Hurt lower back, can't cycle. Best alternative before Crusher?

I’m still trying to do my Crusher training plan, but today I did my workout using my HR zones on a mix of an elliptical and a stair stepper. I’m hoping to be back in the saddle next week, meanwhile I don’t want to miss any workouts. What is the best proxy for biking? Stairstepper? Elliptical? Trailrunning up steep hills?

Call your Doctor or Chiropractor first and foremost to fix yourself first. We can’t give medical advice here on the forum but this is solid coaching advice: get help and never try to train thru it bc you could make it worse.

Hope you heal up soon!