Schulz, Musa, Staszewski, & Siegler (1994)
Three issues were addressed: 1) peak performance for various baseball skills, 2) individual difference in age-performance curves, and 3) similarities of age-performance curves in athletic domain to other types of domains. The sample consisted of baseball players active in 1965. The players could not be active during a major social event (viz., World War II) or during a period when major changes in the game were introduced (e.g., free agency). A variety of hitter (e.g., average) and pitcher (e.g., era) statistics were analyzed. Peak age of performance was determined for each variable.
Cross-sectional findings can be summarized as follows. First, the peak ages for number of at bats and innings pitched per year were 27. This indicates that peak performance at global level is around 27. Hitting abilities peaked around 27, as did pitching abilities. There were a couple of exceptions. Walks and fielding average peaked around 30, and number of wins and ERA peaked between 28 and 30. Division of the sample into thirds based on lifetime batting average showed that higher performing players peaked later for some of the measures. Additional analyses showed that players who started earlier had longer careers than players who started later, and that better players (i.e., those with higher lifetime batting averages) had longer careers than less skilled players. There was no interaction between starting age and lifetime batting average, indicating that it is not the case that better players have longer careers because they start earlier. Longitudinal analyses produced similar results: better players have longer careers but do not necessarily enter earlier.
Comments and Questions
Perhaps the most interesting result showed that different skills peak at different ages. For example, number of stolen bases and hitters struck out peaked relatively early, while fielding improved into the 30s. Schulz et al. suggest that fielding may be a more knowledge-driven task than stealing bases and striking out hitters, which involve explosive strength. That is, although "reaction time and speed are essential components of good fielding . . ., fielding also requires judgment and knowledge about where to play a particular opponent and about characteristics of different baseball stadiums" (p. 284).