Lol, You have a couple questions I would like to address one at a time. A single Action Potential is "all or nothing" however, a single action potential is nearly useless, so your nervous system can summate action potentials with a couple of ways (these explanations are not needed to understand the whole concept). So what the muscle sees is a graded potential of activation ranging from just enough potential to create a twitch to as much as maximal force. Weight training will cause adaptations to the muscles and the nervous system. While your muscles are becoming larger/stronger your nervous system is also becoming more efficient. The increase in strength during the the initial couple weeks of training is almost exclusively a result from adaptations to the nervous system. Over time the adaptation to the muscle is to also become bigger/stronger. However, even during hyperplasia, the number of motor units will remain the same. The take home message is that even if your 5RM has doubled through all these adaptations, muscle and nervous system, the required potential for your new 5RM will be the same as the old. Intuitively, this might not be clear but if you think of the definition of your 1RM being the maximal weight you can lift, both with maximal muscle activation and muscle strength. This requires maximal effort. If your 1RM goes up, it will also require maximal effort. You're brain will treat both of those weights the same. I'm not sure if this clears up your nervous system questions but please re-ask what I didn't explain well. Your last question regarding energy system recovery is a good one. I haven't given it too much thought before now, but I in a hypertrophied muscle more nuclei are formed witch would control the transcription of more metabolic enzymes so that the metabolic capabilities of the muscle remains constant. Therefore, I would believe that the energy recovery would be similar across various sized muscles.