Let me strong-arm you. I used to think weightlifting would make me bulk up too much because I’m naturally muscular. Wow, was I wrong. I got in the best shape ever by lifting heavy weights. Most trainers told me to do high reps with low weights. But the minute I started doing heavy weights and lower reps I really leaned out. My trainer is not a big dynamo, but he’s helped make me so strong — and at 43, stronger than I’ve ever been. So pick up some weight.