Shields Worn Across the Back

[Bard Heavy-Hands]

My interpretation of the rules leads me to believe that a person may receive the protective benefits of a shield while it is worn across their back, so long as a second shield is not being employed in tandem.

3.5.2.

Shields may be used in any reasonable manner and still be considered a shield.

3.5.3.

Only one shield may be used by a person at a time

[Kyrax]

That is the Belegarth interpretation of those two rules. You can strap it to your arm, on your back or wherever, as long as you only have one shield.