I have enjoyed reading on a Stairmaster for the last couple of months (after weight-training). I find I can get a high intensity and still read unlike with runn

I have enjoyed reading on a Stairmaster for the last couple of months (after weight-training). I find I can get a high intensity and still read unlike with running, rowing or out of the saddle cycling. Sadly I've found it causes knee pain. This is despite a long history of leg training with no knee issues. It's a real shame but just the old story of not focussing on a single exercise/movement too much I guess.