During a recent hill workout with my group, we arrived at the bottom of the hill midway through the workout and were greeted by a woman walking her uber-fit looking dog, who had a ton of energy. We all know dogs are better than cats, so I used the extra 10-second recovery before the next rep to say hello to the dog (and the owner). She said, "Oh, I bet he could keep up with you going up that hill." My initial thought was, "I bet you dollars to gel packs that this dog would not only keep up, but this dog would smoke us up that hill and never be seen again." I had that thought because I noticed this dog looked like a running machine! The legs, the muscles, and even its eye of the tiger. Body type has an effect on ability and performance.
An athlete should dedicate his/her off-season (wintertime for the Mid-Atlantic area) to reshaping the body (composition). This doesn't mean we have to be vain. Although I recognize that "looking good" is motivating for some people to a degree, the research shows this is one of the least motivating reasons for exercise/training. So, to repeat, transform your body so that you perform well. Running faster and/or farther will then be easier. You'll feel like an athlete and that's a wonderful feeling. There is certainly no harm to your self-esteem and confidence if you are confident in your abilities...and happy with how you look, which you all should be.
In the breeding of animals, we do breed some types of dogs and horses to be faster and stronger. We have the capacity to be very direct and selective with animals, yet not so much with humans. Sports Illustrated continues to run its "body type" issue each year, where athletes representing the full spectrum of different sports are posing in their skimmies in black-and-white images. With a bit of photo shopping, you get to see what the body types look like across various sports. Some body types are more advantageous for basketball, some are better for discus throwing, and others are better suited to sprint up a hill like a wild dog. My observation comes on the heels of finishing a marvelously written book The Sports Gene by David Epstein, who was a pretty good collegiate runner himself. It's now in my top-5 books of all time, which is a damn tough honor to achieve.
The book highlights how our loooong genetic evolution has made certain populations of humans (based on ethnicity and/or region) primed for certain athletic pursuits. Nature vs. Nurture? It's always both, but this book delves more in detail about the who, what, when, where, why and how of elite performance from the point of view of genetics, muscle fiber types, height, leg length, ankle mass, and you name it. Epstein is an outstanding writer. He presents clarity in his points, he's very clever and witty, and extremely on-point with a scientific mind that helps dispel many myths we once held about elite performance. He even covers the game of chess in chapter 1 when he explains the vision/eyesight of elite athletes and why/how it's different than the general population. Even if you have no interest in reading about "sports," you can believe that this book often merely uses sports as a backdrop. If you're like me and you get excited reading about evolutionary biology, evolutionary psychology, anthropology and history, then add it to your wish list.
To come back to the main point, without becoming obsessed with your body, continue to brainstorm and be brutally honest with yourself about how you can change your body, or if you even want to, or need to. Consider how it can help you reach your goals. Are your nagging injuries due to weak muscles, not enough muscles/strength, or extra weight you're carrying around? The Sports Illustrated issue I mentioned above reminds us that mom and dad gave us our body types, we can only change them by so much (or so little). However, even though your upper and lower limits are set, that middle portion in between is large! Maximize it!
"Most people start running in order to get fit, whereas more people should first be getting fit in order to run." This quote reminds us to take your strength training and cross-training to heart if you have ambitious running goals. You don't have to look like "a runner" to perform your best, but you should revisit your checklist of what it is that you can do to love yourself (your body...that thing that hosts your consciousness, which makes you human).