Effects of Static, Stationary, and Traveling Trunk Exercises on Muscle Activation Darien T. Pyka, Pablo B. Costa*, Jared W. Coburn, Lee E. Brown Department of Kinesiology, California State University, Fullerton, 800 N. State College Blvd. USA Corresponding Author: Pablo B. Costa, E-mail: pcosta@fullerton.edu INTRODUCTION The advancement in research and application of trunk ex- ercises has beneited therapists, trainers, and coaches to improve sports performance, reduce injury risk, and in reha- bilitation of their athletes or patients (McGill, 2010; Wheel- er, 2015). Research has shown the most effective and safest method to train the trunk is a stabilization exercise, where a neutral spine is maintained against a load (Mendrin, Lynn, Grifith-Merritt, & Noffal, 2016). This is due to increased knowledge that the most common function of the trunk is to prevent motion rather than initiate movement, and the trunk muscles should be trained as stabilizers rather than prime movers (McGill, 2010). McGill (2010) describes a stabilization exercise as any exercise that challenges the spine stability while enforcing trunk co-activation patterns that ensure a stable spine (McGill (2010). These exercises consist of holding the spine in a neutral position while the trunk is loaded through different strategies, such as moving upper and lower limbs in several positions or maintaining the pelvis lifted off the loor against gravity in a hold or stationary position (Vera-Garcia, Barbado, & Moya, 2014). A neutral position is referred to as the natural curvature of Published by Australian International Academic Centre PTY.LTD. Copyright (c) the author(s). This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) http://dx.doi.org/10.7575/aiac.ijkss.v.5n.4p.26 the spine and the pelvis without an anterior or posterior tilt (McGill, 2010). It is important to have a relatively strong trunk for re- sistance training and injury prevention (McGill, 2015). In a strongman study, McGill et al. (2009) concluded that strong trunk muscles allow force to dissipate distally to farther areas of the body. A stiff trunk allows power generated from the hips to be transmitted through the torso to the upper body or vice versa. It takes a stiff, stable trunk to allow optimal production, transfer, and control of force during a total body movement (Okada, Huxel, & Nesser, 2011). Hodges and Richardson (1997) found the trunk stabilizers to be activated before any limb movements in a total body exercise, lending the support to the theory that movement control and stabil- ity is developed from the trunk to extremity (Okada et al., 2011). Many movements such as pushing, pulling, lifting, carrying, and rotation use power generated from the hips to perform the exercise (McGill, 2010). If a bend in the spine occurs, known as an “energy leak”, power is compromised (McGill, 2010). Chronic disabling low back pain prevalence is 4.2% in individuals between 24 and 39 years of age and 19.6% in ARTICLE INFO Article history Received: August 11, 2017 Accepted: September 28, 2017 Published: October 31, 2017 Volume: 5 Issue: 4 Conlicts of interest: None Funding: None ABSTRACT Background: A new itness trend incorporates stability exercises that challenges trunk muscles and introduces crawling as an exercise, but has yet to be investigated for muscle activity. Purpose: To compare the effects of static (STA), stationary (STN), and traveling (TRV) trunk exercises on muscle activation of the rectus abdominis, rectus femoris, external oblique, and erector spinae using surface electromyography (EMG). Methods: Seventeen recreationally active women (mean age ± SD = 22.4 ± 2.4 years, body mass 62.9 ± 6.9 kg, height 165.1 ± 5.8 cm) and twenty-three men (23.6 ±3.9 years, 83.2 ±17.1 kg, 177.1 ± 9.1 cm) volunteered to participate in this study. Subjects performed maximal voluntary contractions for normalization of each muscle’s EMG activity. They then performed the three exercises in random order for thirty seconds each with a two-minute rest in between. Results: For the rectus abdominis, STA was signiicantly lower than STN (P = 0.003) and TRV (P = 0.001). For the external oblique, STA was signiicantly lower than STN (P = 0.001) and TRV (P = 0.001) and STN was signiicantly greater than TRV (P = 0.009). For the erector spinae and rectus femoris, STA was signiicantly lower than STN (P = 0.001) and TRV (P = 0.001) Conclusions: There was greater muscle activation in all muscles tested in the stationary and traveling exercises versus the static. Strength and conditioning coaches and allied health professionals could potentially use stationary and traveling forms of trunk stabilization exercises as a viable strategy to increase muscle activation. Key words: Electromyography, Exercise Therapy, Torso, Muscle Contraction, Postural Balance, Back Pain International Journal of Kinesiology & Sports Science ISSN: 2202-946X www.ijkss.aiac.org.au