Relationships between National Football League combine performance measures

The purpose of this study was to investigate the relationships between the athletic skills measured at the National Football League (NFL) combine. The combine comprises the following tests: 36.6-m sprint with split times at 9.1 and 18.3 m, vertical and horizontal jumps, 18.3-m shuttle run, 3-cone drill, and 102.1-kg bench press. Draftees to the NFL who participated in the annual combine from 2005 to 2009 were included in the study (n = 1,136). Pearson's (r) correlations were calculated to determine the relationships between the tests, and coefficients of determination (r) were used to determine common variance. The 9.1-, 18.3-, and 36.6-m sprint times are nearly perfectly correlated (r ranges from 0.900 to 0.967) as are the change-of-direction ability tests, 18.3-m shuttle run, and 3-cone drill (r = 0.948), suggesting similar skills are being measured. Performance in both jumping tasks is more strongly associated with longer sprint distances, suggesting mechanisms such as the stretch-shortening cycle may be more important at maximal, or near-maximal, speeds. The correlations between change-of-direction ability and sprinting and jumping are generally much weaker (r ranges from 0.250 to -0.653), suggesting less association and independent motor skills. Although not particularly large correlation coefficients, bench press performance is positively correlated with outcomes in all running drills and inversely correlated with jump abilities, suggesting that in the observed cohort, upper body strength may be of little benefit to these tasks. Incorporation of a nonacceleration influenced (i.e., moving start) measure of maximal speed may be preferred if the intention of a test battery is to measure independent motor skills. Further, when constructing test batteries, either the 18.3-m shuttle or 3-cone drill is likely sufficient as a measure of change-of-direction ability. Test batteries should be constructed to measure independent motor skills.