Sprint intervals - how to


Im pretty new at sprinting. Right now im doing a workout where I do 10 - 15 -20 sec sprints with 2 min rest in between.

Im finding it hard to get any big power out of my shorter 10 sec sprints because my cadance is so low when I start them. That is the case with the 15 and 20 sec sprints to.

So when looking at the avarage power it is lower in the 10 sec sprint and equal in the 15 and 20 sec sprint. in the 10 sec I peak out at the end and the same for the 15 and 20 with the exception that on the 20 sec power drops a bit at the end.

Ive been watching the sprint video but there is no mention of gear selection. Should I ramp up some speed beforehand so that I dont have to grind my way up to an higher cadance?

Simply, how should I think in terms of gearing, initial speed and cadance when doing short, full out sprints like this?

First off, starting at a low cadence and building and starting at a high cadence and spinning are two different types of sprint workouts. Both are helpful training but neither is really going to necessarily generate max power numbers.

To generate a max power number for shorter sprints, you want to start at a decent speed and in a gear/cadence that will let you not spin out or having to shift during the interval. You’re going all out the whole time but for me at least, mentally the effort feels like 2 separate parts - one part hammering the first half to accelerate and then one part holding power for the 2nd half.

Are you doing these on a trainer or outside?

On a trainer in erg mode on sprints that short, you kind of have to game the system to get things to work so its less than ideal. In resistance mode you still don’t get the full dynamics and body movement of a real sprint. Personally I believe the workout you are describing is better done outside.

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Thanks. I’m doing them outside until winter comes anyways :slight_smile:

So what you are saying is that I need to find an optimal speed as I start the interval so that I can put in my heaviest gear and push hard for those 20 sec without spinning out? Does that mean that I should be at a relatively high cadence from the get go then?

What I am doing now is going pretty slow and as the interval approached I shift into an heavier gear and a low cadence. Then I ramp it up during the interval.

I’m just worried that I will spin out before hitting a max power if I’m at an higher cadence from the start since I have a compact crank set.

STP has it nailed!

To improve power, you need to improve strength and leg speed. Two types of sprint.

  1. Strength sprints - start in a big gear at a low speed and go all out for 15s. Builds strength.
  2. Form sprints - start at a reasonable speed and aim for high cadence. Builds leg speed.

These are best done outside. Forget target power and HR. You just need to go all out. Leave at least 5 mins between efforts as done properly they are really hard.

If you insist of doing these inside, don’t use ERG.

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If you’re sprinting indoor DON’T SWAY YOUR BIKE!

Sprinting indoor is about fast leg spin, in big gear. I usually do 14-15T
Outdoor sprinting is a synchronize balance between pulling and pushing while keeping the core as tight as possible. Anywhere from 11-15T… Usually starts at 95 cadence till wherever, unless its force work.

If you’re not sore the next day then you’re not doing it right.

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If you are doing big sprints you’ll also need more than 2min between intervals. Aim for like 5min so that you are fully rested if you want to build max power.

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If you’re sprinting outside you’ll have a job to hold power beyond 10 seconds if full gas. That’s why timing is so crucial to the top sprinters. Anything beyond 10 seconds is a different beast, needs control to keep the effort engaged, power Iike a kilo rider.
For efforts this hard, forget watts or breathing even, just focus on a finishing line and beating an imaginary rider or bunch. Recovery comes as the reward.