Resistance training (colloquially "weight lifting") is the most efficient tool for body transformation, regardless of gender, age and goals. Whether you want to

Resistance training (colloquially "weight lifting") is the most efficient tool for body transformation, regardless of gender, age and goals. Whether you want to gain muscle or lose fat, it gets you there in the shortest amount of time (both time in the gym, and calendar time). Once you reach your goals, feel free to switch to a more diverse regimen for maintenance. EDIT: 15-rep sets is not "bodybuilder's workout". It's a waste of time. Either lift heavy, or go outside and do cardio. That in-between never-never land should be avoided. EDIT2: Let me restate this. Above a certain set length, weight lifting ceases to train strength - which is its main external goal. The opinions differ, but in general the limit is estimated around 10 ... 12: if your set is that long, the weight you're using is too easy. Use heavier loads, so that you cannot do such long sets. In practice, the longest sets that are profitable are 8 reps. If you're worried about strain and injuries, do warm-ups with 67% the working load - a short set of a few reps at 67%, maybe repeated once if things are really sketchy with your joints, should be enough. Then lift with a powerful, but fluid and controlled motion. Never jerk the weight.