1)
What is the significance of girding her loins with strength?
1.
Malbim (Derech ha'Muskal): This refers to investigation, which is compared to going - one goes from idea to idea. She girds her loins to go from achievement to achievement, from understanding to understanding.
2)
Why does it say "va'Te'ametz Zero'oseha"?
1.
Malbim (Derech ha'Muskal): Regarding deeds, she invigorates her arms to do Mitzvos and good deeds without laziness.