Why did you get into roller derby? A lot of people do it for the fitness aspect, but then are completely sucked into world of roller derby. I was turning forty the year I started, and I decided that either I was going to jump out of a plane or tryout for roller derby. Guess where I ended up?
Before I tried out for derby, I was very into fitness; I worked out at least five days a week and loved being active. I always liked moving around, but I hadn't been involved in organized sports for over a decade. When I first started skating again (after a twenty year hiatus) I was in pretty good shape; my endurance was high and due to my bike riding, my legs were strong. I also did weights and ran.
Last year, someone asked me if I considered myself an athlete; the question really made me sit and ruminate for a while. Was I in shape? Yes. Did I play a sport? Yes....but was I an athlete? Maybe. It was funny, but I didn't think I was hardcore enough to call myself an athlete at the time, even though I was making five practices a week and training outside of derby on a regular basis. It was purely my perspective that kept me from calling myself an athlete; I felt like I hadn't earned it yet. Looking back, I now understand, it was pretty ridiculous.
I am definitely an athlete; if I didn't have derby, I would still pursue active training in other disciplines, such as running, or biking, or even martial arts. If wheels disappeared from the earth tomorrow, I would still be out there pushing myself. My league is now in derby break and I'm making myself take up yoga, because I need to be more flexible to be a better skater; I'm also focusing on yoga because it is a challenge, and I suck at it right now. Every day starts with yoga, and I gnash my teeth every time my balance is tested, but I keep pushing through because I am an athlete.
Try your local Crossfit...I think they are a fabulous organization.