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Modern Techniques for Evaluating Hitting Alan M. Nathan University of Illinois

Modern Techniques for Evaluating Hitting Alan M. Nathan University of Illinois. Batted ball analysis Initial speed and angles Landing point and hang time Swing analysis Bat speed Swing plane Timing “squaring up”. Introductory Remarks. Tradition techniques are “outcome-based”

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Modern Techniques for Evaluating Hitting Alan M. Nathan University of Illinois

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  1. Modern Techniques for Evaluating HittingAlan M. NathanUniversity of Illinois • Batted ball analysis • Initial speed and angles • Landing point and hang time • Swing analysis • Bat speed • Swing plane • Timing • “squaring up”

  2. Introductory Remarks • Tradition techniques are “outcome-based” • BA, SLG, OPS, BABIP, … • Modern techniques are “process-based”, independent of outcome • What constitutes a well-hit ball? • What constitutes a good swing?

  3. Tools for Modern Technique • Baseball Info Solutions (BIS) • Batted ball landing point and hang time • Hitf/x • Initial batted ball speed and angles • TrackMan or Fieldf/x • All of the above (i.e., full trajectory) • Physics • Relating batted ball to swing parameters

  4. Example: HITf/x Analysis See Mike Fast, BPro, Nov. 16 & 22, 2011

  5. What Constitutes “Good Contact”? Hitf/x from April 2009 BABIP • ~50% of balls hit with BBS90 mph are safe hits, regardless of VLA • ~37% of balls hit with BBS 90 mph and 250≤VLA≤350are HR HR

  6. What Constitutes “Good Contact”? Hitf/x from April 2009 BABIP • ~80% of balls hit with 100≤VLA≤150 are safe hits, regardless of BBS • ~68% of balls hit with 100≤VLA≤250 and 60≤BBS≤80 mph are safe hits HR

  7. Potential of These Data • Quantify “good contact” (GC) • Establish outcome-inpependent metrics for hitting based on GC • Investigate relationship between GC and pitching metrics • Small sample size and sustainability • Potential even greater if landing point & hang time are known • Ben Jedlovic’s talk at 2013 SABR Analytics

  8. Example Divide BBS-VLA space into rectangles • For each rectangle, assign a value based on some useful metric • e.g., BA, SLG, Linear Weights, … • For any hitter, weighted average can be computed to arrive at overall metric

  9. Landing Point/Hang Time(image courtesy of BIS) Small horiz speed Large horiz speed

  10. Ex: Two MLB Hitters(images courtesy of BIS) Batter #1 Batter #2

  11. Comparing the two methods using TrackMan data BBS tof:R:bbs R bbs:vla:R

  12. Comparing the two methods using TrackMan data BBS tof:R:bbs R bbs:vla:R

  13. (bbs,vla)  (tof,R)? All stadiums covered stadiums Considerable variation of R for fixed bbs,vla.

  14. Why does initial velocity not determine landing point accurately? • Variation in air density • Easy to control • Variation in wind • Not so easy to control, except for covered • Variation in spin • More in a mintue • Variation in surface properties of ball • A topic of intense interest (to me!)

  15. Related question: Is greater “carry” a skill? • In particular, is ability to put backspin on ball a skill? • With both initial velocity vector and landing point/hang time, we can address this question for individual batters • Related to swing parameters

  16. New Research Project • Can batted ball data determine swing parameters? • A very challenging physics problem • In this talk I will • State the problem • Discuss progress in solving

  17. fan tilt E = offset Bat Swing Parameters • Bat speed determined by pitch and batted ball speed • Fan: timing of swing • Tilt: to swing plane • Offset: “squaring up”

  18. Current State • Bat swing parameters can predict batted ball parameters. • fan+tilt+offset HLA+VLA+spin axis • Can batted ball parameters determine bat swing parameters?

  19. Simple Example:Straight Pitch, RHH, Tilt=00 Fan=150 Fan=00 Fan=-150 E=+1” E=0” E=0 E=-1” 19

  20. Simple Example:Straight Pitch, RHH, Tilt=450 Fan=150 Fan=00 Fan=-150 E=+1” E=0 E=-1” 20

  21. A Brief Aside:Spin of a Batted Baseball normal force friction 2000 fps 120 mph

  22. 00 -450 450 Fly balls break toward foul line LF RF

  23. Effect of tilt on spin axis

  24. Tilt  Balls hit to CF slice RHH LHH

  25. Current State of Affairs Spin axis might be able to determine tilt angle Spin axis can be determined from trajectory hang time backspin lateral deflectionsidespin spin axis ~ tan-1(sidespin/backspin) Work still in progress but It looks promising that HLA+VLA+spin axis fan+tilt+offset

  26. Summary/Outlook • We have some new tools for evaluating batting based on process rather than outcome • Determining swing parameters from batted ball data looks promising but still a work in progress • Progress on both fronts would benefit greatly from existing data that are not readily available

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