Remove
Friction. 
Proactively remove it.

Practice feeling where the Resistance lies
so you can play with it
touch it
move it.

I've come to believe that as motivational as that may sound, most individuals haven't earned the right to be "worked out."

"Can you make it hard today?"

What's the optimal environment that would support that request?

Plenty of sleep--consistently.  Insulin is stable, hormones aren't flippin' around like fish on the pier.  Eating high quality, clean, nutrient dense food.  Life is not too stressful.  AND...
you have lots of experience training in that cellular environment.

So...'can you make it hard today?'

No.  Not for you.  Not today.  You have bags under your eyes.  You're anxious, you're checking your phone in a class you paid for.  If I stress you today, your body will perform this equation:

Preexisting Stress + Exercise Stress = Shut down

Your body cannot differentiate between stresses.  It cannot understand that your relational stress is different from your work stress, and that is a different stress from whatever it is you're calling your Elite-Endurance-Shred-Cardio-Sculpt-Sizzle class.

So...'can you make it hard today?'

Sure.  Go home, get 7+ hours of sleep tonight.  When I see you next week, tell me all the reasons you were unable to do that one simple thing.

"People who lack language have to do a ton of prospecting.  People who have strong language--every time they open their mouths--they speak to their purpose."  -Joe Stumpf

Read that which improves the mindset, not just distracts it.

This is the beauty of sacred texts and inspired writing.

Try Rumi, try John O'Donohue.

Fill your lexicon with expressions for Beauty, Wisdom, Truth, and Goodness.