That's true, we don't want Yuna to get hurt ! But Mao seems ok despite all her triple axeling.
Because they have different style of jumps. Mao puts a sudden stop on her speed and translate that energy into the air, and faster rotation in the air w/ less speed & travel distance.
Basically that is much safer than either Yuna's style - i.e. throwing herself into the air at full speed.
Mao's style is probably less stress on her joint landing but loses momentum so that the next jump will be much harder.
Yuna's style helps her to use more of her leg muscle on the 2nd jump as she mainly used her speed on the 1st jump. But the landing from her 1st jump is likely to put more stress on her joint.