Background: Unstable surface-based core training can significantly enhance core strength, but no studies have compared the effects of balance pad- and sling-assisted exercises.
Objects: To study the effects of unstable surface-based balance pad- and sling-assisted core strength exercises on muscle activity.
Methods: Twenty male students aged 20–25 years participated in this study. The effects of three types of core strength exercises, performed with a sling or balance pad, on the activities of three muscles, i.e., the right musculus obliquus externus abdominis (EO), right erector spinae (ES), and right gluteus maximus (GM), were examined.
Results: 1) In the glute bridge exercise, the percentage of maximum voluntary contraction of the EO, ES, and GM were significantly different between the balance pad- and sling-assisted exercises. The relative contribution of the ES and GM activities to all muscle activity were not significantly different between the two training types, whereas that for EO showed a significant difference. 2) There was no significant difference in the percentage value of maximum voluntary contraction (%MVC) among the EO, ES, and GM during the “leg-lifting with flat support”exercise, and there were no significant difference in the relative contributions between the two training types. 3) In the “side bridge leg separation exercise”, the %MVC of the ES, EO, and GM were significantly different between the two training types.
Conclusion: Sling training for core muscles was generally better than balance pad assist training. The majority of physiotherapy patients require core training. Our results could guide physiotherapists in the choice of targeted exercises for these patients.

INTRODUCTION
MATERIALS AND METHODS
    1. Participants
    2. Instrumentation
    3. Procedures
    4. Data analysis
RESULTS
DISCUSSION
CONCLUSIONS
CONFLICTS OF INTEREST
AUTHOR CONTRIBUTIONS
REFERENCES

• Yaoyao Liu(Department of Physical Therapy, Graduate School of Inje University)
• Won-gyu Yoo(Department of Physical Therapy, College of Health Care Medical Science and Engineering, Inje University, Gimhae) Corresponding Author
• Su-Jung Kim(KEMA Healing Center, Busan, Korea)