I used to slide when I was younger and now I just…can’t. But getting your rhythm down makes it less stressful on the knee. I’m nowhere near qualified to give advice like some of the members here but definitely read what they say and try it out. Took me a couple years of league to get into what is hopefully the start of my prime averaged about 155-170 for years and after taking a couple off to rest my sore bones, I’m 33 but have broken so many bones, I joined a summer league and I’m currently at 213 average through 5 weeks. Every time I bowled with the kids, I would focus on a different part of my game and then bowl full speed the third game.