I'd say Hoth, but that's purely speculation. He was seemingly very physically strong and in good shape (toned) and was the leader of the Army of Light. He was more of a warrior than a diplomat, and he also believed that he had the ability to singlehandedly defeat the sith, so I'm guessing he was probably the strongest jedi at the time, and that was a very martial era of jedi. I'd even go as far as to speculate that he was on Yoda's level, however I have no real proof until 'Path of Darkness' is released.