Now that the quarterback has recovered from his injury, this week the team will be functioning 'at full strength' again. [=the team will have all its players again]
We are negotiating from a 'position of strength'. [=from a strong position; from a position that gives us an advantage]
He didn't mean to knock you down; he just 'doesn't know his own strength'. [=doesn't realize how strong he really is]
(..) This is the time to show them everything. There'll be a bow, make sure you use it. Peeta, you make sure to show your strength. They'll start with District so the two of you will go last. Not on my house to put this... Make sure they remember you! Katniss Everdeen. (..)2012 The Hunger Games