Before Christmas I hadnt really ridden my bike for 2 years.
The urge is to go out and try and ride like you used to. Doesnt work just kills you.
I actually found a turbo trainer (in the winter months) very useful as I could set myself targets, and I because its unlike real riding I couldnt see how bad I was. When I was very unfit I found riding off road very frustrating as I could easily see how unfit I was and found every thing very very hard. I also found that technical skills were almost none existant because everything was so hard.
4 months after getting back on the bike I’ve probably now got 80% of my fitness back, and I actually enjoy riding trails again, rather than every pedal turn being a huge effort. The first month was just pain and I didnt think I was achieving anything. However after that my fitness just appeared to click.
Start slow and short distance, continue doing short and slow distances until it stops really hurting and taking you a long time to recover, then gradually increase the distance and speed.