That's probably not true (my title). I'm sure it's much harder. But I did attend an absolutely gruelling class at the gym last night called Basic Training. The trainer was tiny and looked like she had poured fake tan over herself like a shower, and man was she mean. She made us run and run and run around the room until I had a stitch so bad I just wanted to double up on the floor (I am NOT a runner!). Then she had us do running relays - which really do depend on peer pressure - and it works. Then we did 3 different exercises for 2 mintues each which was exhausting!!! One involved putting your hands down on a step and jumping your feet from one side to the other 5 times, then running around the room, and repeat, and repeat and repeat, at high speed!
One girl was so tired that she ran/slipped into the raililng at the back of the room and ended up flat on her back - scary - we thought she might be really hurt! Luckily she was able to get up and walk it off.
The instructor actually 'punished' us all at one point for not continuing exercises which our relay parters were running by making us all do 100 push ups - ouch.
Anyhow, it was completely and utterly exhausting, but in a good way. I do still prefer doing choreographed exercises to music though - like body attack.
If I can only make it to the gym a few times a week though, I suppose this intense class is a good one. I'm just not sure I WANT to go again:)