I think that different Lenten metaphors speak to different kinds of people.
I can connect a little with the athletic metaphor, a little more with the battle metaphor, but most of all with the "fine-tuning your instrument" metaphor, as in this passage from Met. Anthony Bloom's Sunday of Forgiveness sermon:
"...[T]he aim of fasting is not to deprive our body of the one form of food rather than the other, the aim of fasting is to acquire mastery over our body and make it a perfect instrument of the spirit...
And so, the period of fasting offers us a time during which we can say not that I will torment my body, limit myself in things material, but a time when I will re-acquire mastery of my body, make it a perfect instrument. The comparison that comes to my mind is that of tuning a musical instrument; this is what fasting is, to acquire the power not only to command our body, but also to give our body the possibility to respond to all the promptings of the spirit.
Let us therefore go into fasting with this understanding, not measuring our fasting by what we eat and how much, but of the effect it has on us, whether our fasting makes us free or whether we become slaves of fasting itself."
Not that I've been fine-tuning my instument all that consistently, but there are still a few weeks left...