be at full strength
To be at the maximum strength, capacity, or level of power or ability. It took a while, but I'm finally back at full strength after my injury. Now that the army is at full strength, our enemies don't stand a chance against us.
be below full strength
To not be at the maximum strength, capacity, or level of power or ability. I've been below full strength ever since my injury. If our army is below full strength, we don't stand a chance against our enemies.