The core muscle that does most of the heavy lifting here is iliopsoas, which is composed of two deep hip flexors.

核心肌群中负责此项工作的是髂腰肌。

youdao

Every step you take in your FitFlops improves your core muscle strength and encourages better posture and burns calories.

穿着它每走一步，你的核心肌肉力量会得到增强、身体的姿态会得到改善，而且可以消耗热量。

youdao

A new report from Harvard Medical School disclosed that traditional sit-ups only target certain muscle groups instead of strengthening the entire set of core muscles.

哈佛医学院的一项最新报道表明，传统仰卧起坐只能锻炼到特定的肌肉群，并不能起到强化全身核心肌肉的作用。

youdao

And Taproot is also launching the Pro Bono Pledge, a web-based advocacy campaign to enlist professionals to donate their talents through the Taproot Foundation and, more importantly, to flex their social entrepreneurial muscle, help build pro bono programs, and challenge their professions to adopt pro bono service as a core value.

FORBES: Professionalizing Pro Bono Volunteering