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Driveline’s Pitching Research Homepage

Workload Research

Unaccounted Workload Factor: Game-Day Pitch Counts in High School Baseball Pitchers – An Observational Study (Open Access)

Authors: Zaremski, J; Zeppieri, G; Jones, D; Tripp, B; Bruner, M; Vincent, H; Horodyski, M

While pitch counts are an important factor in workload measurement, few studies have gone beyond pitch count to measure workload. This study examined in-game pitches as well as as warm-ups to account for all pitches thrown off a mound the day of a game. This included pitches thrown in a game, pre-game warm-ups, and between inning warm-up pitches.

The researchers observed 34 schools and recorded a total of 13,769 pitches during 115 varsity high school baseball games.

The researchers found that the average number of total pitches thrown during an outing was 42.4% greater than just a standard pitch count.

The mean pitches for live game was 68.9 +- 19.7; bullpen warm-up pitches, 27.2 +- 9.4; and inning warm-up pitches, 23.6 +- 8. This combined for a total of 119.7+-27.8 in 4 innings +- 1.5.

While no pitcher exceeded 105 live-game pitches, the mean of all mound throws was 119.7. Of the outings recorded, 70.4% (81/115) resulted in more than 105 game-day pitches thrown.

While the intensity of throws will change, it would be expected that pre-game and between inning pitches are thrown at lower intensity. This gives a good look at the workload that coaches and players are missing. As mentioned in this study, previous research has suggested that cumulative workload metrics were not predictive of future injury. A reason why that may be is that only counting in-game pitches misses a large number of pre-game and warm-up pitches.

This study did not examine throws warming up before getting on the mound, which would have increased the total number of throws per day. Measuring the acute/chronic workload should be further researched for pitchers, and this paper is a good start at what workload has not been tracked on the mound during game days.

Relationship Between Pitching a Complete Game and Spending Time on the Disabled List for Major League Baseball Pitchers

Authors: Erickson, B; Chalmers, P; Romeo, A; Ahmad, C

This study focused on determining the relationship between pitching a complete game and time on the DL. The hypothesis was that pitchers who threw a complete game would be at increased risk for spending time on the DL.

The researchers concluded that 74% of pitchers who threw a complete game spent time on the Dl, compared to only 20% of the control pitchers. Unfortunately, there is some confusion on how this conclusion was reached.

The pitchers were grouped into those who threw a complete game at some point from 2010-2016 and those who didn’t. 74% comes from of the 501 pitcher seasons of pitchers who pitched a complete game at some point from 2010-2016; 370 (74%) included time on the DL. Because of the wide range of seasons, this doesn’t create a clear causation between the two.

There is also some confusion as to how many pitchers were in each group since “pitcher season” is used in its place. It seems that the groups compared were the percentage of control pitchers who spent time on the DL in a single season, with the percentage of CG pitcher-seasons over the 7-year involving time on the DL. We also don’t have access to the percentage of pitcher seasons for the control groups or the percentage of pitchers for complete-game group.

Lastly, complete games can come with a variety of workloads. A pitcher who throws 105 pitches in 5 innings may be worse than one who throws 105 pitches over 9 innings.

For more information, Zachary Binney has written a more thorough analysis on this study: Article Review: Pitching a Complete Game and DL Risk