AUTHOR=Facer-Childs Elise, Brandstaetter Roland TITLE=Circadian Phenotype Composition is a Major Predictor of Diurnal Physical Performance in Teams JOURNAL=Frontiers in Neurology VOLUME=6 YEAR=2015 URL=https://www.frontiersin.org/articles/10.3389/fneur.2015.00208 DOI=10.3389/fneur.2015.00208 ISSN=1664-2295 ABSTRACT=Team performance is a complex phenomenon involving numerous influencing factors including physiology, psychology, and management. Biological rhythms and the impact of circadian phenotype have not been studied for their contribution to this array of factors so far despite our knowledge of the circadian regulation of key physiological processes involved in physical and mental performance. This study involved 216 individuals from 12 different teams who were categorized into circadian phenotypes using the novel RBUB chronometric test. The composition of circadian phenotypes within each team was used to model predicted daily team performance profiles based on physical performance tests. Our results show that the composition of circadian phenotypes within teams is variable and unpredictable. Predicted physical peak performance ranged from 1:52 to 8:59 p.m. with performance levels fluctuating by up to 14.88% over the course of the day. The major predictor for peak performance time in the course of a day in a team is the occurrence of late circadian phenotypes. We conclude that circadian phenotype is a performance indicator in teams that allows new insight and a better understanding of team performance variation in the course of a day as often observed in different groupings of individuals.