I don’t generally like running. I believe in training by rising gently up and down from the bench. — Satchel Paige
Life is like a marathon. It's a good long race that lasts a long time (Lord willing). But you don't decide on Saturday to run a marathon on Sunday. Marathons take preparation, vision, and training. The apostle Paul says that we're supposed to do the same thing in life. We are supposed to discipline and train our bodies as the race ahead of us is long.
They do it to get a crown that will not last; but we do it to get a crown that will last forever. Therefore I do not run like someone running aimlessly; I do not fight like a boxer beating the air. No, I strike a blow to my body and make it my slave… (1 Corinthians 9:25-27)
Your body is trainable.
That's actually very exciting news because the Scriptures also say that offering our bodies is worship:
Therefore, I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God—this is your spiritual act of worship. (Romans 12:1)
Training and disciplining the body is also worthwhile:
Do not offer any part of yourself to sin as an instrument of wickedness, but rather offer yourselves to God as those who have been brought from death to life; and offer every part of yourself to him as an instrument of righteousness. (Romans 6:13)
What a great perspective to have about your body: It is a living sacrifice, an instrument of righteousness in the hands of God! THAT is a good reason to be joyful if I’ve ever seen one!
O God, I am so glad that I can prepare myself to resist the world and better myself for You! Continue to give me strength as I settle in for the long haul. I worship You as I change and offer my whole self to Your will. Amen.