I actually started riding fixed because of my knees. I was in a moped accident and ruined the rear muscles that keep the knee stable (ligament?). My docter said to fix the knee I had to ride a spinning bicycle. It has a flywheel that keeps it in motion so you can't stop pedaling. During that time, I saw this thing on the news about these bicycles called "fixies". I instantly knew the solution. It actually took a while to save money for my first wheelset. After that, I kept improving. In the beginning I was using clips to keep my feet from moving but found them very uncomfortable. They were old and made from metal and didn't provide a good platform for pushing the bike to the limits. I went over to straps but I was cured from that quite quickly. I wasn't able to get them on my shoes properly and had some space when pulling up. That is when my knees started to hurt again. I then made one of the best decisions so far: SPD shoes. I haven't had any knee problems so far. Just a torn muscle in my uper leg but that's not because of my SPD's.
I actually started riding fixed because of my knees. I was in a moped accident and ruined the rear muscles that keep the knee stable (ligament?). My docter said to fix the knee I had to ride a spinning bicycle. It has a flywheel that keeps it in motion so you can't stop pedaling. During that time, I saw this thing on the news about these bicycles called "fixies". I instantly knew the solution. It actually took a while to save money for my first wheelset. After that, I kept improving. In the beginning I was using clips to keep my feet from moving but found them very uncomfortable. They were old and made from metal and didn't provide a good platform for pushing the bike to the limits. I went over to straps but I was cured from that quite quickly. I wasn't able to get them on my shoes properly and had some space when pulling up. That is when my knees started to hurt again. I then made one of the best decisions so far: SPD shoes. I haven't had any knee problems so far. Just a torn muscle in my uper leg but that's not because of my SPD's.