She could feel it.
Deep within her core, she could feel herself getting stronger.
With each passing day, she learned something new or improved her foundations. Ember went into this training knowing that it would be incredibly grueling and demanding. But even after knowing about the training, had doubts about how much she could improve in such a short time.
She honestly didn't even mind the food at this point, she was so engrossed in her intense training that the food was more like fuel than enjoyment. Although, she did miss dessert a lot.
At the end of the third day, or at least when Captain Alexis told her to stop to rest for the next day, Ember hadn't been able to strike any tree without destroying it. However; there were a couple of times toward the end when she was able to pierce through the trunk and have it stay standing until it began to collapse under its own weight.