Place your hands on the floor slightly wider than shoulder-width, arms straight, and extend your legs back so your body forms one rigid line from head to heels. Lower yourself until your chest is just above the floor - elbows tracking back at roughly 45 degrees from your body, not flared straight out - then press back up to full extension. The line is everything: core braced, hips neither sagging nor piked, the whole body moving as a single plank from the first rep to the last.

Works: chest, shoulders, triceps, core

Breathing: Inhale on the way down, exhale as you press up.

Common Mistakes: Sagging through the hips or piking them up, cutting the range short of chest-to-floor depth, and flaring the elbows straight out to the sides.

Make Easier: Drop to your knees keeping the straight line from head to knees, or elevate your hands on a sturdy surface - the higher the hands, the lighter the load.

Make Harder: Slow the lowering to a three-count with a pause at the bottom, or shift the load with Push-Ups - Close Grip or Push-Ups - Wide Grip.