It's not an exercise with a lot of movement but try it for 30 seconds and you will be saying "no mas!" Try some wall sits the next time you are working on a spreadsheet or playing a game at home to get your legs strong while you get some work, or gaming, done.
Start next to the wall, bend your knees and put your back on the wall. Your legs should be at 90* at the knee and at your hips if you can. Stay in this position for 30 seconds or as long as you can.