I think my son be kid when he say he want one of these thing , but get it anyway . boy be I surprise . all these people that say they think its false advertising be wrong . if you be do it correctly it kick you butt , and bad ! oh yeah im 46 and my shoulder be start to give I fit . after 2 week use the shake weight , my shoulder have quit hurt ! and as far as low-impact go ... yes its very easy on the joint . I will keep use it and just keep increase my time on it ! love it !!!!!! if you not one for hard work , then dont buy it .