Different bikes, different muscles?

I had the same, when I got on my road bike earlier this year for the first time in about 2 years, had only ridden fixed inbetween. It'll be OK, it just feels weird for a couple of hours. Now I do a road ride every weekend and all is fine. I've done a road century since with no problems.

Good this is what i was hoping as i only did like 20 miles it wasn't really enough to work out aches and pains and that. Well problem solved then i will just assume if i can ride fixed around london then i can probs ride 100 miles in under 4 hours now in the country side for sure.