This double-sided movement uses just your bodyweight to work your arms, chest, back, and abs.
How to do it: Lie facedown with your legs extended, arms by your sides. Extend your spine and lift your shoulders, chest, arms, and thighs off the ground, reaching your fingertips back towards your heels, palms facing out. Quickly bend your elbows and place your hands on the floor just outside of your chest, toes tucked under. Brace your abs in tight and push up into full plank position (try not to 'snake' your body, but stay solid from your head to your ankles). Lower into a pushup and simultaneously bend your left knee to your left elbow. Extend your arms and step your left foot back to plank. Repeat the pushup, this time bending your right knee in. Lower your body back to the floor with control, and repeat the extension and pushup series. Do as many reps as possible for 1 minute.
Form tip: Keep your focus on the floor to avoid straining your neck during this exercise—imagine trying to balance a broom lengthwise along your spine during the pushup and plank movements.