Your definitely gonna see jumping jacks as, a part of your warm up . I will pay more attention to my knees and. Watch this tutorial video to learn how to properly do jumping jacks! be a placebo unless you have a study to. Jumping Jacks are a great addition to any at home cardio workout. Find out how many reps you should do. Feel confident and joyful all summer long with the help of our complete Bikini Body Program! You can also try doing jumping jacks for 10 minutes, resting for two minutes, then doing them for another 10 minutes. Jumping Jacks Illustrated Exercise Guide Share on Facebook Share. This famed body weight cardio exercise reflects the philosophy of multitasking. When you do jumping jacks, you are moving all the large muscle groups in your body.