Who would have thought you could get such a kick butt work out that actually builds muscle, increases strength, improves cardio and has almost endless variations to keep you from getting board with just these little straps. This forces you to use the whole body, stabilizer muscles and core all together. It is efficient and fun. Hey, I also manage a huge gym and sold fitness equipment in the past for thousands of dollars so I almost hate to say it, but for many people this equipment is all you need.