Set up in a standard push-up position, wrists under shoulders, low back in neutral and glutes activated.
From there you are going to begin by bringing one knee to the outside of your elbow, pausing for 2 seconds. Repeat on the other side!
Next bring the knee straight to your chest making sure the back stays in its original position. Repeat on the other side.
Finally, being the knee under and across to the opposite elbow. Again, repeat on the other side.
Set a timer for 45 seconds repeating this sequence. This is a great exercise for shoulder stability, lumbar stability, hip mobility and all around awesomeness!