Inertial Sensor Technology Can Capture Changes in Dynamic Balance Control during the Y Balance Test

Area of Science:

• Biomechanics
• Motor Control
• Sports Medicine

Background:

• The Y Balance Test (YBT) is a common clinical tool for assessing dynamic balance, particularly after lower limb injuries.
• Traditional YBT relies on reach distances, potentially missing crucial information about movement quality and strategy.
• Inertial sensors offer a potential solution for capturing detailed motion data during YBT reach excursions.

Purpose of the Study:

• To compare baseline and fatigued dynamic balance control using both YBT reach distances and 95% ellipsoid volume (95%EV) from an inertial sensor.
• To evaluate the sensitivity of 95%EV in detecting dynamic balance alterations not identified by YBT reach distances.

Main Methods:

• 15 healthy participants performed repeated YBTs before and after a fatiguing Wingate test.
• Dynamic balance was measured using normalized reach distance and 95%EV derived from a lumbar-mounted inertial sensor.
• Intrasession test-retest reliability of the inertial sensor measures was assessed.

Main Results:

• The inertial sensor demonstrated strong intrasession test-retest reliability (ICC 0.76–0.92).
• Both reach distance and 95%EV showed significant changes immediately post-fatigue (p < 0.05).
• Reach distances returned to baseline within 10 minutes, while 95%EV remained significantly elevated for over 20 minutes.

Conclusions:

• An inertial sensor-derived measure (95%EV) effectively quantifies dynamic balance control alterations missed by traditional YBT reach distances.
• The 95%EV measure remained sensitive to fatigue beyond the recovery of reach distances.
• Integrating inertial sensors with the YBT may offer clinicians and researchers an accessible method for detecting subtle changes in motor function.