Hello, I had a question regarding my fitness. I had been averaging 80 miles a week for 2 months and I was in REALLY good shape. I had a weekly long run of 17 miles and recently ran it in under 6 min pace. However, I just had to take 4 days off due to a knee problem. I just started running again and already feel like I lost a fair amount of fitness. Should taking 4 days off have this much of an effect? I would appreciate some others opinions and experiences. How long will it take me to get back to where I was? Thanks.