...
It's a bit different with singles skaters, especially as the age of skaters starting skating and jumping gets younger. It's possible that coaches OR skaters tried to "keep" their physiques as close to how the skaters were when they're landing their jumps easily, and avoid strength training so that they don't build any muscles that can interfere with the jumps. And then when they finally did it, they're already carrying injuries which might also get impacted by the muscle training.
Very good mention.
What I find absolutely fascinating and shocking is the lack of stenght training and the apparent lack of knowledge coaches have about developing muscles and flexibility slowly described in a lot of these citations.
I am not really persuaded that lack of knowledge is the biggest problem. I am rethinking the possibility of having the knowledge, but undervaluing its importance.
-------
More times I read that skaters or coach mentioned that higher weight means higher load on joints and bigger possibility of an injury.
"Higher" weight was mentioned, NOT weight ABOVE skaters "ideal weight" (based on body type, muscle mass, water contain etc.). Which unfortunately may lead to idea of kilograms in prepubertal age like @rabidline mentioned.
Landings in triple jumps are around 5 to 10G - force (from Alexei Mishin's book). Coaches may think that for example: skater with 40 kilograms - it means 400 kilograms per maximum during landing. 50 kilograms - 500 kilograms per maximum during landing. The results: weight of 40 kilograms is "more safe" and injury protective.
I believe this is the biggest argument used by coaches to support low weight.
This teory is not right in my opinion.
Unfortunately there is probably lack of science studies proving that bigger muscle mass and right centering of joints are more protective than lower weight. Not to mention that in figure skating it is not easy to prove this as we do have a lot of smaller and bigger traumatic injuries caused by falls.
Even some studies are supporting the lower weight idea into some degree:
Google Scholar
BUT...
What is problematic with this study? It uses the weight of an athletes and adds additional weight. The mean height was 176.2 cm, the mean weight was 71.58 kg, the mean percentage of body fat was 22.60% in the study, athletes got from 1 to 5 pounds of additional weight. While our skaters are very often forced to reduce their weight below norm and body fat to lower norm or below norm which leads to multiple health troubles. But it also leads to situation of muscle weakness with less power and dynamics which is essential for skating jumps. Being forced to reduce muscle mass leads to worse protection of joints. Malnutrition also leads to worse concentration which is important for both jumping and performance.
(More people points from videos that some girls are visibly depressed and crying in Eteri Tutberidze's group. But is it really the strictness on the practise causing this? Or mental difficulties during puberty? Or side effect of malnutrition?)
As to skating jumps there are another parameters as well.
Speed of rotation is determined by skater's technique of upper arms' movement, but it is also influenced with "body curves" and width of shoulders and hips. It naturally creates much more difficulties for mature body to rotate fast comparing to prepubertal body, it is not just weight issue. Right jumping technique is influencing height and the overall quality of the jump a lot.
Not having science studies we can try indirect ways of proving that too low weight is not injury protective.
Looking at list of public stress fractures we may very well exclude the possibility that only athletes with higher weight (based on more muscular body) sustain stress fracture. More ladies on the list were in prepubertal age with extremely tiny bodies...and it didn't protect them.
We know that malnutrition leads to more injuries and lower bone density. There are studies proving this.