Tell me about sprinting. 
I have my laptop set up on top of my treadmill and can plod along slowly or at a good clip, elevation or flat. 
Just now I decided to just sprint as fast as I could (turned out to be 6,8mph) for as long as I could (little more than 30 secs) before I got uncomfortable and wanted to stop.
HOw long between sprints and how many sprints on average do you do?

Thanks

Most important thing is to get as complete a recovery as possible between intervals.
Think "fresh legs" for each sprint.
If 30 sec. is your upper limit you want to stop at 25 sec.

Thanks! This will be a great starting place for me.

For the record, Tabata's can't be done effectively sprinting. It takes almost the whole 20 sec. to accelerate and all of the 10 sec. to decelerate.
 
Sprinting on a treadmill is not very effective since you aren't actually propelling yourself forward.

As a rule, if you can perform a movement on a natural surface it's machine based counterpart is virtually pointless.

I would recommend starting with hill sprints... they are harder but they teach you the proper sprinting form.

and they're far less likely to cause injury

 I started Tabata sprints this winter and found that the 20/10 split worked fine for me(I'm not a runner) and was well suited to my ball hockey(played in a gym so lots of stop/start intervals type exercise). Since beginning the sprint regimen I noticed an almost immediate improvement in my endurance and speed.

 In terms of running Tabata sprints were actually easier on my body. Prior to 2011 I would go on these longer(plodding) runs of 4KM+ and usually by the 5km point my ankles, knees, back and shoulders would start aching. As long as I watch my form the 20 second sprints were tough but the 10 seconds of (walking) recovery sufficient. No longer is distance my goal when I run.....I will do a warmup run, a set of sprints, a set of box jumps and a set of walking lunges. Easier on my body and what a burn! Far more effective for me than a monotonous plodding run.

http://rolfdevinci.blogspot.com/2010/12/tabata-sprints.html

 That said I also do hill intervals. I found a moderate grade street in my neighborhood that is perfect. Not to long or steep with little traffic.....I hate running on sidewalks with all the dips by streets and driveways. Good way to cause injury with a misplaced foot while sprinting.

 

I love sprinting.  I think it is one of my favorite ways to move my body for exercise. 

I'm not really a fan, but then I wasn't really built for speed, haha!

Not to step on toes. No one, not even Usain Bolt can effectively accelerate in 20 sec. to gain the training adaptation necessary to consider it a Tabata Protocol. You would have to be at full speed on your second step and be able to stop at exactly 20sec. If you can't do that it's just an interval.
That is the reason it's a stationary bike or front squat protocol.

Good to know, thanks