I had a comment posted asking me what a spinerval is.
Here is the link and then I'll give you my interpretation of a Spinerval Video/DVD.
Spinerval Videos/DVDs are training tools for you bike. They also produce running and swimming training tools as well.
You can purchase a trainer,
on this site or on EBay or at your local bike shop. There are good ones and then better ones. I like mine which is the Kinetic SuperFluid Tainer. However ask those you know and trust that use trainers and they may have better suggestions.
The DVDs range in difficulty and length. I currently use the Team Clydesdales and Sweating Buckets Spinervals.
I get great workouts using the DVDs and I see progress in my road work as well. I am increasing speed and my endurance is getting better as well.
I hope this helps.