A total of 55,902 adults participated in the ATUS across the four
years (2003–2006). Of these participants, 8844 individuals (15.8%)
reported at least one bout of recreational sports or exercise on the
previous day. After applying the appropriate population weights,
these individuals represent approximately 44 million non-institutionalized
adults (ages 21+) in the U.S. who engaged in sports and
exercise on any given day during 2003–2006. The demographic
characteristics of the study sample along with weighted population
estimates are shown in Table 1. While the majority of the sample
reported one sports or exercise bout, approximately 23% reported
more than one bout, which contributed to a combined total of 11,555
bouts across all participants.