Y Balance Test (YBT)

The Y Balance Test (YBT) is a standardized and validated tool used to assess functional balance, neuromuscular control, and injury risk in both the lower extremity (LQYBT) and the upper extremity (UQYBT). It is derived from the Star Excursion Balance Test (SEBT) but has simplified execution and improved reliability through the use of a fixed test setup【1】.

YBT is particularly useful in athlete screening, rehabilitation, and return-to-sport evaluations. Its limitation lies in the fact that cut-off values are population- and sport-specific, and test validity depends on standardized equipment and trained examiners.

Lower Quarter Y Balance Test (LQYBT)

The LQYBT evaluates dynamic balance and postural control by having the subject stand on one leg while reaching with the other leg in three directions:

• Anterior (forward)

• Posteromedial (backward, toward midline)

• Posterolateral (backward, outward to the side)

Protocol:

• The subject stands barefoot on a stable platform.

• The free leg is moved in one of the three directions as far as possible in a controlled manner.

• The toes must not touch the floor.

• Maximum controlled reach distance is recorded in centimeters.

• Each direction is tested three times, and the average is used.

Interpretation:

• In American football players, a composite score < 89% of leg length is associated with a 68% probability of injury【2】.

• In male high school basketball players, the cut-off is < 94%【1】.

• An asymmetry greater than 4 cm between limbs in one direction is also considered a risk factor【2】.

Upper Quarter Y Balance Test (UQYBT)

The UQYBT evaluates stability, strength, and control of the shoulder complex. The test is performed in a push-up position, where the subject maintains support with one arm while reaching with the other arm in three different directions.

Clinical uses include:

• Neurological rehabilitation

• Shoulder instability assessments

• Post-operative rehabilitation

• Return-to-play evaluations【3】

Although reliability is good, the research base for UQYBT is still more limited compared to LQYBT.

Reliability and Validity

• LQYBT: ICC values between 0.88–0.99, indicating excellent reliability and low measurement error, even with multiple raters【6】【7】.

• UQYBT: Good inter- and intra-rater reliability reported in specific populations【3】.

• Standardized YBT equipment (YBT Kit) is essential to ensure consistency and accuracy.

YBT in Risk Profiling

The Y Balance Test is often integrated into injury prediction models such as Move2Perform, combining the following factors:

• Previous injury history

• YBT composite score (adjusted for sex and sport)

• Asymmetry measures

• Functional Movement Screen (FMS) score

• Pain reported during testing【7】

This allows categorization into normal, moderate, or high injury risk groups.

Clinical Applications

The YBT is valuable in:

• Prevention: Screening of athletes and high-demand populations.

• Rehabilitation: Monitoring progress after injury or surgery.

• Evaluation: Objective measurement of balance, control, and strength.

• Documentation: Standardized outcomes for clinical and research settings.

Conclusion:The Y Balance Test combines efficiency with high clinical value. It provides important information on balance and neuromuscular control, making it a practical and reliable tool for both sports medicine and general physiotherapy practice.

Sources:

1. Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star excursion balance test som prediktor for skader i underekstremitetene hos basketballspillere i videregående skole. J Orthop Sports Phys Ther. 2006;36(12):911–9.

2. Butler RJ, Lehr ME, Fink ML, Kiesel KB, Plisky PJ. Dynamisk balanseytelse og ikke-kontaktbaserte underekstremitetsskader hos amerikanske fotballspillere. Sports Health. 2013;5:417–22.

3. Westrick RB, Miller JM, Carow SC, Gerber JP. Undersøkelse av Y-Balance Test for vurdering av lukket kinetisk kjede i overekstremitet. IJSPT. 2012;7(2):139–47.

4. PhysioU. Upper Quarter Y-Balance Test [video]. Tilgjengelig fra: https://www.youtube.com/watch?v=Q-iGEVZQHUQ (brukt 05.07.2025)

5. Salmon Bay Physical Therapy. Y Balance Test [video]. Tilgjengelig fra: https://www.youtube.com/watch?v=9RXeq6RZnn4 (brukt 05.07.2025)

6. Plisky PJ, Gorman PP, Butler RJ, Kiesel KB, Underwood FB, Elkins B. Reliabilitet for instrumentert måling av komponenter i star excursion balance test. N Am J Sports Phys Ther. 2009 May;4(2):92–9.

7. Shaffer SW, Teyhen DS, Lorenson CL, Warren RL, Koreerat CM, Straseske CA, Childs JD. Y-Balance Test: en reliabilitetsstudie med flere vurderere. Mil Med. 2013;178(11):1264–70.