Super-strength secrets of the Hollywood hulks
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Robert Downey Jr. -- Tony Star, 'Iron Man' and 'Iron Man 2'( Francois Duhamel / Marvel Studios )
Height: 5' 8½"
Weight: 175 pounds
Heroic secret: Trainer Brad Bose told Us magazine that he helped Downey gain 20 pounds of muscle in a month with a "Rocky IV meets high-tech training" routine, including beating truck tires with a 20-pound sledgehammer and pushing a custom-built wheelbarrow with 700-pound weight stacks around an obstacle course. Downey combined the DIY workouts three days a week with kung fu training three days a week.