Has anyone tried mountain climbing to lose fat -- no, not actually scaling a mountain but the exercise routine. It involves being in an almost plank position and running in place without moving your arms. I do this where I extend my feet up to my abs; however, I have added several variations on this. I use furniture movers under my feet since they glide and it makes it less stressful on my thighs. Seems to be working for me. Thoughts?