritize hip control work (glute medius, external rotators) before progressing loads in unilateral patterns like the Bulgarian split squat or loaded split squat. Does it help detect ankle limitations? Yes, it's one of the clearest signs: if the front heel lifts off the ground during the descent, it usually indicates a lack of ankle dorsiflexion on that leg.