August 7 — in history

  • Today In Sports History August 7th 2007: Barry Bonds Becomes The Home Run King

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    On August 7th 2007, Barry Bonds broke the all time home run record passing Hank Aaron as the all time home run king. Now, this moment of course doesn’t come without controversy. Barry Bonds was involved in the Balco scandal which linked him to PED’s. Many until today still believe that Hank Aaron is the real home run king.

    @BarryBonds

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    Analysis of Barry Bonds’ Record-Breaking Home Run

    An analysis is presented of the trajectory of the home run by Barry Bonds in August 2007 that broke Hank Aaron’s career home run record.

     

    Introduction

    Barry Bonds broke Hank Aaron’s record for career home runs when he hit his 756th home run on August 7, 2007 (video). A brief analysis is presented here of the trajectory of the home run. The picture below was taken close to the moment of impact.

    The data for this analysis come from two sources. First, the initial part of the trajectory was established from an analysis of the video provided by the PITCHf/x tracking cameras. These cameras provide precise information on the trajectory of pitched baseballs but can also be used to provide information on batted baseballs within their limited field of view. Second, the endpoint of the trajectory was provided by Greg Rybarczyk of hittrackeronline.com, who provided precise information on the location the landing point and the time of flight. As we shall see, if both the initial and final parts of the trajectory are known well, it is possible to put very tight constraints on what happens in between.

     

    The PITCHf/x Tracking Data

    These data consist of seven points at 1/60-second time intervales starting approximately 1/30-sec after contact. Each point consists of a time t and the (x,y,z) coordinates in the so-called Global Coordinate System (GCS). The GCS has its origin (0,0,0) at the corner of home plate. The y axis extends along the catcher-pitcher line, the x axis is the horizontal line perpendicular to the catcher-pitcher line, with the positive direction pointing to the catcher’s right, and the z axis points vertically upward. The figure to the right shows a bird’s-eye view of the coordinate system. The coordinates of these points were determined by manually locating the location of the baseball in pixel coordinates in each frame for each of the two tracking cameras. One camera is located on the first-base side, high above and looking downward. The other camera is located at a comparable position on the third-base side. Using the known camera calibration, these coordinates determine a so-called line of position (LOP), which is a line connecting a known reference point on the camera to the baseball. The coordinates of the intersection of the LOP’s for the two cameras is the actual location of the baseball in the GCS. It is estimated that the position of the baseball is determined to a precision of approximately 1 inch. The seven frames covered the first 20 ft (horizontal) of the trajectory, with a height above home plate in the range 4-12 ft.

     

    The HITTRACKER Data

    These data consist of a single datum which comes from the observation of where the home run landed and the total time of flight. According to Greg Rybarczyk, the ball landed at the GCS coordinates (x,y,z)=(103.7,416.3,12.17), with all distances in feet. The total time of flight from contact to landing was determined to be 5.12 sec by playing back the broadcast video and counting frames.

     

    The Home Run Trajectory

    The trajectory of any fly ball can be calculated given the initial conditions (location, velocity, and spin) and a model for the forces acting on the ball. These forces include gravity, air resistance, and the Magnus force on a spinning baseball. For the present calculation, the prescriptions of Adair1 and Sawicki et al.2 were used for the air resistance and Magnus force, respectively. With these assumptions, the full trajectory can be calculated for given initial conditions. The latter are adjusted in a least-squares fitting procedure to provide a best fit to the eight tracking points (seven from PITCHf/x and one from HITTRACKER). A total of 8 parameters were adjusted: the three initial positions of the coordinates x0, y0, z0; the initial velocity v0, elevation angle θ0, and fan angle φ0; and the amount of backspin and sidespin, ωb and ωs, respectively. Here θ0 is the angle above the horizontal and φ0 is angle the initial trajectory makes with the y axis when projected onto the horizontal plane. The sign convention is such that a ball hit toward first-base, second-base, or third-base correspond to φ0 = 45, 0, or -45 degrees, respectively. The fitted parameters are given in Table I and the best-fit trajectory is shown in Figures 2 and 3. The fitted trajectory has an root-mean-square (rms) deviation from the data of only 1.2 inches. Note that the spin of the baseball is not actually measured but is inferred from the tracking data within the context of the model used for the Magnus force.

     

     

     

    parameter fitted value ± uncertainty
    x0 -0.23 ± 0.09 ft
    y0 1.02 ± 0.03 ft
    z0 2.51 ± 0.09 ft
    v0 112.4 ± 0.3 mph
    θ0 27.0 ± 0.3 deg
    φ0 16.0 ± 0.4 deg
    ωb 1186 ± 71 rpm
    ωs 189 ± 40 rpm
    Table I. Fitted parameters for the home run trajectory.

     

    Figure 2. The home run trajectory for Bonds’ 756th home run, plotted as height above vs. horizontal distance from home plate. The red points (seven near the beginnning and one near the end) are the actual data used to constrain the trajectory. The blue dots indicate 0.5-sec time markers. The initial slope of this curve is the tangent of the elevation angle θ0. From this trajectory, we estimate that the baseball would have traversed a total horizontal distance of 442 ft. before returning to home-plate level had it not hit something else first. Given the precise measurement of both the location where the ball struck and the time of flight, this distance is almost insensitive to the model used for the air resistance and Magnus force. The maximum height of the trajectory is about 92 ft.

    Figure 3. The home run trajectory for Bonds’ 756th home run, plotted as deviation from the catcher-pitcher line vs. the horizontal distance from home plate. The red points (seven near the beginnning and one near the end) are the actual data used to constrain the trajectory. The blue dots indicate 0.5-sec time markers. The initial slope of this curve is the sine of the fan angle φ0. The ball starts out on a trajectory 15 deg to the right of straightaway centerfield, then curves slightly towards centerfield (i.e., the slope gets slightly smaller) as a result of the sidespin.


    Barry Bonds

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    Barry Bonds
    Barry Bonds 2006-05-08.jpg
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    Bonds in 2006
    Left fielder
    Born: July 24, 1964 (age 57)
    Riverside, California
    Batted: Left Threw: Left
    MLB debut
    May 30, 1986, for the Pittsburgh Pirates
    Last MLB appearance
    September 26, 2007, for the San Francisco Giants
    MLB statistics
    Batting average .298
    Home runs 762
    Hits 2,935
    Runs batted in 1,996
    Stolen bases 514
    Teams
    Career highlights and awards

    MLB records

    • 762 career home runs
    • 73 home runs, single season
    • 2,558 career bases on balls
    • 232 bases on balls, single season
    • .609 on-base percentage, single season
    • .863 slugging percentage, single season
    Medals
    Baseball
    Representing
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    United States
    Amateur World Series
    Bronze medal – third place
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    1984 Cuba Team

    Barry Lamar Bonds (born July 24, 1964) is an American former professional baseball left fielder who played 22 seasons in Major League Baseball (MLB). Bonds was a member of the Pittsburgh Pirates from 1986 to 1992 and the San Francisco Giants from 1993 to 2007. He is considered to be one of the greatest baseball players of all time.

    Recognized as an all-around player, Bonds received a record seven NL MVP awards and 12 Silver Slugger awards, along with 14 All-Star selections. He holds many MLB hitting records, including most career home runs (762), most home runs in a single season (73, set in 2001), and most career walks. Bonds led MLB in on-base plus slugging six times and placed within the top five hitters in 12 of his 17 qualifying seasons. For his defensive play in the outfield, he won eight Gold Glove awards. He also stole 514 bases, becoming the first and only MLB player to date with at least 500 home runs and 500 stolen bases. Bonds is ranked second in career Wins Above Replacement among all major league position players by both Fangraphs and Baseball-Reference.com, behind only Babe Ruth.

    Barry Bonds hits his 756th career home run, breaking Hank

  • Bonds breaks Aaron’s record with No. 756 – YouTube

    https://www.youtube.com/watch?v=cL3vNXIsEPM

    Jul 24, 2014 · 8/7/07: Barry Bonds breaks Hank Aaron’s all-time record with home run No. 756 off Mike Bacsik in the fifth inning

  • Barry Bonds: 10 years after 756th home run, record remains …

    https://www.si.com/mlb/2017/08/07/barry-bonds-756…

    Aug 07, 2017 · Commissioner Bud Selig didn’t bother watching Barry Bonds hit home run number 756 on Aug. 7, 2007. He was too busy, as the devilish scriptwriting gods of baseball would have it, prepping for his..

  • Hill: The man who caught 756, a year later – ESPN Page 2

    www.espn.com/espn/page2/story?page=hill/080815

    Matt Murphy is the lucky man who emerged from a scrum at AT&T Park with Barry Bonds’ record-breaking 756th home run ball.

  • Barry Bonds Breaks All-Time Home Run Record (No. 756 …

    https://www.youtube.com/watch?v=XlEZtIgOQVo

    Oct 02, 2015 · 8/7/07: Barry Bonds breaks Hank Aaron’s all-time record with home run No. 756 off Mike Bacsik in the fifth inningSubscribe to our YouTube channel for the bes…

    • Author: San Francisco Giants
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  • Chasing the Hammer | MLB.com

    mlb.mlb.com/mlb/events/bonds

    Bonds launches No. 756. Barry Bonds becomes MLB’s all-time home run leader with a shot off Mike Bacsik. 400K. • Bonds belts No. 755 400K. • Bonds’ milestone homers 400K. Bonds launches No. 756. Barry Bonds hits a solo shot in the fifth, breaking Hank Aaron’s record. Barry Bonds becomes the …