Predictors of fielding performance in professional baseball players.
The ultimate zone-rating extrapolation (UZR/150) rates fielding performance by runs saved or cost within a zone of responsibility in comparison with 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 fielding performance measures are unknown.


OBJECTIVE
To examine the relationship between anthropometric and performance measurements on fielding performance in professional baseball players.


METHODS
Body mass, lean body mass (LBM), grip strength, 10-yd sprint, proagility, and vertical-jump mean (VJMP) and peak power (VJPP) were collected during spring training over the course of 5 seasons (2007-2011) 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, while stepwise regression identified the single best predictor of UZR/150.


RESULTS
Significant correlations (P < .05) were observed between UZR/150 and body mass (r = .364), LBM (r = .396), VJPP (r = .397), and VJMP (r = .405). Of these variables, stepwise regression indicated VJMP (R = .405, SEE = 14.441, P = .005) as the single best predictor for all players, although the addition of proagility performance strengthened (R = .496, SEE = 13.865, P = .002) predictive ability by 8.3%. The best predictor for UZR/150 was body mass for CI (R = .519, SEE = 15.364, P = .033) and MI (R = .672, SEE = 12.331, P = .009), while proagility time was the best predictor for OF (R = .514, SEE = 8.850, P = .042).


CONCLUSIONS
Spring-training measurements of VJMP and proagility time may predict the defensive run value of a player over the course of a professional baseball season.
Inst of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL, USA.
Gerald T
GT
Mangine
Jay R
JR
Hoffman
Jose
J
Vazquez
Napoleon
N
Pichardo
Maren S
MS
Fragala
Jeffrey R
JR
Stout
D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001484:Baseball / Q000502:physiology*; D005500:Follow-Up Studies; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D012189:Retrospective Studies; D012420:Running / Q000502:physiology