Triangle / Close / Diamond knee push-ups

Instructions

Get into a face-down position on the ground, with a straight back, and supporting your weight on your knees and your hands placed under your chest. Your indexes and thumbs touch each other so that your hands form a triangle.
Bend your elbows to slowly lower your body until your chest is close to the ground.
Hold this position for one second, then go back to the starting position.

Muscles