Figure skating is a sport that puts significant strength and flexibility demands on the body. Athletes in other sports may say that figure skating is not a 'sport', and it is more artistic performance, but they are quite wrong! Skaters are some of the strongest athletes in the world. I can recall a Sports Physical Therapy class I attended in college in which a strength and conditioning coach took us through some difficult training exercises. Out of 45 or so people, I was the only one who could do a one-legged squat! His response was, "Oh, of course, you're the figure skater."
Some skaters have natural strength, balance, and core strength that will take them through the lower levels of skating quickly, but the majority of skaters need to improve upon each of those attributes in order to progress to higher levels. Once the 'naturally talented' skaters reach a level at which double jumps and difficult spins are required, that natural ability will only take them so far. The core strength and plyometric strength requirements of the sport are significant, and at some point, a skater needs to build strength beyond what he or she naturally has. By completing an off-ice training program at least twice a week, skaters will progress their on-ice skills at a faster pace, and be able to handle the strength demands of jumping, spinning, and longer programs.
Checking out of a jump involves the contraction of the muscles in the abdominals and the lower back, to resist the rotational force of the jump. Without core stability, a skater will have difficulty maintaining the body over the skate and continue turning past the landing point. Also, to achieve the correct height to perform a jump, a skater requires significant plyometric strength throughout the lower extremity, especially the quads and gluteal muscles. This can only be gained with functional and plyometric strengthening off of the ice.