Effect of Box Height on the Muscle Activity during the Bulgarian Split Squat Exercise

Abstract

The purpose of this study was to compare the effects of box height on muscle activity of the ipsilateral erector spinae and gluteus maximus of the dominant leg during the Bulgarian split squat (BSS) exercise. A total of 21 healthy male participants were selected for this study. The participants repeated the Bulgarian split squat three times each on boxes of tibia height and half-tibia height. Surface EMG activity was recorded in the erector spinae and gluteus maximus for five seconds as the knees touched the mat and ascended during the Bulgarian split squat. Maximal voluntary isometric contraction (MVIC) calculated through the manual muscle test was used to normalize EMG activity. A paired sample t-test was conducted to evaluate the changes in the muscle activity of the erector spinae and gluteus maximus between box heights, and a p-value less than 0.05 was considered statistically significant. Although the EMG activity levels of the erector spinae and gluteus maximus were higher during BSS on a box of tibia height, the differences in muscle activity were not statistically significant (p>0.05). The muscle activity levels of the erector spinae and gluteus maximus were lower and similar, respectively, during Bulgarian split squat on a box of half-tibia height compared with a box of tibia height. Thus, it is recommended that BSS be conducted on boxes with shorter heights.