I heard this line this morning in the gym and a huge grin spread across my face. An older gentleman was saying this (in jest) to his trainer as he was doing step-ups. It made me smile because I remember the days of enjoying putting my clients through painful workouts, and smiling when they'd return a few days later saying how sore they were (yes, people thought I was somewhat demented that way). Deep down, however, I know that the pain was for their good - it would make them stronger! I loved it when my clients wanted to work harder because they knew that that was how results would come.
I have personally gone through this a lot. With each meniscus tear, torn fascia, slipped disc... God has taught me something new. As a Christian, I have grown spiritually from every physical injury I have had. I actually caught myself saying something like this to God the other day: "Bring it on, if that's what You need to do to get me where you want me to be. Or, Thank you, God, may I have another?" I realize this is a dangerous prayer, but it's worth it!
"Consider it pure joy, my brothers, whenever you face trials of many kinds because you know that the testing of your faith develops perseverance. Perseverance must finish its work so that you may be mature and complete, not lacking anything." James 1:2-4