Cross training, does it work?

Cant run at the moment due to sore achilles, likely to miss the next week or two until it subsides enough to start training proper.

I use a stationary bike and a cross trainer in the garage for times when I pick up niggles etc. As this is going to last a little longer and maintaining/improving fitness is important at the moment its important to think about these as proper training sessions rather than ways of avoiding washing the dishes.

How can I compare workouts on either device to say running? What ways of training on these actually add value? My normal method is to cycle/cross train until I collapse in a heap or my eye balls pop, not very scientific

Do some Googleness and there’s lots of info, generally they are thought of highly. I use them quite a bit for general cardio stuff and find them very good.

i struggle to get my HR particularly high on a corss trainer, always feel my legs are giving out way before my heard/lungs are, usualy only hit 170bpm before i cant go any faster.

I went spinning last night, now thats a cardio workout! Joged there an back as well. And by the time i got home i was dizzy/faint/collapsing while grasping at bannanas and hot chocolate (the real suff, cocoa, suggar, milk ) for some calories.