im almost 60 year old . I have be work out since I be in my teens and have continue to engage a lifestyle of eat right and exercise with all type of free weight and machine . I weigh within 10 lb of my high school day and my waist be still a 32 . Shake Weight be another tool and in my opinion a good one . after use it I can feel the muscle pump in my arm , shoulder , chest and back . which mean it do work by stress the muscle group it target . if you think you 'll look like the guy in the demo ad after use it awhile , then you be naive ! if you be so out of shape from not exercise in 20 or 30 year and you think just use the Shake Weight be go to make you physically fit like the guy in the video demo , then you be mistake . if you be just a whiner and complainer who think it be battery power or should be battery power , then you be a nitwit who know nothing about what it take to achieve or stay physically fit ! there 's no such thing as passive exercise that will produce result . try watch `` the biggest loser '' and see how hard they be work and how they be do it . finally , if you be the type of person who believe everything they see , or hear , on tv and infomercial , then you be what we call in the military a `` zipperhead . '' Means you have no brain . physical fitness be never achieve by use just one exercise , device , or technique . but a combination of all sort of exercise , device and technique . Shake Weight be just another tool in the arsenal .