At F45, you can expect to squat and lunge at any given moment, train with kettle bells and battle ropes, and essentially never stop sweating (via DMarge). However, if you're not used to these movements, it's easy to find yourself at regular physiotherapist appointments.

Do physiotherapists endorse this workout? Holly Brashe, a physiotherapist at Square One Physiotherapy, certainly seems to believe they're not as bad as people think they are. "If we take a look at what F45 consists of — a mix of cardio days, bodyweight exercise and days where moderate weights are used — I'd say it's a real positive for many physios in that it gets people exercising and moving," she said to Australian publication Coach.

"Where problems can occur is during high-intensity exercises when people start to fatigue and revert to the 'easiest' way to do a movement, which might not be the correct biomechanics," she continued. Essentially, if you have terrible form, you're bound to get injured. Brashe recommends being honest about your own body's capabilities and also visiting physiotherapists when you feel even the slightest bit "off."

F45 also has trainers who can modify exercises for you (via GymPass) so that you aren't giving it 100% when your body can only do 70. Additionally, make sure to schedule in an extra-long stretching and recovery period post-workout so that your body can make it to the next session.