Upper Quarter Y Balance Test: Protocol and Reference Values

The Upper Quarter Y Balance Test (UQYBT) is the upper-body version of the well-known lower-body Y Balance Test, and it's widely used to assess scapular stability and shoulder motor control, especially in throwing sports, rowing, climbing, or any discipline involving quadruped positions or loading through the arms.

It's a dynamic three-direction reach test that combines mobility, strength, and control, all while supporting on a single arm.

What Does This Test Measure?

It measures the ability to maintain stability through one supporting arm while the other performs a maximal reach in three directions (medial, inferolateral, and inferomedial), reflecting neuromuscular control of the shoulder complex and trunk under asymmetric load.

Equipment Needed

• Y Balance Test kit (platform with three graduated sliding tubes) or, alternatively, a tape measure and tape on the floor marking the three directions at 135° from each other
• Stable, non-slip surface

How to Perform the Test

1. The subject gets into a push-up position, with one hand on the platform/central point and the other supporting on the floor
2. Feet are placed shoulder-width apart
3. With the supporting arm, they must push the indicator (or slide the hand) as far as possible in each of the three directions — medial, inferolateral, and inferomedial — while maintaining the push-up position with the opposite arm
4. Perform 3 attempts per direction and side, recording the maximum distance reached (normalized to upper limb length, measured from C7 to the fingertips with the arm extended laterally)
5. Calculate the composite score: sum of the three maximum distances divided by (3 x arm length) x 100

Common Mistakes

• Not keeping the hips and shoulders aligned during the reach (trunk rotation)
• Touching the floor with the reaching hand to brace, instead of just sliding it
• Not normalizing distances by arm length, which invalidates comparisons between individuals

How to Interpret the Results

Measure	Reference
Difference between sides in each direction	Asymmetries greater than 4 cm have been associated with higher shoulder injury risk in some sports studies
Composite score	There's no single universal cutoff; mainly used for intra-subject comparison (pre/post program) and side-to-side comparison
Hip drop or trunk rotation during the reach	Indicates an associated core control deficit, beyond pure shoulder stability

As with many Y Balance tests, the asymmetry between sides is usually more informative than the absolute value.

Related Tests

• Trunk control test — useful if trunk compensations are observed during the Upper Quarter Y Balance Test
• Functional Movement Screen — includes the Trunk Stability Push-Up, another upper-body support pattern that complements this test well

Track and Monitor

With three directions per side and two sides, this test generates 6 measurements per session: tracking them on paper and calculating the composite score by hand is tedious and error-prone. With Movalytics you can record each reach, automatically calculate the composite score, and see at a glance whether the side-to-side asymmetry improves with your program.

Frequently Asked Questions

Do I need the official Y Balance kit? Not essential — you can mark the three directions on the floor with tape and measure with a tape measure, although the kit makes reading and repeatability easier. For which sports is this test most relevant? Especially for sports with repeated upper-body loading: throwing, swimming, climbing, CrossFit, gymnastics, rowing. Does it replace a clinical shoulder assessment? No, it's a screening test for motor control and stability. If pain occurs during the test, refer for a specific assessment before continuing.