Yes, adjustable air shocks can be manually filled. This is usually done with a hand pump, although some models may have a built-in air compressor. The process is relatively simple: first, locate the Schrader valve on the shock (this is typically located near the bottom of the unit). Next, attach the hand pump to the valve and pump until you reach the desired pressure. Once you've reached the correct pressure, simply remove the pump and close the valve.