Sadly, the growing sentiment is that people don't need to recover from their overly intense exercise schemes. Exercise becomes a “punishment” and if we aren’t going setting records or lying in a pool of sweat every day then we aren’t making progress.
The crazy thing is that intense group classes work…for a little while. This is even truer if the participant is new to this level of stimulus or stress. You will put on muscle and burn some fat. Then strangely, you will adapt because you body is a miraculous byproduct of the evolutionary process. So once we become adapted to the hundreds of burpees, mountain climbers and various plyo drills, what now? Over time you will become less efficient in burning calories and probably can only do so much work in a given amount of time and your body just becomes more efficient some orthopedic issues due to overuse/over stress.