Abstract Details

Title Declining Plate Discipline during the Major League Baseball Season May Be the Result of Fatigue

Topic Sports Neurology

Presentation(s) P01 - (-)

Poster/Presentation
Number 260

Objective

Background BACKGROUND: Frequent long-distance travel and few off days over several months predispose to fatigue in Major League Baseball. To test our hypothesis, we examined the number of times a batter chose to swing at a pitch outside of the strike zone (a ball), captured by the O-swing% statistic. This statistic, analogous to plate discipline, was chosen because it represents a negative outcome (i.e. swinging at a ball is always a mistake).

Design/Methods DESIGN/METHODS: Using a searchable database (Fangraphs Inc; fangraphs.com), we tracked the frequency of Major League Baseball batters swinging at pitches outside of the strike zone. Records from 2006 to 2011 were compared to those from 2002 to 2005, as stimulant drugs were officially banned and formal testing enacted after 2005. Data were expressed in team-months as the percentage of pitches swung at outside of the strike zone to total number of pitches seen outside the strike zone (O-Swing%).

Results RESULTS: A total of 30 teams were analyzed. There was a linear increase of O-Swing% over time (p <0.0001 for 2006-2011, p=0.0011 for 2002-2005) and the estimated mean slope was 0.59/month for 2006-2011 and 0.20/month for 2002-2005. For example, a team with an O-Swing% of 20.0 in April is predicted to have an O-Swing% of 22.95 by September.

Conclusions CONCLUSIONS: Performance in strike-zone judgment consistently worsened through the season, and the effect increased following a ban on stimulants in 2005. This trend occurred despite potential gains from practice and repetition through the season. The increase in O-Swing% through the year suggests worsening vigilance and judgement, and may represent fatigue effect. Future research related to performance and fatigue appears warranted in Major League Baseball players and those engaged in other professional sports.

Authors/Disclosures
Scott J. Kutscher, MD PRESENTER	Dr. Kutscher has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Jazz Pharmaceuticals.
	No disclosure on file
	No disclosure on file
Raghu P. Upender, MD (Vanderbilt University Medical Center)	No disclosure on file
Beth A. Malow, MD, MS, FAAN (Vanderbilt University, Neurology)	Dr. Malow has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurim Pharmaceuticals. The institution of Dr. Malow has received research support from National Institutes of Health. The institution of Dr. Malow has received research support from Department of Defense. The institution of Dr. Malow has received research support from PCORI.
Irene Malaty, MD, FAAN (University of Florida)	Dr. Malaty has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Abbvie. Dr. Malaty has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Aevum. The institution of Dr. Malaty has received research support from Abbvie. The institution of Dr. Malaty has received research support from Revance. The institution of Dr. Malaty has received research support from Parkinson Foundation. The institution of Dr. Malaty has received research support from SAGE. The institution of Dr. Malaty has received research support from Emalex. The institution of Dr. Malaty has received research support from Acadia. Dr. Malaty has received publishing royalties from a publication relating to health care. Dr. Malaty has received personal compensation in the range of $500-$4,999 for serving as a Speaker & Center of Excellence Director with Parkinson Foundation. Dr. Malaty has a non-compensated relationship as a MAB member & Center of Excellence Directory with Tourette Association of America that is relevant to AAN interests or activities.

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