The gap regions (505) are left vacant or deposited with second material which is non-reflective, reflective or semi-reflective.

Each alignment device (1) includes a plate member having a surface comprising at least one area of reflective material and at least one area (3, 5) of non-reflective material.

Within a week after the application (typically within less than a few hours after the athletic contest is over) the non-reflective material is removed.