This phrase is British English and used more commonly in the UK than other English-speaking countries. After her speech, her British colleague said, 'More power to your elbow!'
Pro Tip 2/3
Supportive Tone
Use it to show approval and support for someone's actions or decisions. You're volunteering this weekend? More power to your elbow!
Pro Tip 3/3
Motivational Context
It's often used to encourage someone who is working hard or facing a challenge. You're almost done with your project; more power to your elbow!