Building lean muscle is quite a bit more difficult than just gaining mass all together. Espcially if you have grown used to eating a mass muscle building diet of high calories then you may be in for a shock. In order to build lean muscle and make yourself look better defined you need to cut your calories. In the cutting phase you no longer will you be relying on protein synthesis along, instead you need to cut the body fat percentage down and this means less calories in and more energy expended.
You might think it’s easy just cutting your muscle building diet to slim off that extra weight so you have pure definition. Unfortunately, it is a little more complicated since in order for you to get proper definition you’re going to need to burn a lot more calories then you consume and this means a complete change of workout.
In order for you to maximise your weight loss while maintaining some mass you will want to go all out in cardio with some targeted, mostly body weight only exercises.
The reason we only want to do bodyweight and cardio workouts is that during your rebuilding period we don’t want to cause any injuries while you are simultaneously challenging your body and reducing fat. As such you should be aiming for a low in fat, high in protein (for recovery and any muscle you build on the diet) low calorie diet. In terms of calories you should be looking at least 500 less that you burn, minimum.
Some of the best cardio workouts you can do is interval training, where you switch between jogging, running and walking, without any actual full stops to rest. One of the best cardio workouts for fat loss is jumping rope since it is almost inherently interval based. Another great thing about jumping rope is that works almost all the muscles in the body and encourages repair while not being too strenuous on your joints. On average of about 120 skips a minute you will be looking at around 300 calories burnt per 45 minutes.
The key is that you are challenging your body in different ways so that your body never adapts to the same exercise over and over again.
To summarise: Low calories, cardio workout, stay away from the heavy weights and jumping rope is your friend.