Orange Theory Fitness is group training, 60 minute sessions, and every person wears a heart rate monitor during the workout. I had never heard of this company until recently. But I REALLY like their concept.
Each participant has their heart rate showing up on large monitors during the entire workout and the workout consists of a variety of intensities and exercise modalities (i.e., treadmill, rowing, weights, TRX etc)
I LOVE that they provide the heart-rate straps and track heart rate the entire workout. I really like that they provide a variety of exercise efforts (i.e., base pace, push pace and all-out pace) and modalities. I can see this being a great fit for certain people. Nothing is perfect for everyone of course.
Here’s their website
http://www.orangetheoryfitness.com/
Here is a video explaining the basics of it but you can search on Youtube for a LOT more videos to get a better feel for what the workouts are like.