This loaded, full length variety is the highest threshold of anti-extension load in the aleknas continuum of exercises. The added load to are arms creates a large lever and therefore high force which your abdominal region needs to control, along with the added load of the lengthening legs. Definitely one to build up to because if you cannot control the key component of keeping your back into the ground throughout (without holding your breathe) then you will get force creeping into your back.
Do not hold your breathe
Keep tension in the arm pits
Drive the upper body movement with your elbows
Kiss the floor with your heels
Targeted muscles trained
Key movements trained
Shoulder elevation through flexion
If you have recent shoulder issues then this overhead loading pattern needs to built in to, maybe consider Aleknas Arms, or Aleknas unloaded first. The reason being that you are taking your arms into a fairly vulnerable position with load and therefore your ability to keep the shoulder stiff in the outer ranges is very important.
If you wanted to make this more difficult without adding more load you can execute the same movement but laying on a bench. This removes the floor as a limiting factor and therefore will aid your control through a greater range of motion.