Similar Electromyographic Activities of Lower Limbs Between Squatting on a Reebok Core Board and GroundLi, Yongming1; Cao, Chunmei2; Chen, Xiaoping3Journal of Strength & Conditioning Research: May 2013 - Volume 27 - Issue 5 - p 1349–1353 doi: 10.1519/JSC.0b013e318267a5fe Original Research Abstract Author Information Abstract: Li, Y, Cao, C, and Chen, X. Similar electromyographic activities of lower limbs between squatting on a reebok core board and ground. J Strength Cond Res 27(5): 1349–1353, 2013—Reebok Core Boards (RCB) used as a platform in training provide an unstable environment for resistance training. The objective of this study was to examine the effect of unstable surface on muscle electromyographic (EMG) activities during a deep squat task. Thirteen male subjects participated in the study. Electromyographic activities of soleus (SO), vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), gluteus maximus (GMa), gluteus medius (GMe), and upper lumbar erector spinae (ULES) muscles were collected when subjects were performing a deep squat task on a RCB and ground with different weight loads (body weight, 30%RM (repetition maximum) and 60%RM). No significant difference was observed for all muscle EMG between unstable and stable surface during all weight load conditions (p > 0.05). Muscle EMG significantly increased when the weight load increased (p < 0.05). Similar muscle activities were observed when subjects performed a deep squat task on a stable and unstable surface. Simply applying unstable surface might not provide extra stimulation to the superficial muscles during squatting in resistance-trained students. 1Institute of Movement and Training Science II, Faculty of Sport Science, University of Leipzig, Leipzig, Germany 2Department of Physical Education, Tsinghua University, Beijing, China 3Faculty of Sport Science, Ningbo University, Ningbo, China Address correspondence to Yongming Li, firstname.lastname@example.org. Copyright © 2013 by the National Strength & Conditioning Association.