Try This Move: Weighted Push Up
Classic push up w/ a Ruck Sack
In this video I'm using 30 lbs.
Start in a plank position, hands just past shoulder width, in-line with your chest. Tuck your tail bone, squeeze your glutes. Rotate your elbows back and in.
Descend to the ground, stopping a fists width off the ground. Keep your tailbone tucked, glutes tight, core engaged as you drive your hands through the floor back to the starting position.
If you've never done a push up with weight, then take extra precaution to make your form pristine before adding weight.
3 sets x 10 reps