That tiredness might be all in your head.

Here’s how to work past a mental block if your muscles still have some energy.

That’s right: Mental fatigue can seriously affect your workout.

person at the gym using battle ropes to work out

Shutterstock.

The first step is to understand your fatigue triggers.

It was previously assumed that peripheral fatigue dictates a certain threshold at which your muscles give up.

Want to test it out?

But hit mile seven, and every subsequent mile feels like a drag and you start to slow.

“Performance is not directly limited by muscle fatigue but rather by perception of effort,” he says.

The riders who had tired their brains before the workout demonstrated significantly shorter times to exhaustion.

Any trick that reduces that perception of effort would improve your endurance performance.

First, keep the upbeat thoughts coming as yousweat it out.

Next, make your brain associate exercise with something that feels good.

(Music helps, too!

Here are some of thebest running playlists to power you to a new P.R.)

But for those who prefer to swallow your beverages, caffeine can also work wonders on brain drain.

Your movement becomes more automatic and seems less daunting, and your workout and body suddenly feel limitless.

(More here:How Drinking Coffee Before a Workout Could Improve Your Performance)