The Russian ruble strengthened Friday to cap off a whipsaw week for the currency. Russia’s native currency gained 4.5% against the dollar, hitting 56.7 and climbing to a high not seen since August 25.The rally came while other global currencies weakened against the dollar, which hit a fresh 20-year high. LoadingSomething is loading.The ruble moved higher on Friday, making it an outlier among other global currencies as they continued to weaken against the unstoppable US dollar. Russia’s native currency gained 4.5% against the dollar, hitting 56.7 and climbing to a high not seen since August 25. The ruble’s performance was also the strongest gain against the euro since mid-July.The ruble edged lower earlier in the week in response to Russia’s mobilization of more troops into Ukraine, while President Vladimir Putin threatened the use of nuclear weapons in the conflict. But the ruble has rebounded to find renewed strength as the currency has done several times this year. Russia implemented strong capital controls immediately following the invasion of Ukraine and sought to control outflows of cash. The ruble has gone from both one of the weakest – and strongest – global currencies this year. Concurrently, the US dollar index hit a fresh 20-year high on Friday in response to more benchmark rate hikes from the Federal Reserve on Wednesday. The dollar typically responds by climbing higher when the central bank raises rates. Growing fears of recession also pushes investors to seek safe haven in dollar-denominated assets. But other currencies have moved lower as the dollar index gains momentum. The British pound hit a 37-year low against the dollar on Friday while the euro fell below $0.98.