Compared to the traditional plank, this variation helps build more upper-body strength. That's because tapping your shoulders ...

“After that, you can work planks into the circuit, which will help turn on your midline even more,” he says. The only thing you need to do a plank is a swath of space where it’s safe to rest ...

Willis recommends runnning these exercises "circuit-style," doing 40 seconds on, 20 seconds off. "Three rounds if you're ...