Cross trainer bro. Don't put your hands up to swing them, but rather place your hands on the handles in the front, so your upper body remains static. Intervals of 30 seconds - eg, 30 seconds sprint, 30 seconds rest. Do it for 20 minutes at the level 10. With bike, just put it on random mode (assuming you have something like LifeFitness bikes at the gym). Go for half hour @ level 12-14. It's enough to even give you a bit of power work out.