Does anyone do Crossfit or Hiit workouts? What kind of workouts do you do to build muscle?

i just really started routinely exercising about three weeks ago. I started walking, now I've incorporated the elliptical trainer and weights. I was sleeved on 10/26/15. I plan to start swimming in two months, and kickboxing in three.

I just started CrossFit. I was already found Zumba and Power Yoga. It's amazing how much yoga has toned my arms and core.

I do Tabata, which is similar to HIIT. I lift weights 4 days/week, cardio (typically running on the treadmill or stairclimber) 6 days/week. Lifting weights has helped me build muscle--and I like to think it's helping with loose skin, but there's still some problem areas. If financially feasible I highly recommend a personal trainer, as working with mine has helped me become more comfortable/less intimidated by the weights section of the gym, and she keeps me from getting stuck in the same routine!

I strength train with weights 2x per week and cardio hiit 3x per week (elliptical/rowing/bike)

Ok I wanted to see if people were doing intense workout routines because I started it a few months ago and want to make sure I can continue post op. Thanks ladies!