Foul Tip Impacts to Catchers’ in the American League East: A Study of Head Impacts to Catchers by Graham Connell Tebbit A thesis submitted in conformity with the requirements for the degree of Master of Science Graduate Department of Exercise Sciences University of Toronto © Copyright by Graham Connell Tebbit 2020 Foul Tip Impacts to Catchers’ Masks American League East: A Study of Head Impacts to Catchers Graham Connell Tebbit Master of Science Graduate Department of Exercise Sciences University of Toronto 2020 Abstract Purpose: To observe and describe foul tip impacts (FTIs) experienced by MLB catchers and to examine if batting performance was affected by FTIs. Method: Retrospective data analysis was conducted to examine FTIs in games (n= 648) observed using MLB TV. Descriptive statistics, incidence of, and absolute risk for FTIs were calculated. Mixed effects models were used to explore the association between FTIs and catchers’ batting performance. Results: 172 FTIs ranged in speeds (76.7-100.3mph) with 74% reaching 90mph or greater. There were 17.52 FTIs per 10,000 pitches thrown and 17 games with >1 FTI. FTIs varied between catchers (range: 0-32 FTIs). Neither FTI frequency nor speed predicted catchers’ batting performance. Contribution: Described the characteristics and descriptive statistics of FTIs across four MLB teams. Catchers experienced many FTIs at speeds which caused concussion cited in previous research. These findings highlight the need for future research to explore the conditions surrounding FTIs and sports medical management practices. ii Acknowledgments I would like to express my sincere appreciation to my supervisor, Dr. Lynda Mainwaring, for the opportunity to pursue a Master of Science degree. Your kindness, patience and wisdom have been invaluable in my pursuit of a research topic about which I am passionate. Under your tutelage, I have learned that success can only be achieved through persistence and devotion to my craft – with some focused, creative thinking, of course. To my lab, you showed me what it means to be hardworking and diligent researchers. Your mentorship helped me grow, not only as a student but as a person, as well. Thank you for the lessons you taught me and the good memories we shared. I would also like to thank Alex Stringer for all his help and guidance that strengthened the statistical analysis of my data. I would also like to thank my committee for “fielding” all of my questions over the last few years. Dr. Michael Hutchison, you taught me how to critically analyze the literature in your Neurorehabilitation and Exercise class which dramatically shifted the way I interpreted information. Dr. Doug Richards, your breadth of knowledge is astonishing, and I have learned much through our discussions. All your insight and guidance set me on a path to create the thesis it is today. To my parents, Dave Tebbit and Debra Powell, words cannot convey what your tireless support and unconditional love has meant to me throughout this journey. You have always believed in me, through the highs and lows, which is all a son truly needs to know while in pursuit of his goals and dreams. iii Table of Contents Acknowledgments.......................................................................................................................... iii Table of Contents ........................................................................................................................... iv List of Tables ............................................................................................................................... viii List of Figures ................................................................................................................................ ix List of Appendices ...........................................................................................................................x Chapter 1: Introduction ...............................................................................................................1 1.1 Current Knowledge Gaps .....................................................................................................3 Chapter 2: Review of Literature ..................................................................................................6 2.1 Head Impacts .......................................................................................................................6 2.1.1 Baseball ....................................................................................................................8 2.1.2 Subconcussive Impacts ............................................................................................9 2.1.3 Potential Consequences .........................................................................................10 2.1.4 Experimental Modeling of Mask Impacts..............................................................12 2.2 Performance in Sport, Baseball and Head Impacts ............................................................14 2.2.1 Sports .....................................................................................................................14 2.2.2 Baseball Performance ............................................................................................16 2.2.3 Visual Acuity .........................................................................................................17 2.2.4 Vestibulo-Ocular Functioning ...............................................................................17 2.2.5 Attention ................................................................................................................18 2.2.6 Reaction Time ........................................................................................................19 Chapter 3: Method.....................................................................................................................23 3.1 Operational Definitions ......................................................................................................23 3.1.1 Athlete Exposure ....................................................................................................23 3.1.2 Incidence of Catcher FTIs ......................................................................................23 3.1.3 Absolute Risk of >1 FTI in a Game .......................................................................24 iv 3.1.4 Pitch Speed of FTIs ................................................................................................24 3.1.5 On-Field Medical Attention ...................................................................................25 3.1.6 Plate appearance (PA) ............................................................................................25 3.1.7 At-bat (AB) ............................................................................................................25 3.1.8 Hit ..........................................................................................................................25 3.1.9 Batting Performance ..............................................................................................26 3.1.10 Expected-Weighted On-Base Average ..................................................................26 3.1.11 Slugging Percentage...............................................................................................27 3.1.12 Strikeout Rate.........................................................................................................27 3.2 Pilot Study ..........................................................................................................................27 3.2.1 Results ....................................................................................................................28 3.3 Purpose ...............................................................................................................................29 3.4 Research Questions ............................................................................................................29 3.5 Objectives ..........................................................................................................................29 3.6 Hypotheses .........................................................................................................................30 3.6.1 Hypothesis 1...........................................................................................................30 3.6.2 Hypothesis 2...........................................................................................................31 3.7 Sample................................................................................................................................31 3.8 Inclusion Criteria ...............................................................................................................32 3.9 Data Collection ..................................................................................................................32 3.9.1 Procedure ...............................................................................................................32 3.9.2 MLB TV.................................................................................................................32 3.9.3 Observation ............................................................................................................33 3.9.4 Baseball Savant and Statcast ..................................................................................34 3.9.5 Batting Performance Statistics