Date of Award

January 2018

Document Type


Degree Name

Master of Science (MS)


Kinesiology & Public Health Education

First Advisor

Grant Tomkinson

Second Advisor

John Fitzgerald


Prenatal testosterone, reflected by digit ratio (2D:4D), is thought to benefit the cardiovascular and musculoskeletal systems and has been shown to benefit long-duration exercise performance, but little is known about the relationship between 2D:4D and short-duration exercise performance (e.g., explosive muscular strength). This study describes the relationship between 2D:4D and lower-body explosive strength, a key factor in successful sports performance, in college athletes. Sixty-one Division I American Football players from a Midwestern U.S. university had their 2D:4D measured digitally and squat jump performance measured using force-platform jumping mechanography. In addition to the primary outcome of jump height, secondary outcomes depicting the execution of the jump were also recorded (peak force, peak Rate of Force Development [RFD], average RFD, starting gradient, and acceleration) from the better of two jumps. Linear relationships between 2D:4D and lower body explosive performance were quantified using partial correlations adjusted for height, mass, age and race. In college football players, 2D:4D was a weak negative correlate of jump height (partial r [95%CI]: −0.26 [−0.48, −0.01]), indicating that athletes with lower 2D:4Ds (i.e., relatively longer 4th digits) tended to jump higher. Jump execution variables were negligible to weak and in the expected direction, although they failed to reach statistical significance. The favorable link between 2D:4D and lower body explosive strength in a homogenous athlete group is the likely result of the long-term organizational benefits of prenatal testosterone. It is possible 2D:4D analyzing can be used as a large scale screening tool for young athletes, allowing parents or future coaches to detect future athletic potential.