Balance and Proprioception: Y-Balance Test

The Lower Quarter Y Balance Test, or YBT-LQ, is a simplified and standardised version of the Star Excursion Balance Test using three reach directions: anterior, posteromedial and posterolateral. A systematic review and meta-analysis found the YBT-LQ has evidence for reliability, discriminant validity and predictive validity, although interpretation varies by population and outcome.  

Introduction

The Y Balance Test is widely used in sport, rehabilitation-adjacent exercise monitoring and performance settings because it is quicker and easier to standardise than the full SEBT.

It provides useful information about dynamic balance, reach asymmetry and lower-limb control, but should not be interpreted as a standalone injury screen.

Quick Summary

Test name: Y Balance Test
Common version: Lower Quarter Y Balance Test
Abbreviation: YBT-LQ
Category: Lower-limb dynamic balance
Primary score: Reach distance in three directions
Optional score: Composite score normalised to limb length
Key limitation: Predictive validity is population- and context-dependent.

What Is the Assessment?

The client stands on one leg and reaches the other leg in three directions: anterior, posteromedial and posterolateral. Scores are usually normalised to limb length and may be combined into a composite score.

Why It Is Used

Used to assess dynamic balance, reach asymmetry, lower-limb control, baseline performance and progress over time.

What It Measures

The YBT-LQ may reflect dynamic postural control, hip/knee/ankle coordination, reach capacity, mobility, stance-limb control and confidence under single-leg loading.

Who It Is Used For

Useful for field sport athletes, court sport athletes, runners, military populations, gym clients and lower-limb performance monitoring.

Equipment Required

• Y Balance Test kit or marked floor setup
• Measuring tape or Measurz AR measurement
• Limb-length measurement
• Optional Measurz stopwatch for rest intervals
• Optional Measurz rep counter for trial counting
• Measurz/MAT platform for reach distances, normalised scores and retest data
• MAT strength tools for related lower-limb strength testing

Step-by-Step Protocol

1. Measure limb length.
2. Set up anterior, posteromedial and posterolateral reach directions.
3. Client stands on the test limb.
4. Reaching foot pushes or reaches in the target direction without losing balance.
5. Record best valid reach distance for each direction.
6. Repeat both sides using consistent practice trials.
7. Calculate normalised reach and composite score if required.

Scoring and Interpretation

Record:

• Anterior reach
• Posteromedial reach
• Posterolateral reach
• Limb length
• Normalised reach
• Composite score
• Side-to-side asymmetry
• Invalid trials
• Symptoms

A lower composite score or marked asymmetry may indicate a lower current dynamic balance profile, but should be interpreted with context.

Normative Data, Benchmarks or Reference Values

Normative values vary by age, sex, sport and activity level. Practical normative tables are available for multiple groups, but values must match the protocol and population. A YBT-LQ systematic review found performance differences across populations and noted that predictive validity depends on the specific metric and population studied.  

Practical guidance only:

• Use normalised reach distance.
• Compare left and right.
• Compare with sport/age/sex-specific data where available.
• Use baseline and retest as the main interpretation.

Reliability and Validity

The YBT-LQ systematic review and meta-analysis reported evidence for reliability, discriminant validity and predictive validity, but did not support one universal risk threshold for all groups.  

Common Errors and Limitations

Common errors include poor practice standardisation, stance-foot movement, weight transfer to the reach foot, not normalising to limb length and overusing risk cut-offs outside the tested population.

Practical Applications

The YBT-LQ can help monitor lower-limb dynamic balance, compare sides, track training response and support broader testing batteries that include strength, ROM, hop and outcome measures.

How to Record This in Measurz/MAT

Record side, reach direction, raw distance, limb length, normalised score, composite score, symptoms and retest date. Use Measurz AR measurement for distance and notes for invalid trials.

FAQs

What are the three directions? Anterior, posteromedial and posterolateral.
Should scores be normalised? Yes, to limb length where possible.
Can it predict injury? Some studies suggest associations, but it should not be used alone.
Is it the same as SEBT? It is a simplified, standardised related test.

Key Takeaways

• YBT-LQ is a standardised dynamic balance test.
• Normalisation improves interpretation.
• Predictive validity is context-specific.
• Use with other assessments.
• Measurz can track reach and composite scores.

References

Bulow, A., Anderson, J. E., Leiter, J. R. S., MacDonald, P. B., & Peeler, J. (2021). The modified Star Excursion Balance and Y-Balance Test results differ when assessing physically active healthy adolescent females. International Journal of Sports Physical Therapy.  

Plisky, P., et al. (2021). Systematic review and meta-analysis of the Y-Balance Test Lower Quarter: Reliability, discriminant validity, and predictive validity. International Journal of Sports Physical Therapy, 16(5), 1190–1209. https://doi.org/10.26603/001c.27634