The only way to isolate specific back muscles - whether it is upper. or lower back - or make any progress is through the power of the mind-muscle connection.
Lee HaneyCircuit training consists of doing resistant movements combined with an aerobic activity (jogging in place, jump rope, jumping jacks, etc.).
Lee HaneyWhen little old ladies recognize a guy who was Mr. Olympia, that's saying something. That means I've been able to cross lines as far as marketability is concerned.
Lee Haney