Marks' tried-and-tested formula for the arms and abs lasts 10 minutes and involves just three exercises performed on repeat.

Training everything all at once is good for functional fitness and longevity. Here are five expert-approved exercises to keep ...

“I never do crunches, ever, and I don’t like planks,” trainer and Oner Active athlete Hayley Madigan told me.

Squeeze your abs at the top of the movement. Return to the starting position and repeat on the other side. Alternate sides throughout the set, keeping your core engaged. Recommended Sets and Reps: ...