This is an excellent exercise to engage your core and many major muscles groups including your abs, lower back and quads.
Lie face down with your elbows to your sides, your head facing forward and palms flat on the floor.
Keeping your knees on the floor positioned behind your hips, engage your core and glutes, raise your body from the floor, supporting your weight on your forearms and knees while breathing freely. Concentrate on maintaining a straight line through your core and legs.
Hold the plank position maintaining good form and keeping your glutes tensed, then return to the start position slowly and with good control.
Aim to hold for between 30 and 60 seconds.