In times of need, football managers often call on supporters to be an "extra man" by turning out in numbers to give players vocal backing. Now, a sports psychologist has found this can really help a team win.

After a series of field-based, controlled experiments assessing the psychological and physiological responses of professional rugby players to different crowd-singing conditions, psychologist Andy Lane has found that player performance can improve by an average of 1.85 percent when they get good vocal backing, reports the Scottish daily Scotsman.

His study shows that the prime time for the supporters to make a difference is when the players are tiring. An easily recognisable chant of support can give the players added stamina, he said.