How do yo unlock?

The following upgrades are shown as *locked*, but it neglects to explane how one should unlock them (hint hint).

Training Yard

Spa

Trainer

Does anyone know?

One of my gladiators saw a key on the ground a few fights ago but someone kicked sand in his eyes...and that was that, no happy endings at the spa for him.

Interesting... very cool. Thank you for the info/response! :-)