KINETIC, KINEMATIC, AND ELECTROMYOGRAPHICAL ANALYSIS OF INCLINE AND DECLINE PUSH-UPS WITH DIFFERENT CADENCES By Keke Yang A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Kinesiology 2011 ABSTRACT KINETIC, KINEMATIC, AND ELECTROMYOGRAPHICAL ANALYSIS OF INCLINE AND DECLINE PUSH-UPS WITH DIFFERENT CADENCES By Keke Yang This study evaluated if the incline and decline push-up provided any advantage in weight training and physical therapy when compared to the standard push-up; the effects of different performance cadences were also investigated on the incline, standard, and decline push-up. Specifically, the purposes of this study were to examine, as a result of increased incline and decline angles and performance cadences: a) what are changes in the three maximum right hand forces, represented as a percentage of body weight? b) What are changes in the perpendicular hand force patterns when one switches from the incline push-up to decline push-up? c) Which muscle among the pectoralis major, triceps brachii, deltoid, and upper trapezius is the relatively most active one in a standard push-up, after muscle activities are normalized to the Maximum Voluntary Isometric Contraction (MVIC) test? and d) How do muscle recruitment patterns change from the incline to decline push-up? Twenty four college students and recreational weight trainers (age: 19.8±1.4 yrs; weight: 159.8±26.7 lbs; height: 173.9±9.5 cm) participated in this study. Each participant completed two preliminary phases and a formal testing phase on the same day. The formal testing phase consisted of 15 sets (5 body angles and 3 performance cadences) of push-ups, with 3 repetitions in each set. Research question 1 (RQ 1): There exhibited a linear relationship between the increased incline angle (≅15 to 30 to 45 degrees) and the maximum anterior-posterior force (Fx) and perpendicular force (Fz) experienced at the right hand. The Pearson correlation coefficients for these two maximum forces were near -1 in the incline, standard, and decline push-up. There was no obvious relationship between the incline angle and the maximum medial-lateral force (Fy). RQ 2: The same results were generated for relationships between the increased decline angle (≅15 to 0 to -10 degrees) and the three maximum hand forces. RQ 3: It was unexpected that during a standard push-up with cadence 2 (30 beats/minute), the deltoid muscle, instead of the pectoralis major, was proven to be the relatively most active among the four muscles. RQ 4: When participants switched from the incline to decline push-up, the recruitment patterns of the deltoid and triceps brachii were found to be changed, but that of the pectoralis major and upper trapezius remained the same. RQ 5: In incline, standard, and decline push-ups, a higher performance cadence induced significant changes in the maximum hand forces. RQ 6: Fz patterns had a minor change from the incline to decline push-up. Only the phase during the eccentric period showed a presence of more maximum magnitude. RQ 7: In all three cadences, significant changes were found in the activation level of the four muscles between the incline, standard, and decline pushup. RQ 8: In all push-ups, a higher performance cadence induced statistically significant changes in the muscle activation level. Copyright by KEKE YANG 2011 ACKNOWLEDGEMENTS I would like to express my deepest gratitude to my advisor, Dr. Brown, for his seasoned guidance, continuing encouragement, patience, and great help for my graduate research. As a great mentor and friend, Dr. Brown taught me a lot of things beyond the textbooks and things learned from him would certainly benefit me during my whole life. Thank my beloved husband and parents for their always love, support, patience and dedication in both my life and research work. I am heartily thankful to my committee members, Dr. Branta, Dr. Bush, Dr. Ewing, and Dr. Kagerer, for their help and suggestions during my graduate work. Many thanks to Dr. Liu, Dr. Li, Dr. Power, Dr. Bruenger, Dr. Pfeiffer, Dr. Branta, Dr. Bush, Dr. Eisenmann, and Emily Hill for providing experimental instrumentation and technical help. I am indebted to Dr. Deng, Zhenhua, Ginny, and Siyu, who contributed a lot as my research helpers; Chuntian and Yali’s help of being volunteers in the pilot study is highly appreciated. My great thanks to all the instructors, for letting me make recruitment presentation in their classes; and to all the participants for their cooperation and understanding in the experiment and testing. I want to extend my sincere thanks Jo Ann and Jane for special help on information acquisition. v TABLE OF CONTENTS LIST OF TABLES…………………………………...……………………………….……..viii LIST OF FIGURES…………………………………………………………………….…….x CHAPTER 1: INTRODUCTION .................................................................................. 1 Introduction to the Push-up Exercise ................................................................... 1 Popularity of the push-up ............................................................................... 1 Two main purposes of performing the push-up .............................................. 2 Specific techniques of performing the push-up .............................................. 3 Muscles and movements involved in the standard, incline, and decline push-up .......................................................................................................... 5 Variants of the standard push-up ................................................................... 8 Incline and decline push-up ........................................................................... 8 Significance of the Problem ............................................................................... 12 Statement of the Problem ................................................................................... 13 Need for the Study ............................................................................................. 14 Research Questions .......................................................................................... 15 Hypotheses ........................................................................................................ 17 Assumptions ...................................................................................................... 18 Definitions .......................................................................................................... 19 CHAPTER 2: LITERATURE REVIEW ...................................................................... 41 Overview of the Push-up .................................................................................... 41 Analysis of Techniques ....................................................................................... 46 Kinetic and kinematic analysis ..................................................................... 47 EMG evaluation ........................................................................................... 53 Other Facts ........................................................................................................ 67 Gender topics .............................................................................................. 67 Injury- and rehabilitation-related topics ........................................................ 68 Relationship and prediction topics ............................................................... 71 CHAPTER 3: METHODS ......................................................................................... 74 Research Design ............................................................................................... 74 Participants ........................................................................................................ 76 Selection Criteria ................................................................................................ 77 Recruitment ........................................................................................................ 77 Sample Size ....................................................................................................... 78 Instrumentation .................................................................................................. 79 vi Force platform .............................................................................................. 79 Electromyography equipment (EMG) ........................................................... 81 Electrogoniometer ........................................................................................ 84 Anthropometer ............................................................................................. 85 Metronome ................................................................................................... 88 Digital level .................................................................................................. 89 Angle adjustment box and performance board ............................................ 91 Maximum Voluntary Isometric Contraction (MVIC) test bench ..................... 94 Testing Procedures ............................................................................................ 96 Phase one: participant information and preparation phase .......................... 99 Phase two: familiarization phase ............................................................... 100 Phase three: performance testing phase ................................................... 107