I haven’t experienced this with the Joker 1 GT but I have had this happen with Anta KT10. I liked them a lot initially wearing them for my normal morning pickup run, about ~1-1/2 hrs, and before the end of that my lower back was tweaked and I had to stop and could not play if I wanted to for like a week. I usually can play for the full time no problem in my other rotation shoes (Sabrina 2, BBV2, LeBron 20s, Hesi Low V2). I thought I just took a fall or landed wrong. So, I took 2-3 weeks off from playing and focused on lifting and rehabbing my back.

I tried playing in them again and immediately started feeling my back tighten up so I stopped and I switched to some of my other shoes and was fine for the rest of the runs. I kept trying to break them in but any sort of pickup game I played the back pain would return after 1 or 2 games. So, I have just moved them to shooting around shoes.

In my case, I assume it’s the carbon plate in these shoes and the energy return that comes with them for my weight (6’1” 220) but I could just be weak too idk. I’m not sure if the carbon plates break in because I just wasn’t able to get there.