Final answer:
Coleman Griffith founded the first research laboratory in sport psychology at the University of Illinois, pioneering the scientific study of psychological factors in sports.
Step-by-step explanation:
Coleman Griffith established the first research laboratory in sport psychology at the University of Illinois. This significant advancement laid the groundwork for the systematic study of psychological factors affecting sport performance and the effectiveness of psychological interventions for athletes. The establishment of this lab marked a major milestone in the history of sports psychology, as it was the first of its kind and demonstrated the importance of a scientific approach to studying athletic performance and the mental aspects associated with it.