Resistance bands are exceptional when it comes to strength training. Unlike weights, they allow muscles engaged to maintain tension throughout a repetitions full range of motion, resulting in a more complete stimulation.
Just like free weights, resistance bands come in a variety of “strengths,” but the difference is you are lifting your own body weight rather than additional weight when you use them. Picking the right resistance band can be as confusing as disarming a bomb (blue one? Green one?). Which color? A general guide is yellow=light resistance (beginner), green=easy resistance (beginner-intermediate), red=medium resistance, blue=heavy resistance, black=hardest resistance. Please note that is a general guide, some manufacturers have opted to go off the reservation and come up with their own color codes so be wary!