If you a fixated about gaining a six pack look, in every exercise plan you need to incorporate as many different muscles from around the body in one exercise. The truth behind fast effective fitness training is that if you want to get the best abs, and you want to lose weight then you need to use an effective training method.  

The best method of training is to recruit as many muscle fibres as possible using heavy loads like with training methods like one rep max, squats, dead lifts,burpee's and chin ups.  To make sure that you are Increasing your hormone growth and testosterone levels you need to be using compound exercising than focuses on training different methods and muscle systems at the same time. Some easy rules for this type of training is that you always include lower and upper body muscles in every exercise.

Below find and example of a standard resistance band compound exercise.

Frontal shoulder raises & step back lunge - intermediate, advanced

Muscles; Shoulders, deltoids, gluts, quads & calves

1.Start in a standing position with your feet shoulder width apart and your knees relaxed. One foot on resistance cord.

2.Take the handles, palms facing down, elbows stay slightly bent. Whilst Stepping back into Lunge and extend arms forwards away from body at the same time. 3.Pause momentarily at this top position. Slowly lower back to the starting position as you lower step into lunge..