Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2009 Effect of Surface Stability on Core Muscle Activity During Dynamic Resistance Exercises Brennan J Thompson Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Exercise Science Commons Recommended Citation Thompson, Brennan J., "Effect of Surface Stability on Core Muscle Activity During Dynamic Resistance Exercises" (2009) All Graduate Theses and Dissertations 240 https://digitalcommons.usu.edu/etd/240 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU For more information, please contact digitalcommons@usu.edu EFFECT OF SURFACE STABILITY ON CORE MUSCLE ACTIVITY DURING DYNAMIC RESISTANCE EXERCISES by Brennan J Thompson A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Health, Physical Education and Recreation Approved: Eadric Bressel, Ed.D Major Professor _ Edward M Heath, Ph.D Committee Member Brian T Larsen, D.P.T., M.S Committee Member _ Byron R Burnham, Ed.D Dean of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2008 ii Copyright © Brennan Thompson 2008 All Rights Reserved iii ABSTRACT Effect of Surface Stability on Core Muscle Activity During Dynamic Resistance Exercises by Brennan J Thompson, Master of Science Utah State University, 2008 Major Professor: Eadric Bressel, Ed.D Department: Health, Physical Education and Recreation The purpose of this study was to compare core muscle activity during resistance exercises performed on stable ground versus an unstable surface and to examine whether lifting at different relative intensities affects core muscle activity levels Twelve trained men performed four different movements including the deadlift, back squat, military press, and curl Surface electromyography (EMG) was utilized to assess the activity of the rectus abdominis, external oblique, transversus abdominis, and erector spinae muscles Participants performed each movement under three separate conditions including standing on stable ground with 50% of their one repetition maximum (1-RM), standing on a BOSU balance trainer with 50% of their 1-RM and, standing on stable ground with 75% of their 1-RM The following muscles exhibited greater activity during the 75% 1-RM condition than all other conditions: the transversus abdominis (TA) and external oblique (EO) muscles during the deadlift; the rectus abdominis (RA) during the squat; the TA, RA, and EO during the press, and TA and erector spinae (ES) during the iv curl The ES muscle during the press movement and EO during the squat movement were more active during the BOSU 50% 1-RM condition than the stable 50% 1-RM condition Healthy individuals might consider performing the military press, curl, squat and deadlift movements with higher intensity resistances while standing on stable ground to incur higher widespread muscle activity of the core region (61 pages) v ACKNOWLEDGMENTS I would like to offer a special thanks to my committee for the time and effort they have put forth in helping this endeavor come to fruition I would also like to sincerely thank Dr Bressel for his unwavering dedication and enthusiasm and countless hours spent reading, editing, commenting, and preparing for my thesis project Much appreciation is felt from the efforts of Dr Heath and Brian Larsen in providing feedback and willingness to cooperate with time constraints I would also like to thank all of my friends and colleagues for their knowledge and sense of humor I have grown to thoroughly enjoy and appreciate the associations and cohesion that is felt at the HPER department with both colleagues and faculty I would like to thank my family; my parents for their support and good example, by living the life the way that most would say life should be lived, but few have the capacity or courage to actually achieve; to my brothers for many priceless memories and adventures; to my sister, brother-in-law, and nephews whom give encouragement, hope, joy, and substance to a wandering nomad A personal and uncompromising thanks is expressed to my grandparents Educational pursuit and achievement are the best thanks I can render to Harold and Elda Thompson; who had the patience, courage, foresight, and love to support and believe in a stubborn young man that had all but given up on graduating from high school Brennan J Thompson vi CONTENTS Page ABSTRACT iii ACKNOWLEDGMENTS v CONTENTS vi LIST OF TABLES viii LIST OF FIGURES ix CHAPTER I INTRODUCTION .1 II LITERATURE REVIEW Definition of the Core Region Purpose and Rationale of Core Training Unstable Surface Training .9 Summary 15 III METHODS 16 Participants 16 Procedures 16 EMG Analysis 20 Statistical Analysis .20 IV RESULTS 21 Deadlift 22 Squat 24 Press .26 Curl 27 V DISCUSSION 29 Deadlift 29 Squat 30 Press .32 Curl 33 vii Future Research .35 Summary 36 Limitations 38 Conclusions 40 REFERENCES 42 APPENDICES 47 Appendix A: Informed Consent .48 Appendix B: PAR-Q viii LIST OF TABLES Table Page Muscle Activation for Stable vs Unstable Surfaces 11 Muscle Activity (NEMG; µ, SD) for Movements, Muscles, and Conditions .21 ix LIST OF FIGURES Figure Page NEMG Amplitude of Core Muscle Activity Expressed During the Deadlift Movement 23 NEMG Amplitude of ES Muscle Activity During the Deadlift Movement 24 NEMG Amplitude of Core Muscle Activity During the Squat Movement 25 NEMG of ES Muscle Activity During the Squat Movement 25 NEMG Amplitude of Core Muscle Activity During the Press Movement 26 NEMG Amplitude of Core Muscle Activity During the Curl Movement .28 38 are perceived to be a higher risk than stable surface training) more empirical results are needed to confirm that unstable surface training is worthwhile Limitations The following limitations may have an effect on interpreting the results of the study: • The cadence of this study was set at a 4-1-4 (4 s eccentric, s pause at the bottom and s concentric) to help control for the effects of momentum and the possible decrease in EMG activity that may result due to less force required of the muscles to overcome inertia This cadence is an unnaturally slow tempo for performing resistance exercises A particular difficulty with this tempo is overcoming inertia resulting from transitioning from the eccentric to concentric motion An evaluation of more natural tempos and the effects on EMG activity is warranted in this area of research • The amount of resistance utilized for the BOSU 50% 1-RM was calculated from the stable 1-RM A true 50% 1-RM on the BOSU would be different than compared to the stable surface because the unstable condition may elicit a decrease in total force production The loads used for the BOSU 50% 1-RM condition would have likely been higher than 50% 1-RM for that condition A 1RM for the unstable surface would yield more accurate resistances, however due to the nature of unstable surface training, a 1-RM test increases the hazard and reduces the safety for the participants 39 • One limitation of EMG collection is the amount of adipose tissue between the muscles and the surface electrodes Body composition was not taken of the participants and therefore means and SDs are unavailable for assessing possible levels of error in EMG readings This data would be valuable for this type of research in the future as it may give insight to outliers and magnitude of potential sources of error in EMG readings • All 12 participants were recruited from a university population and so the results may only be applicable to college-aged males • One limitation of EMG includes cross-talk (electrodes placed over one muscle picking up activity from other muscles) Preparations were made as to minimize the effects of this factor by using previously identified locations for placement of electrodes over the muscles, which fortunately for this study kept the electrodes an acceptable distance apart • Increased fatigue may have an effect on EMG readings An attempt was made to reduce factors that effect fatigue including performing only three repetitions of each movement Although the movements were counterbalanced, fatigue may have been a factor towards the end of the routine as many reps were required due to the multiple conditions and movements A solution for this may be to divide the routine into a two day occurrence, thus, reducing the number of repetitions performed during each occasion 40 Conclusions Within the limitations of the study the following conclusions may be made: • Intensity of load may be more important for recruitment of TA and EO muscles during the deadlift movement than increasing the level of instability Activation of the RA during deadlift movement may be achieved by either increasing the level of intensity or increasing instability • Performing the squat movement at 75% 1-RM on a stable surface may be more effective at recruiting the RA and TA than increasing instability If recruitment of the EO muscle is desired, the squat movement may be performed with either increased level of intensity or on an increased level of instability • The ES muscle may be equally activated independent of intensity of load (at a minimum level of 50% 1-RM) or level of instability for the squat and deadlift movements Either the squat or deadlift movements may be performed on an unstable surface or with higher levels of resistance for recruitment of the ES muscle • The military press may be more effective for recruitment of the TA, RA, and EO muscles when performed with higher levels of resistance (at least 75% 1-RM) as opposed to increased levels of instability • When performing the curl movement, if ES and TA activation are desired then the level of resistance is more influential than the level of instability at increasing muscle activity If EO activation is desired than the curl movement may be performed with either higher levels of resistance or increased level of instability 41 RA activation is insignificantly changed independent of level of resistance or level of stability for the curl movement 42 REFERENCES Arokoski, P J., Valta, T., Airaksinen, O., & Kankaanpaa, M (2001) Back and abdominal muscle function during stabilization exercises Archives of Physical Medicine and Rehabilitation, 82, 1089-1098 Anderson, K., & Behm, G D (2005) Trunk muscle activity increases with unstable squat movements Canadian Journal of Applied Physiology, 30, 33-45 Baechle, R T & Earle, W R (2000) Essentials of Strength Training and Conditioning Champaign, IL: Human Kinetics Behm, D (1995) Neuromuscular implications and applications of resistance training Journal of Strength and Conditioning Research, 9, 264-274 Behm, G D., Leonard, M A., Young, B W., Bonsey, C A., & MacKinnon, N S (2005) Trunk muscle 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implications for injury and chronic low back pain Clinical Biomechanics, 11, 115 Cholewicki, J & VanVliet, J J (2002) Relative contribution of trunk muscles to the stability of the lumbar spine during isometric exertions Clinical Biomechanics, 17, 99-105 Cholewicki, J., Simons, P A., & Radebold, A (2000) Effects of external trunk loads on lumbar spine stability Journal of Biomechanics, 33, 1377-1385 Cram, J R., Kasman, G S (1998) Introduction to surface electromyography Gaithersburg: Aspen Publication Cressey, M E., West, A C., Tiberio, P D., Kraemer, J W., & Maresh, M C (2007) The effects of ten weeks of lower-body unstable surface training on markers of athletic performance Journal of Strength and Conditioning Research, 21, 561-567 Crisco, J J., & Panjabi, M (1991) The intersegmental and multisegmental muscles of the spine: A biomechanical model comparing lateral stabilizing potential Spine, 7, 793-799 Fredericson, M., & Moore, T (2005) Core stabilization training for middle and longdistance runners New Studies in Athletics, 20, 25-37 44 Gambetta, V., & Clark, M (1999) Hard core training Training and Conditioning, 10, 34-40 Hamlyn, N., Behm G D., & Young, B W (2007) Trunk muscle activation during dynamic weight-training movements and isometric instability activities Journal of Strength and Conditioning Research, 21, 1108-1112 Hedrick, A (2000) Training the trunk for improved athletic performance Strength and Conditioning Journal, 22, 50-61 Hodges, P W, & Richardson, C A (1996) Inefficient muscular stabilization of the lumbar spine associated with low back pain: A motor control evaluation of the transversus abdominis Spine, 21, 2640-2650 Hodges, P W., & Richardson, C A (1999) Altered trunk muscle recruitment in people with low back pain with upper limb movement at different speeds Archives of Physical Medicine and Rehabilitation, 80, 1005-1012 Johnson, P (2002) Training the trunk in the athlete Strength and Conditioning Journal, 24, 52-59 Liemohn, P W., Baumgartner, A T., & Gagnon, H C (2005) Measuring core stability The Journal of Strength and Conditioning Research, 19, 583-586 Luoto, S., Helioraara, M., Hurri, H., & Alaranta, M (1995) Static back endurance and the risk of low back pain Clinical Biomechanics, 10, 323-324 Magnusson, M L., Aleksiev, A., Wilder, D G., Pope, M H., Spratt, K., Lee, S H., et al (1996) Unexpected load and asymmetric posture as etiologic factors in low back pain European Spine Journal, 5, 23-35 45 Marshall, P W., & Murphy, B A (2005) Core stability exercises on and off a swiss ball Archives of Physical Medicine and Rehabilitation, 86, 242-249 Marshall, P W., & Murphy, B A (2006) Increased deltoid and abdominal muscle activity during swiss ball bench press Journal of Strength and Conditioning Research, 20, 745-750 McDonagh, J M., & Davies, T C (1984) Adaptive response of mammalian skeletal muscle to exercise with high loads European Journal Of Applied Physiology And Occupational Physiology, 52, 139-155 McGill, M S (2001) Low back stability: from formal description to issues for performance and rehabilitation Exercise and Sport Sciences Reviews, 29, 26-31 McGill, M S., Grenier, S., Kavcic, N., & Cholewicki, J (2003) Coordination patterns of muscle activity to assure stability of the lumbar spine Journal of Electromyography and Kinesiology, 13, 353-359 Morris M., & Morris, S (2001) Resistaball C.O.R.E Instructor Certification Destin, FL: Resistaball, Inc Nadler, S F., Malanga, G A., Bartoli, L A., Feinberg, J H., Prybicien, M., & Deprince, M (2002) Hip muscle imbalance and low back pain in athletes: influence of core strengthening Medicine and Science in Sports and Exercise, 34, 9-16 Norwood, T J., Anderson, S G., Gaetz, B M., & Twist, W P (2007) Electromyographic activity of the trunk stabilizers during stable and unstable bench press Journal of Strength and Conditioning Research, 21, 343-347 Saal, J A (1990) Dynamic muscular stabilization in the nonoperative treatment of lumbar pain syndromes Orthopaedic Review, 1990, 19, 691-700 46 Sale, D (1988) Neural adaptation to resistance training Medicine and Science in Sports and Exercise, 20, S135-S145 San Francisco Spine Institute (1989) Dynamic Lumbar Stabilization Program San Francisco, CA: San Francisco Spine Institute 47 APPENDICES 48 Appendix A Informed Consent CONSENT TO PARTICIPATE IN RESEARCH Effect of Surface Stability on Trunk Muscle Activity and Muscular Endurance Performance for Common Resistance Exercise Movements You are invited to participate in a research study conducted by Dr Jeffrey M Willardson, Professor in the Kinesiology and Sport Studies Department at Eastern Illinois University You have been invited to participate in this study because you are an experienced male lifter between the ages of 18 and 30 and answered “NO” to all questions on the Physical Activity Readiness Questionnaire (PAR-Q) PURPOSE OF THE STUDY The purpose of this research project will be to compare differences in the activity of different trunk muscles when resistance exercises are performed while standing on stable ground versus standing on a BOSU balance trainer PROCEDURES This study will be carried out over a period of weeks with exercise session per week During weeks and 2, familiarization sessions will take place to allow you to practice the required lifts while standing on stable ground versus standing on the BOSU balance trainer During these sessions, a relatively light resistance will be utilized (i.e 20-60 kg) to ensure your safety During weeks and 4, maximal strength testing will take place on stable ground only This will involve gradually increasing the resistance for each exercise to a level that allows for only a single repetition During weeks and 6, pilot testing will occur that will mimic the procedures conducted during weeks 7, 8, and During week 5, you will practice the resistance exercises with a set percentage (i.e 50% 1-RM) of your maximal strength on both surfaces During Week 6, a single subject will be utilized to standardize the EMG data collection During week 7, you will perform set of repetitions of each exercise while standing on stable ground or standing on the BOSU with 50% of your 1-RM You will also perform set of repetitions of each exercise while standing on stable ground with 85% of your 1-RM Therefore, a total of 12 conditions will be assessed During weeks and 9, you will be tested for the maximal number of repetitions that you can perform with 50% of your 1-RM for each of the four exercises while standing on stable ground versus standing on the BOSU POTENTIAL RISKS AND DISCOMFORTS The possible risks include injury to the low back and knee joints You may experience mild muscle soreness following the workouts However, there will be minimal risk of 49 injury through close supervision of every repetition and a thorough warm-up prior to each testing or exercise session If you feel unable to complete a repetition, or experience discomfort at any time, you will be instructed to give a verbal cue at which time the weight will be removed In case of injury the participant may seek immediate medical care at their own expense at the EIU Student Health Center (581-3014) POTENTIAL BENEFITS TO SUBJECTS The benefits of participation in this research are a greater understanding of how standing on unstable surfaces increases trunk muscle tension CONFIDENTIALITY The results of this research study may be published, but your name or identity will not be used In order to maintain confidentiality, your records will be assigned a code number Further, all data will be kept on a disk in a locked desk, accessible only to Dr Jeffrey M Willardson PARTICIPATION AND WITHDRAWL Your participation in this study is entirely voluntary Please ask questions about anything you not understand, before deciding whether or not to participate If you choose not to participate or to withdraw from the study at any time, there will be no penalty IDENTIFICATION OF INVESTIGATORS I understand that if I have any questions concerning the purposes or the procedures associated with this research project, I may call or write: Dr Jeffrey M Willardson Eastern Illinois University Kinesiology and Sport Studies Department 2506 Lantz Bldg 600 Lincoln Avenue Charleston, Illinois 61920 217.581.7592 RIGHTS OF RESEARCH SUBJECTS If you have any questions or concerns about the treatment of human subjects in this study, you may call or write: Institutional Review Board Eastern Illinois University 600 Lincoln Ave Charleston, IL 61920 Telephone: (217) 581-8576 E-mail: eiuirb@www.eiu.edu 50 You will be given the opportunity to discuss any questions about your rights as a research subject with a member of the IRB The IRB is an independent committee composed of members of the University community, as well as lay members of the community not connected with EIU The IRB has reviewed and approved this study I voluntarily agree to participate in this study I understand that I am free to withdraw my consent and discontinue my participation at any time I have been given a copy of this form Printed Name of Participant _ Signature of Participant Date I, the undersigned, have defined and fully explained the investigation to the above subject Signature of Investigator Date 51 Appendix B PAR-Q PAR-Q & YOU Physical Activity Readiness Questionnaire - PAR-Q (revised 2002) (A Questionnaire for People Aged 15 to 69) Regular physical activity is fun and healthy, and increasingly more people are starting to become more active every day Being more active is very safe for most people However, some people should check with their doctor before they start becoming much more physically active If you are planning to become much more physically active than you are now, start by answering the seven questions in the box below If you are between the ages of 15 and 69, the PAR-Q will tell you if you should check with your doctor before you start If you are over 69 years of age, and you are not used to being very active, check with your doctor Common sense is your best guide when you answer these questions Please read the questions carefully and answer each one honestly: check YES or NO YES NO Has your doctor ever said that you have a heart condition and that you should only physical activity recommended by a doctor? Do you feel pain in your chest when you physical activity? In the past month, have you had chest pain when you were not doing physical activity? Do you lose your balance because of dizziness or you ever lose consciousness? Do you have a bone or joint problem (for example, back, knee or hip) that could be made worse by a change in your physical activity? Is your doctor currently prescribing drugs (for example, water pills) for your blood pressure or heart condition? Do you know of any other reason why you should not physical activity? YES to one or more questions If you answered Talk with your doctor by phone or in person BEFORE you start becoming much more physically active or BEFORE you have a fitness appraisal Tell your doctor about the PAR-Q and which questions you answered YES • You may be able to any activity you want — as long as you start slowly and build up gradually Or, you may need to restrict your activities to those which are safe for you Talk with your doctor about the kinds of activities you wish to participate in and follow his/her advice • Find out which community programs are safe and helpful for you ➔ DELAY BECOMING MUCH MORE ACTIVE: • if you are not feeling well because of a temporary illness such as a cold or a fever – wait until you feel better; or • if you are or may be pregnant – talk to your doctor before you start becoming more active NO to all questions If you answered NO honestly to all PAR-Q questions, you can be reasonably sure that you can: 52 • start becoming much more physically active – begin slowly and build up gradually This is the safest and easiest way to go • take part in a fitness appraisal – this is an excellent way to determine your basic fitness so that you can plan the best way for you to live actively It is also highly recommended that you have your blood pressure evaluated If your reading is over 144/94, talk with your doctor before you start becoming much more physically active PLEASE NOTE: If your health changes so that you then answer YES to any of the above questions, tell your fitness or health professional Ask whether you should change your physical activity plan Informed Use of the PAR-Q: The Canadian Society for Exercise Physiology, Health Canada, and their agents assume no liability for persons who undertake physical activity, and if in doubt after completing this questionnaire, consult your doctor prior to physical activity No changes permitted You are encouraged to photocopy the PAR-Q but only if you use the entire form NOTE: If the PAR-Q is being given to a person before he or she participates in a physical activity program or a fitness appraisal, this section may be used for legal or administrative purposes "I have read, understood and completed this questionnaire Any questions I had were answered to my full satisfaction." NAME SIGNATURE _ DATE SIGNATURE OF PARENT _ WITNESS _ or GUARDIAN (for participants under the age of majority) Note: This physical activity clearance is valid for a maximum of 12 months from the date it is completed and becomes invalid if your condition changes so that you would answer YES to any of the seven questions.HealthCanadaSantéCanada © Canadian Society for Exercise Physiology Supported by: ... Movement 25 NEMG of ES Muscle Activity During the Squat Movement 25 NEMG Amplitude of Core Muscle Activity During the Press Movement 26 NEMG Amplitude of Core Muscle Activity During the Curl.. .EFFECT OF SURFACE STABILITY ON CORE MUSCLE ACTIVITY DURING DYNAMIC RESISTANCE EXERCISES by Brennan J Thompson A thesis submitted in partial fulfillment of the requirements for the degree of. .. amplitude of core muscle activity during the curl movement Horizontal bars indicate significance (p < 0.05) between conditions TA and ES muscle activity was higher during the stable 75% 1-RM condition