Load kilometre

Why a kilometre is not a fixed measure

To your tendons, bones and muscles a kilometre is a series of landings, and every landing has a force behind it. Run faster and your stride lengthens, so you land less often per kilometre, but you push off harder and spend longer off the ground. Research into running mechanics shows that the force per step rises faster than the number of steps falls, so on balance a fast kilometre costs your tissue more than an easy one.

A climb works the same way: uphill the same kilometre costs more, so it counts as a longer flat kilometre. That is how two weeks with exactly the same distance can still be very different in weight.

What you weigh that kilometre against

The reference point is your own easy running pace, not a norm and not a target. That pace comes from your own easy runs of recent weeks, so it moves along as you change. Get faster and the reference shifts with you, and the relation between your week and your habit keeps holding.

So the measure says nothing about how well you run. It only says how heavy these kilometres were for you, compared with the kilometres you are used to.

How Trimetra personalises this

Trimetra weighs your running kilometres by pace and gradient and reads those weighted kilometres next to your time on your feet, so your running tolerance can see that a week with a lot of fast work asked more of you than the distance suggests. The reference point comes from your own easy runs; if too few of your runs carry a pace, kilometres and minutes stay in the lead and the app says so.