But what did you do next?

Tore my rotator cuff doing crossfit and had surgery and never really got back into fitness.

This is obviously the real one true definition of "adult"

It is also why a lot of people in the fitness industry don't like CrossFit. The rate of injuries is absurdly high. For the longest time (maybe still) CrossFit had very minimal certification requirements for their coaches, so while some coaches had a long history and knew how to train safely, a lot didn't.

CrossFit did the community part really well, and then messed up the entire "train safely" part.

Yeah, I personally wouldn't crossfit. It's complicated doing reps for time, exacerbating form with fatigue, etc.

Also, they program stuff like high rep clean and jerks and snatches along with high intensity cardio and gymnastic movements. Never a great idea to train high power, highly technical movements with fatiguing exercises and time pressure, let alone with poor form. I did a few classes in SF coming from a background in Olympic lifting and strength sports and I really found maintaining form and safety was quite hard.

I also just found out that I have hypermobility syndrome and both running and crossfit are the worst things I could be doing because of the resultant joint instability.

Time to get into cycling!

A tale as old as time...

Running in a flat/straight line is an artificial construct. Our bodies evolved for running on rough terrain. A slower trail run will do less injury yet burn more calories than any hard sidewalk.

Race pace is tougher than training pace, too, though. I can run a comfortable few miles, but racing those same miles will cause me soreness the next few days.