Durham University in UK studied 50 years of data from UK Soccer and 4 Olympic combat sports (Boxing, Taekwondo, Greco-Roman wrestling, and Freestyle wrestling). They find a statistically significant advantage for players wearing red (yeah, yeah...I know Scarlet).
Interesting study and clear evidence we should never wear the black or gray alt-unis ever again...and need to add more scarlet to the away uniforms.
http://community.dur.ac.uk/red.advantage/index.html/wordpress/research/