If you are trying to get lean, and stay lean, strength training is invaluable. It increases the resting metabolic rate, increases power and performance, and it will break the redundancy of constantly running or any other cardiovascular activity.
When you are first attempting to shed pounds and fat you may not want to step on a scale because it will be misleading. As you train with weights your body will pack on some pounds with lean muscle mass as you lose fat. If you notice that you aren’t losing weight, or if you even gain weight after training like a madman, don’t panic. That is probably the reason why.
To lose fat fast and get lean quickly you have to gain muscle and workout at high intensities. Strength training can be done at high intensities if you reduce your rest, increase weight, and increase reps. Circuit training is a good option.
Cardio should absolutely be a part of the workout routine because it will exercise your heart, and it’s easy to make cardio intense enough to burn fat. Doing intervals with sprints is a really efficient fat burner .
At the end of the day, you can quickly lose fat and pounds by doing only cardio. But if you want to stay lean in the long run, then you have to prioritize strength training. Lean muscle mass will give you a hard body and increase your metabolism so that keeping that figure will be easier.