The stuff on fast twitch vs slow twitch is super interesting in my opinion. It seems a lot has come out on it in recent years. I think you could make an argument speed is potentially the most important physical attribute for striking sports. If you are interested Andy Galpin is probably the lead sports scientist who also work's with MMA fighter's (he's worked with Brian Ortega, Patrick Cummins and a few other UFC fighters). This was a decent conversation where he get's into method's to optimise fast twitch ratio; He's also been on Rogan's podcast and a few other's but this was the most performance oriented conversation I've seen him.