Longitudinal trends in human accuracy: A five-decade analysis (1969–2019) of free-throw shooting in the NBA

Describing, understanding, predicting, and controlling the improvement of athletic performance are pivotal aspects of sport sciences. Longitudinal trends of the achievements of elite performers, mainly in endurance (e.g., cycling, running, skiing, and swimming) and explosive-power (e.g., jumping, throwing, and weightlifting) sports, were examined in a series of studies. One of the observations in these studies was the significant improvement in performance in the above-mentioned sports over the 1960s, 1970s, and 1980s. In addition, several factors that can account for the observed improvements were outlined and discussed in the previous literature. The current study contributes to this line of research by examining the rate of improvement in free-throw (FT) shooting of National Basketball Association (NBA) players over a five-decade period –1969–2019. As opposed to many power and endurance sporting events, FT shooting is a fine-motor task performed in a stable and predicted environment. Based on an analysis of more than 2.6 million FT shots, we found that from 1969 to 2019 the FT shooting accuracy fluctuated at around 75%, but did not show any steady trend of improvement. We discuss this finding from a skill-acquisition perspective.