Since I began this journey in August of 2009, I've had a few injuries and a seasonal workload that has taken me away from my fitness program. Nothing too serious and usually less than 2 weeks to heal. But still there's that uneasiness on that first day getting back on the wagon. One thing different about me now is that I don't go back into it with the idea of making up for lost time. The time is gone, you can't get it back. Pushing yourself hard on the return is the surest way to yet again injure yourself. Instead, I think back to that first day of August way back when and think "That's really all I have to do today." Of course after I actually do that first workout I feel good about myself and soon enough, I'm back to where I was.
Sooner or later something is going to disrupt your journey. It's all how you deal with it the defines how successful you are.