Take on this intense ab challenge to strengthen and tone your core before the new year! Complete 200 mountain climbers, 100 sit-ups, 100 Russian twists, and 100 side-to-sides in this full-core workout ...
Confession: Despite my lengthy career as a fitness journalist and being well-versed in the health benefits of a strong core, I have not been consistent with training my abs for a while. (Hi, holidays ...