After going full time I started having knee problems. Turns out it was from the short RV step you have to turn your foot to the side when you step out.
I added the step stool but the second step is the same to narrow to step straight out on it. I've tried everything and this is what I finally found to work with an RV....cinder blocks!
I ended up going to the box store and getting cinder blocks. They line up just perfectly. WHAT a difference. Within a week both my knees where back to normal. I don't leave home without them.
Here is the cinder blocks that line up perfectly with the step stool allowing the second step to be wide enough to step on straight forward no twisting your foot as you step off.
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When I stay any longer than 2 weeks in a CG I add a second step of the flat 1/2 cinder blocks. The white tape is so I can see the step off at night. Room for my foot to land straight no matter how I leave the RV!
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At a buck apiece I just leave them at the CG when I move on. Well worth the $$ not to have my knees all swollen and avoid costly surgery!! Just wished I figured this all out earlier in my RV'ing! :C