maximum motor unit recruitment is the key.
http://chadwaterbury.com/the-science-of-motor-unit-recruitment-part-1/
http://chadwaterbury.com/the-science-of-motor-unit-recruitment-part-2/
http://chadwaterbury.com/the-science-of-motor-unit-recruitment-part-3/

"Lift heavy, lift fast, keep the sets shorts, and avoid failure. Those are the keys to maximum motor unit recruitment." (from part 2 of the article)

Thanks for posting the link Wlfdg - I think I've been seeing the sense in this over the past couple of weeks

Good articles, thanks.

Great reads, very interesting. I never really thought about engaging different types of nerves within the same muscle.

So, let's say, instead of lifting heavy, I just do no weight exercises in my apartment at max force.

Instead of benching, I do pushups as fast as I can for about 10 seconds for like 5 sets.

Instead of squatting, I jump as high as I can over and over for 10 seconds at 5 sets.

Would those work? Any other alternate exercises I could do in my apartment or outside without any equipment to engage other muscles?

As Wlfdg says, bodyweight exercises work but you'll eventually stall because you will adapt to your own bodyweight. You could continue with gymnastic-based training, but really the important thing to decide is what you want from your training.

If you can pick a goal to go for you can decide what training is best for you. Whether it be to improve your health, fill yourself out with muscle, gaining endurance, being able to run X miles, being a pro basketball player, etc.

I found when I wasn't sure what I wanted, I kept jumping programs and made hardly any progress! So it's worth thinking about!