Yeah, you are right. But my ego took a bruising. :-} With the disks, you feel the pull in all directions. Back and side lunges are great. As are squat - slide to the side - squat. You can also do upper body work, core work, etc., not just legs. Balance work is fun, too. You can buy a cheap balance pad or inflatable disk. Work with a medicine ball, too, to make it more challenging. You can make a circuit with weights, stability balls, etc. and go quickly from exercise to exercise. Add some single legs hops in between, or jump squats or jump lunges, etc. to keep your heart rate up. Or "partner train" with your kids. Have them throw a ball to you as you try to catch it at different positions slightly behind you (like the numbers on a clock face). Works your core. Stand back to back and pass ball around you to the person behind you (works your waist). Or sit on a stability ball and crunch up, using your core to help you throw a (non-weighed) ball to your partner. Then crunch back down, then up and catch the ball, then crunch down and up and throw. It can be really fun.