If you are looking for a real challenge, then try doing the RKC Plank. Invented by a former Soviet special forces trainer, ...

Get your stopwatch out.

Planks and jumping jacks are perfectly fine workout moves. But if you combine the two together, you can actually get an even better total-body workout. Meet: the plank jack! Plank jacks involve ...

(CNN) — Planks are widely considered by fitness experts to be a fantastic exercise to strengthen the muscles in your core and elsewhere, no matter your age or physical fitness level. There are ...

Pilates pro Simone de la Rue demonstrates how to do a plank jack—aka the ultimate cardio and core-strengthening move—with proper form. A little known fact about planks: In addition to working nearly ...

Planks are a simple, equipment-free exercise that strengthen your core, improve posture, and protect your back ...

DonnaJean Wilde, 59, holds Guinness World Records for the longest plank and most push-ups by a woman. She can plank for 4.5 hours and do 1,575 push-ups in an hour. She shared tips on how to get and ...

Sign up for the best picks from our travel, fashion and lifestyle writers. How long should you be able to do a plank? According to fitness experts, it depends on your ...