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Y balance test kitTM (YBT) is used to measure dynamic balance. YBT is an instrumented version of the Star Excursion Balance test that has Anterior (A), Posteromedial (PM), and Posterolateral (PL) directions. PURPOSE: To determine electromyographic (EMG) activity of the trunk and lower extremity (LE) muscles during YBT performance. METHODS: Surface EMG was collected on 10 males and 10 females healthy adults for the erector spinae (ES), external oblique (EOB), and rectus abdominis (RA) for both ipsilateral (i) and contralateral (c) sides of the stance leg, and gluteus medius (GMED), gluteus maximus (GMAX), Rectus Femoris (RF), Vastus Lateralis (VL), Vastus Medialis (VM), Medial Hamstrings (MH), Biceps Femoris (BF), Anterior Tibialis (AT), and Medial Gastrocnemius (MG) muscles of the stance leg during the performance of the YBT. A 2-way repeated measures analysis of variance (ANOVA) was used to determine the interaction between percentage maximal voluntary isometric contraction and reach directions of the YBT. Separate 1-way repeated measures ANOVA for each muscle was performed to compare the normalized EMG values of the same muscle across the 3 reach directions. Pairwise comparisons were performed using the Sidak post hoc test at an alpha level of .05. RESULTS: The 2-way repeated measures ANOVA with 2 repeated factors, muscle (15 levels) and reach direction (3 levels) interaction was statistically significant (P


Poster presented at the 2021 Annual Meeting of the American College of Sports Medicine held online June 1-5, 2021.


  1. Ruffe NJ,Sorce SR, Rosenthal MD, Rauh MJ. Lower quarter and upper quarter Y balance tests as predictors of running related injuries in high school cross country runners. Int J Sports Phys Ther. 2019;14(5):695.
  2. Ganesh GS, Chhabra D, Pattnaik M, Mohanty P, Patel R, Mrityunjay K. Effect of trunk muscles training using a star excursion balance test grid on strength, endurance and disability in persons with chronic low back pain. J. Back.Musculoskelet Rehabil. 2015;28(3):521 530.

  3. Bhanot K, Kaur N, Brody LT, Bridges J, Berry DC, and Ode JJ. Hip and trunk muscle activity during the Star Excursion Balance Test in healthy adults. J Sport Rehabil 28: 682 691, 2019.