Gerald T. Mangine1, Jay R. Hoffman, FACSM1, Adam R. Jajtner1, Adam M. Gonzalez1, William P. McCormack1, Adam J. Wells1, Jeremy R. Townsend1, Nadia S. Emerson1, Edward H. Robinson, IV1,
Jose Vazquez2, Napoleon Pichardo2, Maren S. Fragala1, Jeffrey R. Stout, FACSM1.
1Institute
ABSTRACT
BACKGROUND: Fielding performance is difficult to assess, as traditional measures
of fielding percentage (FPCT) and range factor (RF) do not take into account in-game
activity. The ultimate zone rating extrapolation (UZR/150) rates fielding performance
by runs saved or cost within a zone of responsibility, in comparison to the league
average (150 games) for a position. Spring training anthropometric and performance
measures have been previously related to hitting performance, however their
relationships with UZR/150, FPCT, and RF are unknown.
PURPOSE: Examine the relationship between anthropometric and performance
measurements on fielding performance in professional baseball players.
METHODS: Body composition [3-site skinfold (chest, abdomen, and thigh)] and
performance measurements (grip strength, 10-yard sprint, pro-agility, and vertical
jump) were collected during spring training over the course of five seasons (2007-11)
for professional corner infielders (CI; n=17, fielding opportunities=420.7±307.1),
middle infielders (MI; n=14, fielding opportunities=497.3±259.1), and outfielders (OF;
n=16, fielding opportunities=227.9±70.9). The relationships between these data and
regular season (100-opportunity minimum) fielding statistics were examined using
Pearson correlation coefficients and stepwise regression analyses.
RESULTS: Significant correlations were observed between UZR/150 and body mass
(r=0.364, p=0.012), LBM (r=0.396, p=0.006), VJPP (r=0.397, p=0.006)), and VJMP
(r=0.405, p=0.005). Of these variables, stepwise regression indicated VJMP
(R=0.405, SEE=14.441, p=0.005) as the single best predictor for all players, though
the addition of pro-agility performance strengthened (R=0.496, SEE=13.865,
p=0.002) predictive ability by 8.3%. The best predictor for UZR/150 was body mass
for CI (R=0.519, SEE=15.364, p=0.033) and MI (R=0.672, SEE=12.331, p=0.009),
while pro-agility time was the best predictor for OF (R=0.514, SEE=8.850, p=0.042).
Relationships with FPCT and RF varied among all players and position.
CONCLUSIONS: Spring training measurements of VJMP and pro-agility time may
predict the defensive run value of a player over the course of a professional baseball
season.
INTRODUCTION
• Circumstantial variables occurring during a
baseball game will affect a defensive
player’s value according to traditional
measures of fielding performance (i.e.
Fielding Percentage [FPCT] and Range
Factor [RF]).
• The Ultimate Zone Rating extrapolation
(UZR/150) accounts for these variables and
values a fielder in terms of runs stopped
(positive) or allowed (negative) in
comparison to the league average at a
position seen over 150 games7.
• Anthropometric and performance measures
collected during spring training have been
related to hitting performance3, but their
relationships with UZR/150, FPCT, or RF
are unknown.
of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL ; 2Texas Rangers Baseball Club, Arlington, TX.
RESULTS
METHODS
Subjects
• Twenty-two (n=22) professional baseball players from the Texas Rangers
professional baseball organization during the 2007 – 2011 seasons were
examined.
• A minimum of 100 opportunities (i.e. putouts, assists, and errors) per season to
make a defensive play within a defensive category was required.
• Three defensive categories of positions, based upon similar positional demands,
were used for analysis:
• Corner infielders (first basemen and third basemen) (CI; n = 17, innings =
617.5 ± 358, fielding opportunities = 420.7 ± 307.1)
• Middle infielders (second basemen and shortstops) (MI; n = 14, innings =
918.6 ± 474.3, fielding opportunities = 497.3 ± 259.1)
• Outfielders (OF; n = 16, innings = 868.7 ± 220.8, fielding opportunities =
227.9 ± 70.9).
• Pitchers and catchers were excluded from the analysis due to the unique
defensive demands of their respective positions and because they did not
complete the same spring training performance measures.
Table 1. Anthropometric and Performance Comparisons
Age (y)
Height (m)
Body Mass (kg)
Body Fat (%)
LBM (kg)
VJPP (w)
VJMP (w)
10-yard sprint (s)
Pro-Agility (s)
Max. Grip (kg)
FPCT (%)
RF
UZR/150 (runs)
All Players
(n=47)
27.8±3.4
1.85±0.04
96.1±11.0
12.3±2.6
84.1±8.9
9987±558
2428±293
1.55±0.10
4.42±0.18
125.7±25.8
98.2±1.2
4.66±2.54
-1.9±15.6
Corner Infielders Middle Infielders
(n=17)
(n=14)
28.5±3.9
26.5±3.7
1.86±0.04
1.83±0.02
97.4±12.3
89.1±6.2*
13.8±1.8*#
11.4±3.2†
83.8±9.9
78.9±4.1*
9929±576
9686±386*
2423±309
2251±185*
1.6±0.1*
1.54±0.07
4.53±0.14*#
4.38±0.15†
125.6±25.9
121.4±26.4
98.1±1.8
97.9±0.9
6.68±2.95*#
4.85±0.41#†
-7.8±17.4*
-3.6±16
Outfielders
(n=16)
28.2±2.2
1.87±0.06
100.7±10.2#
11.4±2.1†
89.1±8.5#
10311±522#
2589±274#
1.5±0.1†
4.35±0.19†
129.7±26.2
98.5±0.7
2.35±0.27*†
5.7±10†
¶ LBM = Lean Body Mass; VJPP = Vertical Jump Peak Power; VJMP = Vertical Jump Mean Power; FPCT = Fielding Percentage;
RF = Range Factor; UZR = Ultimate Zone Rating.
*Significantly (p<0.05) different from Outfielders.
#Significantly (p<0.05) different from Middle Infielders.
†Significantly (p<0.05) different from Corner Infielders.
Figure 1. The field of play is
broken up into 78 zones of
responsibility used for calculation
of UZR/150. The fourteen furthest
from home plate not included in
the calculation.
PURPOSE
Measures
• De-identified data from required spring training measurements were provided by
the team NSCA certified strength coaches (CSCS) for analysis.
• Anthropometric and Performance variables included:
• Body Composition determined from 3-site (chest, abdomen, and thigh)
skinfold1,4
• Vertical Jump power determined from Harman Formula2
• 10-yard sprint speed and Pro-agility Drill (5 – 10 – 5 sprint)
• Maximal grip strength (Sammons Preston, Bolingbrook, IL, USA)
Table 2. Selected bivariate correlations between fitness components and
measures of fielding performance by defensive category.
Corner
Middle
Outfielders
Infielders
Infielders
Ultimate Zone Rating/150
(r)
(r)
(r)
(r)
Age (yr)
-0.081
-0.045
-0.107
-0.216
Height (m)
-0.069
-0.096
-0.105
-0.269
Weight (kg)
0.364*
0.519*
0.672#
-0.240
Body Fat (%)
0.028
0.310
0.425
-0.449
LBM (kg)
0.396#
0.512*
0.650*
-0.149
VJPP (w)
0.397#
0.440
0.373
0.082
VJMP (w)
0.405#
0.502*
0.507
-0.042
10-yard Sprint (sec)
-0.139
0.048
-0.032
-0.033
Pro-Agility (sec)
-0.287
-0.127
0.034
-0.514*
Max. Grip (kg)
-0.005
-0.003
-0.138
0.022
Fielding Percentage
(r)
(r)
(r)
(r)
Age (yr)
-0.136
-0.512*
0.497
0.070
Height (m)
0.296*
0.413
-0.100
0.159
Weight (kg)
0.168
0.286
-0.138
-0.392
Body Fat (%)
0.045
0.061
0.155
0.062
LBM (kg)
0.160
0.287
-0.294
-0.440
VJPP (w)
0.168
0.268
-0.149
-0.319
VJMP (w)
0.176
0.292
-0.156
-0.364
10-yard Sprint (sec)
-0.171
-0.134
0.022
-0.293
Pro-Agility (sec)
-0.105
-0.235
0.323
-0.188
Max. Grip (kg)
-0.094
-0.002
0.009
-0.698#
Range Factor
(r)
(r)
(r)
(r)
Age (yr)
-0.246
-0.544*
-0.094
-0.284
Height (m)
0.086
0.411
-0.182
-0.254
Weight (kg)
0.050
0.321
0.383
0.219
Body Fat (%)
0.313*
0.125
0.376
-0.428
LBM (kg)
-0.043
0.315
0.267
0.331
VJPP (w)
-0.104
0.252
0.038
0.479
VJMP (w)
-0.048
0.297
0.166
0.400
10-yard Sprint (sec)
0.187
-0.168
-0.493
-0.527*
Pro-Agility (sec)
0.201
-0.251
-0.197
-0.216
Max. Grip (kg)
-0.082
-0.041
-0.401
0.204
†FPCT = Fielding Percentage; RF = Range Factor; UZR/150 = Ultimate Zone Rating per 150 innings;
VJPP = Vertical Jump Peak Power; VJMP = Vertical Jump Mean Power
*p≤0.05
#p≤0.01
All Players
THE SINGLE BEST PREDICTORS
Regression Analysis of the Ultimate Zone Rating/150
All Players: VJMP (R=0.405, SEE=14.441, p=0.005)
•VJMP + Pro-Agility (R=0.496, SEE=13.865, p=0.002) improved
predictive ability by 8.3%.
Infielders: Body Mass (CI: R=0.519, SEE=15.364, p=0.033; MI: R=0.672,
SEE=12.331, p=0.009).
Outfielders: Pro-agility time (R=0.514, SEE=8.850, p=0.042)
Regression Analysis of Fielding Percentage
All players: Height (R=0.296, SEE=0.012, p=0.043)
Corner Infielders: Age (R=0.512, SEE=0.016, p=0.035)
Outfielders: Maximal grip strength (R=0.527, SEE=0.242, p=0.036)
Middle Infielders: None
• Statistical Analysis included:
The purpose of this investigation was to identify
the anthropometric and physiological variables
that may predict fielding performance across
defensive positions in professional baseball.
• One-way analysis of variance (ANOVA) for differences between
defensive categories
• Pearson product moment correlations to examine relationships
between performance data and defensive statistics (FPCT, RF, and
UZR/150) for all players and by defensive category.
• Stepwise regression to determine the contribution of each variable.
Regression Analysis of Range Factor
All players: BF% (R=0.313, SEE=2.441, p=0.032)
•BF% + Age (R=0.469, SEE=2.296, p=0.004) improved predictive ability
by 12.2%.
Corner Infielders: Age (R=0.544, SEE=2.556, p=0.024)
Outfielders: 10-yard sprint time (R=0.527, SEE=0.242, p=0.036)
Middle Infielders: None
SUMMARY & PRACTICAL APPLICATIONS
SUMMARY
• Possessing a greater vertical jump mean power (VJMP) and a lower pro-agility time
are the best predictors of a fielder’s ability to routinely make outs of baseballs hit in
play and save runs from being scored.
• Greater lower-body power may expand the coverage range in which a fielder may
successfully make plays, and be related to greater throwing ability8.
• The predictive ability of pro-agility performance confirms previous research
indicating agility as a desired trait in fielders5, and appears to be most valuable to
outfielders.
• Greater body mass and lean body mass also appeared to be significantly (p<0.05)
correlated with the ability to save runs for infielders. Body fat percentage was not
significantly correlated.
• Lower-body power was not related to elite fielding performance in middle infielders.
This might suggest a minimum power standard required to play shortstop and
second base, which is similar to what is seen as professional baseball players age6.
• The traditional measurements of fielding performance, FPCT and RF, did not
produce consistent results for all players or across positions, which is likely related
to the insensitivity of the two measurements.
PRACTICAL APPLICATIONS
• Athletes and coaches should focus on developing and maintaining agility and power
which appear to be the best predictors of elite baseball fielding performance.
• Body mass appears to be particular y important for infielders
• Pro-agility time was the best predictor for outfielder fielding performance.
• Spring training measurements of LBM, vertical jump power, and pro-agility run may
be the best predictors of season-long value in runs a position player is defensively
worth (UZR/150).
• Strength coaches and team managers may find this information useful in the early
identification of those players who are most capable of contributing to team fielding
performance or the need to improve agility and power.
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