Started doing indoor cycling yesterday and gee did it felt disproportionally tiring and unconfortable after I noticed that running for the similar amount of time would have burned 3 to 4 times the amout of calories. I already spent a few days in seat bone pain hell when I first got the bike and this morning's ride left my palms/arms really numb. Thankfully no leg cramps as I worried originally. I guess efficiency and form does matter in sports. Hopefully all these would payoff in the long run.