Do not take my word for it: TRY IT! If you have a smartwatch give my workout a try standing on your feet and then give it a try on your knees. The difference will be significant. On our feet we are very economical: if a move is familiar your body has amazing skills making it efficient. Because most aerobics exercise and even daily activities we conduct on our feet being able to use both legs, we become very economical performing all those tasks. So the above mentioned challenge is not just in your head, it is physiological, too: by having to do something alien, you work harder because your body has not yet had a chance to figure out the most energy saver version of that move. Your body just wants to save energy with every task. By confusing it and trying things differently you make it work. Keep it guessing to see more results! I know not everyone gets wet about calories burnt and energy expenditure of a workout but if you are keen to sculpt your physique and get into fat burning mode: once a week I would recommend trying a hoop workout on the knees. Do not let your body get used to it though! Once a week will do for the desired muscle confusion effect! Experience the increase in your cardiovascular fitness, enjoy how your body gets pushed to the next level of fitness.