Any ideas on creating a firm surface on top of a bed for exercising?

I’d worry more about permanently damaging your own excellent self. I can just see you tumbling off a platform and not being able to get up. I’ve done the can’t-get-up thing and don’t recommend it.

Maybe use a stationary bicycle for the time being (rent one?) for low knee impact?

I wasn’t clear (I knew that i wasn’t being clear enough.) I want to set something up on a pre-existing, sturdy queen-sized bed, which isn’t quite firm enough as is.

The tread mill solves the aerobic parts of the program. I need something for supine stretches and strengthening.

How about laying the plywood on top of the box spring? Take the mattress off for now.

Or put the mattress on top of the plywood. That makes a pretty firm surface. I’ve done that when my back was out.

@Jeruba‘s answer was the one I was going to give.

I’ve used a futon mattress on top of a table before for something similar. It may work with your bed just the same and lend a bit firmer surface. You can usually find them affordably priced, but they are bulky to store afterwards. (an Ikea example)

The other thing that worked OK was a heavy exercise mat, like the ones they put under a treadmill or free weights. Easier on your back and bed than plywood might be, but with a quilt or your pad you mention over the top should be similar to your original setup.

I have an elderly friend ( he’s 85 ). He has had both knees replaced and some work on spinal discs.
He uses a Teeter Hang-up for stretching and getting the load off his back and knees.

@Tropical_Willie That thing looks scary as hell. Like a prison restraint chair or something.

@Tropical_Willie: Jeez. Sold and marketed by orthopedic surgeons looking for new patients?

Another solution is to buy fabric and stuffing and make a pad. Futon pads are too big, in general.

What do you think of this, which I just found?Foam massage table cushion?

Good ideas, everyone. You are stimulating my Google skills.

Well Charlie’s Teeter Hang-up is six years old and he uses it five or six days a week.

@gailcalled – I don’t think that will make your bed much firmer, which seems to be the goal, correct?

Similar pads are used as mattress toppers to make beds seem softer and give you that “wrapped up” feeling of sinking in.