In my opinion, an adjustable set adds so much usefulness to every fitness gym. If you're thinking about investing in fitness bands for the P90X work out, then you might choose to consider the Bodylastics Resistance bands. Hold each end of the resistance band in either of your hands and perform many of the same exercises you would with your dumbbells such as squats, shoulder presses, chest presses, bicep curls, lateral raises, and bent over rows.