The Doberman is, in general, an athletic breed with a lot of intelligence and drive. There are any number of things that can be done with them, though I hesitate to declare that they would excel at all dog sports, because I just don't know that.
Elka would certainly like the ones involving a ball.
Flyball is like a relay race. Taking turns, dogs go over jumps, hit the mechanism that launches the ball, catch the ball, and return over the jumps. The teams are of four dogs, there are four jumps, and it runs in "heats" (for more info, the North American Flyball Association website is http://www.flyball.org/). Flyball is fast-paced, involves running and jumping, and has the ball bonus.
Elka love environments in which she can blast along at top speed, and that, coupled with catching a ball (something she can do quite well, at high speed), I think would make for a good activity for her. I haven't taught her about jumps and jumping, something that she can of course do naturally, which makes it funny to address it as a topic. Of course Elka knows how to jump; however, I hesitate to foster jumping as an activity with our current fence situation. The fence is about four feet, a decent height and an okay deterrent. After all, Elka also respects the boundary of a baby gate. I feel that she could clear that fence if she were so inclined, though, and I'm glad she hasn't really taken the notion into her head.
A more serious dog sport is Schutzhund. "Schutz" is protection in German, "hund" is hound, and thus "schutzhund" means "protection dog". Most pictures you'll see from Schutzhund trials are of the Protection portion of it, which involves a helper in a padded suit, with a bite sleeve on one arm for the dog to latch into. There are, however, three legs to Schutzhund: Obedience, Tracking, and Protection. The official web site for the Schutzhund Club of America is here, http://www.germanshepherddog.com/, though they say they are only for the German Shepherd Dog. As I'm not involved with said sport, I'm not savvy on where the Doberman owners go, but as there are Schutzhund-titled Dobermans in existence, I know it's somewhere. The club nearest to me in fact claims to welcome all breeds, should I decide to venture into this sport with Elka.
Tracking is not something I've worked with Elka on. She is very pretty, our Elka, but sometimes cannot find a piece of hot dog that is directly next to her paw. She is rather lazy with regards to using her nose, and will visually look for something first, every time. On the long leash, though, she makes a good show of it.
Obedience is something that we work on primarily while on walks. I want her heeling next to me, not sled-dogging me down the sidewalk. It might be wishful thinking, but Elka seems to know "left", anyway, when I indicate that's where we're turning. "Right" she is less responsive about, and considering I heel her on my right, she tends to notice only when I've almost entirely turned myself.
The Protection leg is the primary reason I think Schutzhund is not the sport for Elka. While I don't doubt she would put on a good show should somebody break into the house or threaten me, and perhaps even bite, Elka does not have what is referred to in the circles as a "sharp" disposition. She can be stressed and hesitant, and really doesn't dig it if a stranger is carrying something like an umbrella in his or her hands. In the protection portion, the dog locates the helper, holds the helper there by barking, runs him down and bites (his padding) when he flees, etc. Elka loves tug of war, and could get down the sleeve portion I don't doubt, but standing up to a big scary yelling guy with one of those loud sticks they carry? I guess I'd have to have her tested in order to find out. She's my sweet girl, and I don't like scaring her for no reason.
It is important to note that Schutzhund dogs are in fact highly trained dogs, if you didn't glean that from the above information. They are trained to bite under command and in specific situations, and a good balanced working dog of the correct temperament will both thrive with this activity, and be as safe as any other dog can be expected when not primed to work. It is in fact largely a big fun game with clearly defined rules, and a good outlet for both physical and intellectual energy.
Elka's tired out just thinking about it!