I have 2 goals, sprint longer, and increase average speed.
 

I have 2 goals, I want to be able to sprint a longer distance, and I’d like to push up my overall average speed. With winter hitting, and being on the trainer, what training platform should I look at, and how to I translate my goals into trainer goals/ training plans.

Thanks.

example segment I’d like to improve on.

https://www.strava.com/segments/8211779

current PR is 15:10, avg speed is 19.9 mph.

If you want to improve your power over that kind of distance (5 miles) then you need to be doing lots of threshold efforts and V02 max intervals. Suitable training platforms are Wahoo SYSTM or TrainerRoad. Those have the best online plans for this kind of thing without trying to overthink it. Just choose one of their TT focused plans and follow it. It's very easy to over-train at threshold or above, so pay attention to recovery. Decent plans take recovery seriously.

Edit: You might want to look at your position on the bike too as aero will play a significant part in your average speed for this kind of segment.

A long sprint and a 15 minute long effort are pretty much diametrically opposed to each other unless you're Wout van Aert. Meaning, you're going to have to pick one. You can improve at both and be mediocre at both, or you can be "competent" at one and really good at the other.

For long sprints or time trial follow the other poster's advice seeking training plans. But just pick one of the two.

So, what you are saying is I cant sprint for 15 minutes? 😒😁

The training requirements for a "long sprint" and a 15min long effort are quite a bit different. Choose one to really care about.

It's not a joke, some folks might have legitimate reasons to make more power for 30 seconds long than just 5 to 10 seconds for a sprint. But you can't really be excellent at that and also be an excellent time triallist. You can be competent at both, but not really excel at both.

The training to bias the amount of muscle fibers to one task or the other are different.

Unless you are asking whether to take the blue pill or the red pill your best bet is to just do this more often.

The more you try the better you'll get at it.

I mostly agree, but I think you can improve both aspects significantly if you are starting from scratch. Like in this case the OP might concentrate on longer sustained efforts for the 5 mile TT, but even a handful of sprint interval sessions thrown in alongside will make a big improvement to their sprinting power. For longer sprints (like 1 min), VO2 max intervals would also make a big difference while also contributing to the TT training. So I wouldn't say they are completely opposed goals, at least within reason. There's no reason why the OP couldn't improve both simultaneously. Something like a crit training plan might strike a good balance here.

Having said that I would concentrate mainly on TT training for the segment the OP listed. Sprinting isn't going to help there.

The "speed work" I've done trying to improve my speed was always short intervals with a long recovery, say 30" - 1' at full gas, then 5' recovery, repeat until it's obviously not working anymore, like 6 anyway, something like that. And google "cycling speed work intervals". Lots of various ways to approach this. That said, these are not sprints. Sprints are very short, like 15". Whole different deal. I've enjoyed training both things and each of them contributes to performance in the other.

If you have a smart trainer, I recommend Trainer Road.