"the skate boot has remained largely unchanged for more than 100 years."
In
this thread, I posted references to late 19th and early 20th century books on figure skating that I found at Google Books. The most recent book was from 1919, less than 100 years ago. Neither boots nor blades in these books looked altogether like modern figure skating equipment.
"Skate boots are composed primarily of multiple layers of leather that are hard and rigid when first purchased and then begin to “break in” with wear and subsequently “break down” with further use"
Largely true of Klingbeil, though even they use leather stiffened with special chemicals, perhaps glue or wax and pitch pitch. AFAIK, all the other brands, for elite level skates, use layers of artificial materials to add stiffness.
"Like dancers, gymnasts, cheerleaders, divers, and aerial skiers, figure skaters almost exclusively rotate in one direction for all spins, jumps, and lifts"
Ballet and Modern Dancers have told me this is largely untrue of them - they deliberately balance jumps in both directions, both training and performance. They are very careful about unbalanced muscle development, at the higher levels.
E.g., the retired Canadian National Ballet dancer I met (who was practicing triple axels at an ice rink) said she had used ballet triples in both directions as a ballerina, and said such symmetric training was a part of standard ballet training. (BTW, she said that in her 20 years of membership in that troupe, she had never had a serious injury or developed a long-term medical condition. She was taught that no one who used proper technique would. I don't think the same is true of figure skating.) (Note: she and the other dancers in her troupe may have been atypical of the general performance dance community. I'm also not sure how she defined "serious injury".)
I'm also very disappointed that the authors don't emphasize the injury prevention aspects of fall training.
Despite these very minor nitpicks, I'm glad that the medical community continues to be interested in the medical aspects of injury prevention in figure skating.