It's not an easy answer. Everything you need for classical ballet is in classical ballet; well almost. If you want to get really specific, ballet does not train your anterior calf muscles sufficiently, so you do need to do other stuff to completely train the lower leg. However, proper and thorough training, in class, will make you a good dancer. When I was with Joffrey, I danced, ran, biked, swam, worked out with weights- wow, where did all that energy go?- and felt it enhanced my dancing, but I came from a sport background, so it was natural for me to continue all those things.
In sports (yes, ballet is a sport, but let's just use "sports" to mean other than dance for right now), you have your sport-specific training, and then you have weight work in the gym, plyometrics, cardio, etc. Gone are the days when you just did your sport, and nothing else. It has been proven, time and again, that a complete athlete needs to do many things, as there is no one perfect exercise. When someone wants to get into better physical condition, they should do a variety of physical activity, not only for the body, but for the mind as well.
That being said (one says that when one is about to apparently contradict one's self), if you want to be great at any one thing, you have to concentrate on that one thing. The great cyclist, Eddy Merckx, 5 time winner of the Tour de France, was once asked, "Eddy; how do I become a great bike rider?" His answer: "Ride... a lot." This is true of anything. If you want to be a great painter, you paint. A great violinist, you play the violin, a great dancer, dance. It's not simply for the technical requirements that must be mastered, the craft part of any endeavor; it's what takes the good technician and makes him/her an artist. It's what makes a Michael Jordan, a Baryshnikov, a Picasso, a Beverly Sills, a Meryl Streep.
I firmly believe young people should do everything, go everywhere, experience life to its fullest extent (without doing stupid crap like drugs or texting while riding a bike). If you want to be great at something, you have to prioritize. Great artists are constantly learning, and the only way you can learn about your art is to do it, a lot. It's the tiny, seemingly insignificant details that only surface when you explore and delved into the deepest parts of whatever you're doing. It's what happens when you've done a variation a thousand times and you find something new, when you throw that slider just a little differently because you've thrown in a million times and something tells you to do it this way, now.
I was lucky enough to study with the great Stanley Williams. His classes sometimes bordered on the simplistic; we would do the same simple exercises over and over and over. Often our grande allegros were ludicrously plain, even boring. He kept telling us that if we just kept doing these exercises, properly, our bodies would be able to do whatever we told them to, because we were training them in the right way for ballet. One day, after class, I was so frustrated by not doing all the different big jumps I wanted to do, I just went for a double saut de basque... and did it. I stopped and looked around. All the other guys were looking at me. I pointed to a friend, David Keary, and said, "You try it." He did and it worked. We hadn't practiced saut de basque in weeks and yet, we could do them better... That's when we realized that Stanley was a genius.
Ballet is in the training. Sure, do other things to keep yourself mentally sharp and to avoid burnout, but if you want to dance, dance. A friend of mine mused on why some dancers today were retiring earlier than dancers of bygone days. In my Father's day, dancers just danced, and many had very long careers and were healthy all their lives. Yes, technique has improved, and multi-sport athletes are amazing physical specimens, but maybe dancers should just dance, more.
So, Jerry, how do become a great dancer?
Dance... a lot.
Thanks, Eddy.
See you in class.
